80 results on '"NAOYA OSAWA"'
Search Results
2. Direct and indirect effect of cannibalism and intraguild predation in the two sibling Harmonia ladybird beetles
- Author
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Arash Rasekh and Naoya Osawa
- Subjects
coexistence ,common species ,generalist ,rare species ,reproductive interference ,specialist ,Ecology ,QH540-549.5 - Abstract
Abstract In this study, we focused on the direct (i.e., predation) and indirect (i.e., potential threat from coexisting with a larger individual) effects of cannibalism and intraguild predation (IGP) during larval stages of two sibling ladybird beetles. These effects play an important role in the coexistence of the generalist–common Harmonia axyridis and specialist–rare H. yedoensis (Coleoptera: Coccinellidae). Direct predation effect of cannibalism and IGP was asymmetric in the two sibling ladybird beetles; the fourth instar larvae of H. axyridis were better intraguild predators than cannibals, while the reverse was true in the larvae of H. yedoensis. Neither cannibalism nor IGP significantly affected female body weight in either species. Larval H. axyridis surviving exposure to cannibalism or IGP had a reduced number of ovarioles as adults, whereas adult H. yedoensis ovarioles were not affected. For the indirect effects, longer developmental times in males and females and a lower total number of ovarioles in females were detected in H. axyridis. In H. yedoensis, shorter developmental time of males, lighter adult weight and fewer total ovarioles in females were observed. Olfactometer choice experiments clarified that the fourth instar larvae of H. axyridis avoided the first instar conspecific larvae, while those of H. yedoensis were attracted to the odors from H. axyridis and conspecifics. Thus, H. axyridis has an avoidance mechanism only for cannibalism but not for IGP, whereas H. yedoensis does not have any avoidance mechanism. These different behaviors in the direct and indirect effects of cannibalism and IGP observed in the laboratory may play important roles in the coexistence of generalist–common H. axyridis and specialist–rare H. yedoensis in natural conditions, compensating for the large handicap of H. yedoensis at reproductive interference from H. axyridis.
- Published
- 2020
- Full Text
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3. Synthesis of fluorescent Molecularly Imprinted Polymer Nanoparticles Sensing Small Neurotransmitters with High Selectivity Using Immobilized Templates with Regulated Surface Density
- Author
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Yasuo Yoshimi, Yuto Katsumata, Naoya Osawa, Neo Ogishita, and Ryota Kadoya
- Subjects
molecularly imprinted polymer (MIP) ,fluorescence ,solid phase synthesis ,acetylcholine ,serotonin ,dopamine ,Chemistry ,QD1-999 - Abstract
To develop nanosensors to probe neurotransmitters, we synthesized fluorescent-functionalized molecularly imprinted polymeric nanoparticles (fMIP-NPs) using monoamine neurotransmitters (serotonin and dopamine) immobilized on glass beads as templates. The size and fluorescence intensity of the fMIP-NPs synthesized with blended silane couplers increased with the presence of the target but were insensitive to the target analogs (L-tryptophan and L-dopa, respectively). However, when the template is anchored by a pure silane agent, both the fluorescence intensity and particle size of the fMIP-NPs were sensitive to the structural analog of the template. Another fMIP-NP was synthesized in the presence of poly([2-(methacryloyloxy)ethyl] trimethylammonium chloride (METMAC)-co-methacrylamide) grafted onto glass beads as a dummy template for acetylcholine. Acetylcholine increased the diameter and fluorescence intensity of the fMIP-NP, but choline had no effect. When the homopolymer of METMAC was used as a template, the fluorescence intensity and size of the resulting nanoparticles were not responsive to either acetylcholine or choline. The principle of increased fluorescence intensity due to specific interaction with the target substance is probably due to the increased distance between the fluorescent functional groups and decreased self-quenching due to the swelling caused by the specific interaction with the template. The results also indicate that MIP nanoparticles prepared by solid-phase synthesis can be used for targeting small molecules, such as the neurotransmitters addressed in this study, by adjusting the surface density of the template.
- Published
- 2023
- Full Text
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4. High Variability in Pre-Oviposition Time Independent of Diet Available at Eclosion: A key Reproductive Trait in the Ladybird Beetle Harmonia axyridis (Coleoptera: Coccinellidae) in Its Native Range
- Author
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Séverin Hatt and Naoya Osawa
- Subjects
predator ,fecundity ,fitness ,starvation ,alternative food ,Perilla frutescens ,Science - Abstract
While insect predators need high-quality food to reach sexual maturity and reproduce, starvation following adult eclosion may occur when prey are missing in agroecosystems. This study explores whether the type of diet available at eclosion determines the future fecundity of newly emerged adult predators. In a laboratory experiment, three different diets (i.e., flowers of Perilla frutescens (L.) Britton, eggs of Ephestia kuehniella Zeller as prey, or no food) were offered to adult females of the ladybird beetle Harmonia axyridis Pallas during their first three days after adult eclosion. On the fourth day, each female was paired with a prey-fed male and the pair was subsequently fed with prey. Diet at eclosion did not affect pre-oviposition time, the number of eggs oviposited daily, or the viability of egg batches. High variability in pre-oviposition time among females was observed for all diets. Significant negative linear relationships were found between pre-oviposition time and both the number of eggs oviposited daily and the viability of egg batches. This study clarifies that the food readily available at adult eclosion does not affect the capacity of H. axyridis to reproduce, provided that adults find prey within a few days. More generally, it shows that the reproductive traits of H. axyridis allow this generalist predator to be highly adapted to heterogenous environments in its native range. It is concluded that the variety of habitats offered by diversified agroecosystems may highly benefit the ladybird beetle H. axyridis, and potentially enhance its ability to biologically regulate crop pests.
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- 2021
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5. Prevalence of male-killer in a sympatric population of two sibling ladybird species, Harmonia yedoensis and Harmonia axyridis (Coleoptera: Coccinellidae)
- Author
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Suzuki NORIYUKI, Yuichi KAMEDA, and Naoya OSAWA
- Subjects
coleoptera ,coccinellidae ,harmonia axyridis ,h. yedoensis ,aphidophagous ladybird ,early male-killing ,maternal investment ,maternally inherited bacteria ,sex ratio ,sibling cannibalism ,sibling species ,Zoology ,QL1-991 - Abstract
In predatory ladybirds male embryos in clutches of eggs infected with male-killing bacterial endosymbionts do not hatch and are consumed by female hatchlings. Moreover, it is predicted that infection with male-killing bacteria should be prevalent in a ladybird population if the fitness advantage to female ladybirds due to the resulting reallocation of resources is high. We compared male-killer bacterial prevalence in two sibling species of the ladybird genus Harmonia that use different host ranges. Harmonia yedoensis feeds mostly on the highly elusive pine aphid and its hatchlings can greatly enhance their ability to capture prey and thus their survival by consuming un-hatched eggs in the clutch. In contrast, Harmonia axyridis feeds on a wide range of prey and consumption of un-hatched eggs by the hatchlings does not necessarily increase their foraging success. In the study area where these two species of ladybird occur sympatrically 14 of the 22 females of H. yedoensis (64%) laid clutches of eggs of which approximately only a half hatched and did not produce male offspring, whereas only one of 12 of the females of H. axyridis (8%) exhibited symptoms indicating infection with male-killing bacteria. In the H. yedoensis that exhibited symptoms of being infected with male-killing bacteria, the total allocation of resources to each hatchling, which was provided by laying larger eggs and eating the un-hatched eggs in the clutch, was considerable. These results suggest that the difference in the prevalence of infection with male-killing bacteria in these two species of ladybird may reflect differences in the quality of their prey and their foraging behaviour.
- Published
- 2014
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6. Reproductive Interference and Niche Partitioning in Aphidophagous Insects
- Author
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Suzuki Noriyuki and Naoya Osawa
- Subjects
Zoology ,QL1-991 - Abstract
The range and quality of prey species differ greatly among closely related species of predators. However, the factors responsible for this diversified niche utilization are unclear. This is because the predation and resource competition do not always prevent species coexistence. In this paper, we present evidence in support of reproductive interference as a driver of niche partitioning, focusing on aphidophagous insect. Firstly, we present closely related generalist and specialist species pairs in aphidophagous lacewings to compare the reproductive interference hypothesis with two other hypotheses that have been proposed to explain niche partitioning in lacewings and sympatric speciation through host race formation and sexual selection. Secondly, we present a case study that shows how reproductive interference can drive niche partitioning in sibling ladybird species. Thirdly, we show that many ladybird genera include species inhabiting the same region but having different food and habitat preferences, raising the possibility that reproductive interference might occur in these groups. Finally, we show that intraguild predation cannot always explain the niche partitioning in aphidophagous insects including hoverflies and parasitoids. On the basis of the evidence presented, we urge that future studies investigating predator communities should take account of the role of reproductive interference.
- Published
- 2016
- Full Text
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7. The presence of micropyles in the shells of developing and undeveloped eggs of the ladybird beetle Harmonia axyridis (Coleoptera: Coccinellidae)
- Author
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Naoya OSAWA and Arata YOSHINAGA
- Subjects
coccinellidae ,harmonia axyridis ,hatchability ,infertile egg ,morphology ,scanning electron microscopy ,sibling cannibalism ,trophic egg ,Zoology ,QL1-991 - Abstract
In Hymenoptera and Heteroptera, the absence of micropyles is one criterion for categorizing an egg as trophic. Undeveloped eggs are observed in more than 90% of the egg clusters of the ladybird beetle Harmonia axyridis Pallas. Traditionally, these undeveloped eggs are regarded as "trophic eggs." The surfaces of the eggs of H. axyridis were examined using scanning electron microscopy and the presence of micropyles in the shells of developing and undeveloped eggs determined. Micropyles are circularly distributed around the top of eggs and present in both developing and undeveloped eggs. The number of micropyles in the shells of developing and undeveloped eggs did not differ significantly. Our results indicate that the undeveloped eggs of H. axyridis have micropyles, suggesting that the mechanisms regulating the production of undeveloped eggs in H. axyridis differ from those resulting in the production of trophic eggs by Hymenoptera and Heteroptera.
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- 2009
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8. Sympatric coexistence of sibling species Harmonia yedoensis and H. axyridis (Coleoptera: Coccinellidae) and the roles of maternal investment through egg and sibling cannibalism
- Author
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Naoya OSAWA and Kazunori OHASHI
- Subjects
coccinellidae ,coexistence ,harmonia axyridis ,harmonia yedoensis ,sibling cannibalism ,sibling species ,Zoology ,QL1-991 - Abstract
The sibling species H. yedoensis Takizawa coexists sympatrically and simultaneously with H. axyridis only on pine trees in Japan. To elucidate the mechanisms enabling coexistence of these two sympatric sibling species, a laboratory experiment was performed that focused on differences in their maternal investment through eggs and the role of sibling cannibalism. The egg size (volume) of H. yedoensis was 24.91% larger than that of H. axyridis. Cluster size in H. axyridis was significantly larger than that in H. yedoensis; however, the total number of eggs and oviposition cost (by volume) per female in H. yedoensis were not significantly different from those in H. axyridis, although total number of clusters tended to be slightly higher in H. yedoensis than in H. axyridis. The percentage of undeveloped eggs per cluster in H. yedoensis was not significantly different from that in H. axyridis, whereas the percentage of developed eggs with delayed hatching per cluster was significantly larger in H. yedoensis than in H. axyridis. Moreover, the cost of sibling cannibalism per hatched larval cluster in H. yedoensis (worth 4.43 sibling eggs) was 3.36 times larger than that in H. axyridis.Therefore, maternal investment through egg and sibling cannibalism in developed eggs with delayed hatching are more intense in H. yedoensis than in H. axyridis, implying a higher larval survival rate through higher ability of prey capturing at the first instar. The results in this study suggest that the higher survival rate and accelerated development in H. yedoensis by the two maternal investments, i.e., a large egg and intense sibling cannibalism of developed eggs with delayed hatching, may play an important role in sympatric coexistence with the aggressive aphidophagous ladybird beetle H. axyridis.
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- 2008
- Full Text
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9. The effect of prey availability on ovarian development and oosorption in the ladybird beetle Harmonia axyridis (Coleoptera: Coccinellidae)
- Author
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Naoya OSAWA
- Subjects
asymmetry ,harmonia axyridis ,coccinellidae ,energy storage ,oosorption ,ovarian development ,oviposition strategy ,population dynamics ,predator ,Zoology ,QL1-991 - Abstract
The ladybird beetle Harmonia axyridis Pallas was investigated under laboratory conditions to clarify the relationship between food abundance or scarcity and ovarian development or oosorption. Four conditions were used: (1) fully fed for 24 h, (2) 24-h starvation, (3) 48-h starvation, and (4) 24-h starvation followed by 24-h re-feeding. Body length and initial body weight were not significantly related to the number of ovarioles per female. Both starvation conditions significantly increased the percentage of oosorptive individuals and ovarioles per female, and significantly decreased the percentage of mature ovarioles per female. Re-feeding for 24 h after a 24-h starvation resulted in a significantly higher percentage of mature ovarioles per female; however, the percentage of mature ovarioles remained lower than in the fully fed condition. Oosorption mainly occurred during the intermediate developmental stage of the ovarioles. The rates of ovarian development and oosorption in predatory H. axyridis were much faster compared with those in herbivorous ladybird beetles. Body length, initial body weight, and the number of ovarioles were significantly correlated with the number of eggs laid during the last 24 h of each experimental condition. From an analysis of the weight loss and the number of eggs laid during the last 24 h of each experimental condition, it appears that the realized weight of the eggs may be directly determined by the amount of food digested by the adult. The ovarian development and oosorption were asymmetric in the right and left ovaries. These may be important strategies for oviposition in H. axyridis, because selective provision of maturing ovarioles in the right or left ovary with digested nutrients would favor their development. In addition, the energy loss through oosorption during the intermediate developmental stage of oocytes would be less than the energy loss resulting from the resorption of mature oocytes. Therefore, one role of the ovary in H. axyridis, in addition to egg production, might be as a kind of energy storage system for increasing reproductive success. An immediate start of ovarian development under favorable feeding conditions and rapid oosorption during food scarcities may be an adaptive ovipositional and survival strategy for female adults of H. axyridis in response to heterogeneous and fluctuating resource conditions.
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- 2005
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10. The influence of female oviposition strategy on sibling cannibalism in the ladybird beetle Harmonia axyridis (Coleoptera: Coccinellidae)
- Author
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Naoya OSAWA
- Subjects
coccinellidae ,egg fertility ,harmonia axyridis ,oviposition strategy ,sibling cannibalism ,Zoology ,QL1-991 - Abstract
I hypothesized that sibling cannibalism is one of maternal investment in that a female controls sibling cannibalism. To test the hypothesis, I conducted a laboratory experiment and field observations to investigate sibling cannibalism in relation to cluster size and cluster site in the ladybird beetle, Harmonia axyridis Pallas. In the laboratory experiment, cluster size significantly affected the number of cannibalized eggs per cluster (R2 = 0.516), while cluster size was significantly affected by the oviposition interval. Furthermore, there was a marginally significant positive relationship between cluster size and the percentage of sibling cannibalism per cluster. In the field, cluster size and the direct distance from a cluster site to an aphid colony (an indicator of intensity of non-sibling cannibalism) significantly affected the number of cannibalized eggs per cluster (R2 = 0.472). Furthermore, there was a significant positive relationship between the direct distance from a cluster to the nearest aphid colony and cluster size. However, there was not a significant relationship between the distance and the percentage of sibling cannibalism. These results may be caused by the weakness of the female's power to control sibling cannibalism. Thus, a female H. axyridis controls cluster size through the intensity of non-sibling cannibalism, which may be one of oviposition strategies in this species.
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- 2003
- Full Text
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11. Increase in male reproductive success and female reproductive investment in invasive populations of the harlequin ladybird Harmonia axyridis.
- Author
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Guillaume J M Laugier, Gilles Le Moguédec, Ashraf Tayeh, Anne Loiseau, Naoya Osawa, Arnaud Estoup, and Benoît Facon
- Subjects
Medicine ,Science - Abstract
Reproductive strategy affects population dynamics and genetic parameters that can, in turn, affect evolutionary processes during the course of biological invasion. Life-history traits associated with reproductive strategy are therefore potentially good candidates for rapid evolutionary shifts during invasions. In a series of mating trials, we examined mixed groups of four males from invasive and native populations of the harlequin ladybird Harmonia axyridis mating freely during 48 hours with one female of either type. We recorded the identity of the first male to copulate and after the 48 h-period, we examined female fecundity and share of paternity, using molecular markers. We found that invasive populations have a different profile of male and female reproductive output. Males from invasive populations are more likely to mate first and gain a higher proportion of offspring with both invasive and native females. Females from invasive populations reproduce sooner, lay more eggs, and have offspring sired by a larger number of fathers than females from native populations. We found no evidence of direct inbreeding avoidance behaviour in both invasive and native females. This study highlights the importance of investigating evolutionary changes in reproductive strategy and associated traits during biological invasions.
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- 2013
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12. Pollination ecology of the early-spring-blooming dioecious shrub Eurya japonica (Pentaphylacaceae)
- Author
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Midzuho Tatsuno, Masahiro Sueyoshi, and Naoya Osawa
- Subjects
Ecology ,Plant Science ,Ecology, Evolution, Behavior and Systematics - Abstract
While the majority of angiosperm plants have hermaphrodite flowers, where a single pollinator visit can achieve both pollen removal and deposition, 5%–6% of angiosperms, including zoophilous species, are dioecious, necessitating pollen transport from male plants to females. As such, dioecy is considered less adaptive under low-temperature conditions that tend to restrict or lower potential pollinator activity. Interestingly, however, a number of dioecious, zoophilous plants such as Eurya japonica Thunb. (Pentaphylacaceae) bloom in low-temperature seasons. This study made a quantitative assessment of flower visitors/pollinators of E. japonica blooming in early spring in central Japan. A total of 15 families in 4 orders of insects were recorded on both pistillate and staminate flowers of E. japonica, of which Diptera (Empididae and Chironomidae, in particular) and Hymenoptera were predominant regardless of site/year. Hymenopteran visitors were more active at higher temperatures, while dipterans were observed even at low temperatures. The fruiting rate and the number of seeds were greater at the site where dipteran visitors were more abundant. The present study suggests that the system of multi-taxa, Diptera-dominated pollination may play an important role in the reproductive ecology of dioecious plant species, in particular those flowering at low temperatures.
- Published
- 2023
13. The impact of bug management patterns on bug fixing: A case study of Eclipse projects.
- Author
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Masao Ohira, Ahmed E. Hassan, Naoya Osawa, and Ken-ichi Matsumoto
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- 2012
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14. Aggregation behaviors of young nymphs in Panesthia angustipennis spadica ( <scp>B</scp> laberidae)
- Author
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Hiroki Ito and Naoya Osawa
- Subjects
biology ,Kin recognition ,Insect Science ,Zoology ,Panesthia angustipennis ,biology.organism_classification ,Nymph ,Ecology, Evolution, Behavior and Systematics ,Blaberidae - Published
- 2021
15. Habitat generalization of a predatory ladybird, Harmonia yedoensis (Coleoptera: Coccinellidae), in an allopatric area with respect to its sibling species Harmonia axyridis
- Author
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Naoya Osawa, Suzuki Noriyuki, Junki Sugo, and Masaaki Ohata
- Subjects
0106 biological sciences ,Ecological niche ,geography ,geography.geographical_feature_category ,biology ,Ecology ,Range (biology) ,Harmonia ,Generalist and specialist species ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Harmonia axyridis ,010602 entomology ,Habitat ,Insect Science ,Archipelago ,Coccinellidae ,Ecology, Evolution, Behavior and Systematics - Abstract
In central Japan, Harmonia yedoensis is a specialist ladybird that is confined to pine tree habitats, whereas its sibling species Harmonia axyridis is a generalist that feeds on a wide range of aphid species in nature. Interestingly, H. axyridis is not distributed in the Ryukyu Archipelago, southern Japan. We hypothesized that the ecological niche of H. yedoensis should be wider in the Ryukyu Archipelago, where its competitor species in central Japan, H. axyridis, is absent. We undertook fieldwork and a survey of published works to examine habitat utilization by H. yedoensis in the Ryukyu Archipelago. We found that H. yedoensis adults in the Ryukyu Archipelago visited several kinds of deciduous trees, including wild tamarind, Chinese hibiscus, Taiwan cherry and Malayan banyan, as well as pine trees. These observations suggest that habitat generalization has occurred in H. yedoensis in the Ryukyu Archipelago, where it does not compete with H. axyridis.
- Published
- 2019
16. Beyond 'greening': which paradigms shape sustainable pest management strategies in the European Union?
- Author
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Naoya Osawa and Séverin Hatt
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0106 biological sciences ,Productivism ,Natural resource economics ,business.industry ,Biology ,010603 evolutionary biology ,01 natural sciences ,Ecosystem services ,010602 entomology ,Incentive ,Agriculture ,Animal ecology ,Insect Science ,Green growth ,media_common.cataloged_instance ,European union ,business ,Agronomy and Crop Science ,Common Agricultural Policy ,media_common - Abstract
Various strategies exist to manage agriculture pests with few or without conventional pesticides. Farmers can rely on ecosystem services delivered by agro-biodiversity or use biotechnologies and biological plant protection products (PPP). Integrated Pest Management (IPM) has developed as an approach that combines these tools. The adoption of IPM has been supported by the European Union (EU) in the recent years. In parallel, EU Common Agricultural Policy (CAP) has strengthened its agri-environmental incentives to further protect biodiversity in agricultural landscapes. These evolutions have been presented as the “greening” of the CAP. We argue that this “greening” aims at strengthening agricultural competitiveness while preserving biodiversity. Hence, we suggest that the EU policy is entrenched in a green productivism paradigm, which objective is to produce more with less to achieve green growth within capitalism. Nonetheless, this worldview does not content all European farmers. We explain that those who reject productivism treasure a sufficiency paradigm by refusing the use of biotechnologies and biological PPP to consolidate their autonomy, especially regarding markets. By producing enough, and not more with less, they achieve complementary objectives, notably meeting their consumers’ expectations and perpetuating their productive resources. We based our arguments on discussions with farmers, participation to various meetings between 2013 and 2017 where these issues were debated, and the analyses of the EU policies, scientific studies, as well as the farmer unions’ and the companies’ publications.
- Published
- 2019
17. The role of Perilla frutescens flowers on fitness traits of the ladybird beetle Harmonia axyridis
- Author
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Naoya Osawa and Séverin Hatt
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0106 biological sciences ,biology ,media_common.quotation_subject ,fungi ,Longevity ,Biological pest control ,food and beverages ,Zoology ,biology.organism_classification ,Fecundity ,010603 evolutionary biology ,01 natural sciences ,Harmonia axyridis ,Predation ,010602 entomology ,Animal ecology ,Insect Science ,Coccinellidae ,Agronomy and Crop Science ,Predator ,media_common - Abstract
Predaceous ladybird beetles are known to consume alternative foods from flowers, especially when prey is scarce. Flower-rich semi-natural habitats in agroecosystems generally host a diversity of natural enemies, including predaceous ladybird beetles, suggesting that the availability of flowers may have a positive role in their fitness traits. In this study, we test whether feeding on flowers of Perilla frutescens (Lamiaceae) increases longevity and fecundity in Harmonia axyridis Pallas (Coleoptera: Coccinellidae). The longevity of H. axyridis females and males fed with five flowers was significantly greater than those fed with one flower and in the control group (no food), although the provision of flowers had no positive effect on the increase of body weight in males and females. The number of eggs and oviposition frequency in H. axyridis fed with flowers plus prey, as well as with prey only, were significantly larger than those fed with only flowers, whereas no significant difference was observed between individuals fed with the mixed diet and those with only prey. However, on the first day of the diet assignment, the number of eggs from individuals with the mixed diet was significantly higher than of those with only prey and those with only flowers. The results show that flowers of P. frutescens, mixed with prey, have a positive effect on H. axyridis survival and early reproduction, suggesting that flowers may play an important role in increasing fitness in H. axyridis. The possibility of P. frutescens sown in fields to support populations of the predator toward conservation biological control is discussed.
- Published
- 2019
18. Aromatic plants of East Asia to enhance natural enemies towards biological control of insect pests. A review
- Author
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Frédéric Francis, Qingxuan Xu, Naoya Osawa, and Séverin Hatt
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Agroforestry ,Insect Science ,media_common.quotation_subject ,Biological pest control ,Aromatic plants ,Vote counting ,East Asia ,Natural enemies ,Insect ,Biology ,media_common - Published
- 2019
19. A field study of the colony composition of the wood-feeding cockroach Panesthia angustipennis spadica (Blattodea: Blaberidae)
- Author
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Hiroki Ito and Naoya Osawa
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0106 biological sciences ,0301 basic medicine ,Entomology ,Cockroach ,biology ,Zoology ,biology.organism_classification ,01 natural sciences ,Blaberidae ,010602 entomology ,03 medical and health sciences ,030104 developmental biology ,Blattodea ,Insect Science ,biology.animal ,Instar ,Composition (visual arts) ,Panesthia angustipennis ,Nymph - Abstract
This paper presents a method with accuracy to estimate instars for insects which have large number of instars, especially at long growth period. We clarified the colony composition of the wood-feeding cockroach Panesthia angustipennis spadica Shiraki (Blaberidae) in a field, estimating the instars of field-collected individuals through a cluster analysis using field and laboratory data. Overall, 84.8% sampled units contained multiple individuals, and the largest colony consisted of 65 individuals. The colonies were composed of adults and nymphs (43.5%), or nymphs without adults (52.2%). The number of instars in this species was estimated as ca. ten. Furthermore, some colonies contained an adult pair and nymphs at multiple developmental stages, whereas other colonies contained only small nymphs (estimated instars 1–3). These results demonstrate that the social structure of P. angustipennis spadica varies widely, and that colonies containing both adults and nymphs may indicate the origin of subsociality in cockroaches.
- Published
- 2018
20. Identification of flower functional traits affecting abundance of generalist predators in perennial multiple species wildflower strips
- Author
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Thomas Chevalier Mendes Lopes, Julien Piqueray, Frédéric Francis, Pierre Mouchon, Roel Uytenbroeck, Arnaud Monty, Naoya Osawa, and Séverin Hatt
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0106 biological sciences ,Eupeodes corollae ,Propylea quatuordecimpunctata ,Ecology ,Wildflower ,biology ,Neuroptera ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Coccinella septempunctata ,010602 entomology ,Insect Science ,Episyrphus balteatus ,Agronomy and Crop Science ,Chrysopidae ,Ecology, Evolution, Behavior and Systematics ,Chrysoperla carnea - Abstract
In agricultural fields, wildflower strips can be sown to enhance conservation biological control of insect pests. However, issues remain regarding the composition of flower mixtures to effectively attract and support large communities of natural enemies. Trait-based approaches are promising for this purpose. In the present study, conducted in an agricultural field of Belgium in 2014 and 2015, 15 flower mixtures were considered to explore the relation between the abundance of trapped generalist predators (i.e. lacewings [Neuroptera: Chrysopidae], ladybeetles [Coleoptera: Coccinellidae] and hoverflies [Diptera: Syrphidae]) and the community-weighted means of seven flower traits. Through a redundancy analysis, it was found that the presence/absence of flower ultra-violet pattern and the morphology of the corolla (that determines the accessibility of floral resources) were the traits that significantly affected the abundance of the generalist predators in the flower mixtures. The ladybeetles Harmonia axyridis and Propylea quatuordecimpunctata as well as the lacewings Chrysoperla carnea were more abundant in mixtures with a high cover of flowers showing an ultra-violet pattern, while the opposite was observed for the ladybeetle Coccinella septempunctata. As for hoverflies, Episyrphus balteatus and Eupeodes corollae were more abundant in mixtures with a high cover of flowers with open nectar. These results bring new knowledge regarding how a range of natural enemy species reacts to flower cues in diversified plant communities and should help in elaborating flower mixtures that enhance conservation biological control.
- Published
- 2018
21. The effects of aggregation on survival and growth rate in the wood-feeding cockroachPanesthia angustipennis spadica(Blaberidae)
- Author
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Naoya Osawa and Hiroki Ito
- Subjects
0106 biological sciences ,Cockroach ,biology ,Ecology ,Zoology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Blaberidae ,Predation ,010602 entomology ,Insect Science ,biology.animal ,Instar ,Nymph ,Xylophagy ,Moulting ,Paternal care ,Ecology, Evolution, Behavior and Systematics - Abstract
The wood-feeding cockroach Panesthia angustipennis spadica Shiraki (Blaberidae) is a gregarious species, and its groups containing both nymphs and adults have often been observed in the field. To clarify the effects of aggregation with a parent and siblings on nymphal development in P. angustipennis spadica, we raised nymphs of this species in the laboratory under the following three experimental categories: (a) aggregate with a female adult; (b) aggregate without a female adult; and (c) solitary. Survival rates did not significantly differ among the three categories. Unexpectedly, our results clearly showed that nymphs raised in aggregates with a female adult were smaller, lighter, and reached a lower instar than those raised without a female adult. These results indicate that the presence of a female adult does not positively affect nymphal development; i.e. there may be no direct parental care in this species as indicated by previous studies. Moreover, solitary nymphs grew faster and larger than nymphs in aggregates, showing that the aggregation with siblings also has no positive effect on nymphal development. Thus, it seems likely that external factors, e.g. predation and environmental conditions, may drive aggregating behavior in P. angustipennis spadica.
- Published
- 2017
22. Horizontal niche differentiation of ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) within the standing trunk of Quercus serrata
- Author
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Naoya Osawa and Hiroaki Iidzuka
- Subjects
0106 biological sciences ,biology ,Range (biology) ,Niche ,Niche differentiation ,Forestry ,biology.organism_classification ,Quercus serrata ,010603 evolutionary biology ,01 natural sciences ,Trunk ,Fagaceae ,Plant ecology ,010602 entomology ,Botany ,Ambrosia - Abstract
Niche differentiation, in terms of time and space, has been reported within a community of ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) in a tree trunk. Two platypodid ambrosia beetles, Platypus quercivorus (Murray) and Platypus calamus Blandford, utilize a similar height range with respect to the Quercus serrata Murray (Fagaceae) trunk. The sapwood and heartwood (i.e., wood types) are known to differ in their physical and chemical characteristics. The objective of this study was to determine the differences among ambrosia beetles, in terms of wood type preferences, in a Q. serrata tree trunk. We analyzed the horizontal distribution patterns of ambrosia beetles within two mature Q. serrata tree trunks. Platypus calamus and the other ambrosia beetles [P. quercivorus, Ambrosiodmus lewisi (Blandford), Ambrosiophilus atratus Eichhoff, and Xyleborus sp.] showed different horizontal distribution patterns within the wood. The former tended to utilize the heartwood, whereas the latter utilized the sapwood. These results suggest that the wood type can be regarded as one of the niche dimensions of ambrosia beetles in a Q. serrata trunk.
- Published
- 2016
23. Gallery diameter of ambrosia beetles (Coleoptera: Scolytidae, Platypodidae) and insect fauna in Quercus serrata (Fagales: Fagaceae) suffering from Japanese oak wilt
- Author
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Naoya Osawa, Hideaki Goto, and Hiroaki Iidzuka
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0106 biological sciences ,Zopheridae ,biology ,Fauna ,Ambrosia beetle ,biology.organism_classification ,Quercus serrata ,010603 evolutionary biology ,01 natural sciences ,Fagaceae ,010602 entomology ,Cossoninae ,Insect Science ,Curculionidae ,Botany ,Mycetophagidae - Abstract
We dissected the trunk of a Quercus serrata Murray tree that had suffered from Japanese oak wilt, measured the gallery diameters of ambrosia beetles, and recorded the related insect fauna in the galleries of ambrosia beetles. In total, 545 individuals of nine species were captured from 494 galleries; these belonged to nine species [Cossoninae sp. (Curculionidae), Litargus japonicus Reitter (Mycetophagidae), Platypus calamus Blandford (Platypodidae), Platypus quercivorus (Murayama) (Platypodidae), Ambrosiodmus lewisi (Blandford) (Scolytidae), Ambrosiophilus atratus Eichhoff (Scolytidae), Xyleborus sp. (Scolytidae), Bitoma siccana Pascoe (Zopheridae), and Gempylodes ornamentalis (Reitter) (Zopheridae)]. The diameter of the gallery entrance on the surface of a debarked log may serve as a cue for species estimation of major ambrosia beetles in Q. serrata trees suffering from Japanese oak wilt in this study area. From the relationships between the body width and the gallery diameter, the distribution pattern within the tree, and the taxonomical analogy, a zopherid species, G. ornamentalis, was inferred as a possible predator and/or parasitoid of a causal agent in Japanese oak wilt, P. quercivorus.
- Published
- 2016
24. Wood-boring beetles (Coleoptera: Scolytidae, Platypodidae) captured in ethanol-baited traps in a natural forest in Japan
- Author
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Hideaki Goto, Naoya Osawa, Michimasa Yamasaki, and Hiroaki Iidzuka
- Subjects
0106 biological sciences ,Entomology ,education.field_of_study ,biology ,Ecology ,Xyleborini ,Natural forest ,Population ,Community structure ,Trapping ,Seasonality ,biology.organism_classification ,medicine.disease ,010603 evolutionary biology ,01 natural sciences ,010602 entomology ,Diversity index ,Insect Science ,medicine ,education - Abstract
We mainly examined the community structure and seasonal population trends of scolytid and platypodid species captured via ethanol-baited traps in a natural cool-temperate forest in Japan. The scolytid species in the tribe Xyleborini represented more than 70 % of individuals captured in ethanol-baited traps, although the platypodid species could be abundant in this study area. These results indicate that the scolytid species in tribe Xyleborini might have higher sensitivity to ethanol-baited traps than others and the ethanol-baited trapping method could target the limited number of scolytid and platypodid species. Therefore, analysis based only on the ethanol-baited trapping method may lead to misunderstanding the community structure of scolytid and platypodid species. The analysis of the seasonal changes in number of scolytid and platypodid species, using a generalized linear model (GLM) showed that the ethanol-baited traps appeared to function more effectively in spring than in other seasons. Hence, the trapping season should be considered when analyzing the data obtained from ethanol-baited trapping census, especially with scolytid and platypodid species.
- Published
- 2016
25. Geographic variation of color polymorphism in two sibling ladybird species,Harmonia yedoensisandH. axyridis(Coleoptera: Coccinellidae)
- Author
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Naoya Osawa and Suzuki Noriyuki
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biology ,Ecology ,Sympatric speciation ,Insect Science ,Melanism ,Character displacement ,Coccinellidae ,Harmonia ,Cline (biology) ,biology.organism_classification ,Generalist and specialist species ,Ecology, Evolution, Behavior and Systematics ,Black spot - Abstract
Geographical variation of elytra color pattern in two sibling ladybird species, Harmonia yedoensis and H. axyridis (Coleoptera: Coccinellidae), was examined. The two species are distributed sympatrically in central Japan; however, only H. yedoensis and H. axyridis occur in the Ryukyu Islands (southern Japan) and Hokkaido island (northern Japan), respectively. The frequency of elytra color patterns was significantly different between the two species in all sympatric locations and our results were inconsistent with the classical theory on Mullerian mimicry. The most dominant pattern of H. axyridis was the least dominant of H. yedoensis in all sympatric populations. Furthermore, the frequency of the non-melanic form (red ground color with or without black spots) increased towards the south in H. yedoensis. This tendency was in contrast to the known geographical cline in H. axyridis in which the melanic form (black ground color with red spots) was gradually displaced with the non-melanic form northwards in the Japanese archipelago. We discuss possible selective factors including predator avoidance, thermal adaptation and reproductive character displacement, all of which might contribute to the maintenance of the color polymorphism in the two Harmonia species.
- Published
- 2015
26. Prevalence of male-killer in a sympatric population of two sibling ladybird species, Harmonia yedoensis and Harmonia axyridis (Coleoptera: Coccinellidae)
- Author
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Naoya Osawa, Suzuki Noriyuki, and Yuichi Kameda
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coleoptera ,h. yedoensis ,maternally inherited bacteria ,Population ,Foraging ,Zoology ,Harmonia ,Predation ,sibling species ,education ,Hatchling ,harmonia axyridis ,education.field_of_study ,early male-killing ,biology ,Ecology ,sex ratio ,biology.organism_classification ,Harmonia axyridis ,aphidophagous ladybird ,sibling cannibalism ,QL1-991 ,Insect Science ,coccinellidae ,embryonic structures ,Coccinellidae ,Sex ratio ,maternal investment - Abstract
In predatory ladybirds male embryos in clutches of eggs infected with male-killing bacterial endosymbionts do not hatch and are consumed by female hatchlings. Moreover, it is predicted that infection with male-killing bacteria should be prevalent in a ladybird population if the fitness advantage to female ladybirds due to the resulting reallocation of resources is high. We compared male-killer bacterial prevalence in two sibling species of the ladybird genus Harmonia that use different host ranges. Harmonia yedoensis feeds mostly on the highly elusive pine aphid and its hatchlings can greatly enhance their ability to capture prey and thus their survival by consuming un-hatched eggs in the clutch. In contrast, Harmonia axyridis feeds on a wide range of prey and consumption of un-hatched eggs by the hatchlings does not necessarily increase their foraging success. In the study area where these two species of ladybird occur sympatrically 14 of the 22 females of H. yedoensis (64%) laid clutches of eggs of which approximately only a half hatched and did not produce male offspring, whereas only one of 12 of the females of H. axyridis (8%) exhibited symptoms indicating infection with male-killing bacteria. In the H. yedoensis that exhibited symptoms of being infected with male-killing bacteria, the total allocation of resources to each hatchling, which was provided by laying larger eggs and eating the un-hatched eggs in the clutch, was considerable. These results suggest that the difference in the prevalence of infection with male-killing bacteria in these two species of ladybird may reflect differences in the quality of their prey and their foraging behaviour.
- Published
- 2014
27. Effects of intraguild predation on the life history traits and progeny of the ladybird beetle Hippodamia variegata.
- Author
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TOOSI, Mehdi, RASEKH, Arash, and Naoya OSAWA
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LADYBUGS ,COTTON aphid ,LIFE history theory ,PREDATION ,BIOLOGICAL pest control agents ,APHIDS - Abstract
The simultaneous use of multiple biological control agents requires sufficient information of intraguild predation (IGP). In this work, the prey preferences of immature stages of the ladybird beetle Hippodamia variegata (Goeze) (Coleoptera Coccinellidae) for non-parasitized and parasitized adults of Aphis gossypii Glover (Hemiptera Aphididae) by the parasitoid wasp Lysiphlebus fabarum (Marshall) (Hymenoptera Braconidae) were investigated at the laboratory choice experiments. Moreover, the effects of these different feeding regimes of the immature stages were determined for the life history traits of emerging H. variegata and its progeny. Results revealed that the second and third instar larvae of H. variegata revealed no preference for the non-parasitized and parasitized aphids. The immature developmental time of H. variegata fed on the parasitized aphids was significantly shorter than those fed on the non-parasitized aphids; however, the weight of the emerged adults did not differ significantly. Contrary to this, in the next generation, the egg and hatched larval size of H. variegata fed on the parasitized aphids were significantly larger than those fed on the non-parasitized aphids, whereas the mean and total number of eggs laid by H. variegata fed on the parasitized aphids was significantly smaller than for those fed on the non-parasitized aphids. The feeding regimes at maternal rearing conditions revealed a significant effect on the progeny, as the weight of the emerging male and female adults increased. Combined with the simultaneous application of the two biological control agents, the negative effects resulting from feeding on the IG prey, L. fabarum, may be compensated by the fitness gained by the IG predator, H. variegata, and its progeny. Hence, the asymmetric IGP may not have a negative impact on the biological control of A. gossypii. [ABSTRACT FROM AUTHOR]
- Published
- 2019
28. Habitat generalization of a predatory ladybird, Harmonia yedoensis (Coleoptera: Coccinellidae), in an allopatric area with respect to its sibling species Harmonia axyridis.
- Author
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Suzuki NORIYUKI, Junki SUGO, Masaaki OHATA, and Naoya OSAWA
- Subjects
HARMONIA axyridis ,LADYBUGS ,BEETLES ,ECOLOGICAL niche ,LEAD tree ,STAPHYLINIDAE ,PREDATORY animals - Abstract
In central Japan, Harmonia yedoensis is a specialist ladybird that is confined to pine tree habitats, whereas its sibling species Harmonia axyridis is a generalist that feeds on a wide range of aphid species in nature. Interestingly, H. axyridis is not distributed in the Ryukyu Archipelago, southern Japan. We hypothesized that the ecological niche of H. yedoensis should be wider in the Ryukyu Archipelago, where its competitor species in central Japan, H. axyridis, is absent. We undertook fieldwork and a survey of published works to examine habitat utilization by H. yedoensis in the Ryukyu Archipelago. We found that H. yedoensis adults in the Ryukyu Archipelago visited several kinds of deciduous trees, including wild tamarind, Chinese hibiscus, Taiwan cherry and Malayan banyan, as well as pine trees. These observations suggest that habitat generalization has occurred in H. yedoensis in the Ryukyu Archipelago, where it does not compete with H. axyridis. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
29. Ambrosia beetles (Curculionidae: Scolytinae and Platypodinae) onFagus crenata Blume: community structure, seasonal population trends and resource utilization patterns
- Author
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Hideaki Goto, Naoya Osawa, Hiroaki Iidzuka, and Michimasa Yamasaki
- Subjects
education.field_of_study ,biology ,Ecology ,media_common.quotation_subject ,Fagus crenata ,Population ,Platypodinae ,Insect ,biology.organism_classification ,Insect Science ,Curculionidae ,biology.animal ,Ambrosia ,education ,Platypus ,Ecology, Evolution, Behavior and Systematics ,Sex ratio ,media_common - Abstract
Ambrosia beetles (many Scolytinae and all Platypodinae) are one of the most important insect pests for forestry worldwide, but little is known about the community structure of ambrosia beetles in terms of their vertical variations and resource utilization. We clarified the community structure and seasonal population trends of ambrosia beetles on 11 living and three newly dead Fagus crenata Blume trees using individual tube traps placed up to 10 m high from May to November in 2007 and 2008. We captured seven scolytine species (Ambrosiodmus lewisi (Blandford), Euwallacea validus (Eichhoff), Trypodendron proximum (Niisima), Xyleborinus saxeseni (Ratzeburg), Xyleborus atratus Eichhoff, Xylosandrus brevis (Eichhoff) and Xylosandrus germanus (Blandford)) and three platypodine species (Crossotarsus niponicus Blandford, Platypus hamatus Blandford and Platypus severini Blandford). The ambrosia beetles were suggested to breed at species-specific height ranges, with the equal host resource use per individual among the species. Of the three major species, C. niponicus, P. hamatus and P. severini, two (C. niponicus and P. hamatus) had male-biased sex ratios, which is considered a reproductive strategy to increase maternal fitness. Morphological characteristics of the mandibles may play an important role in the difference of sex roles on reproduction in the three major species.
- Published
- 2013
30. The harlequin ladybird, Harmonia axyridis: global perspectives on invasion history and ecology
- Author
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Alexandra Magro, Artur Gil, A.J.M. Loomans, Cang Hui, Katie M. Murray, Sandra Viglášová, Paul S. van Wielink, Axel Vandereycken, Arnaud Estoup, Susana Clusella-Trullas, Benoit Facon, Annette Herz, May-Guri Saethre, Zdenka Martinkova, Richard Comont, Isabel Borges, Dirk Maes, Sergey K. Ryndevich, Thomas Guillemaud, Helen E. Roy, António O. Soares, Marina J. Orlova-Bienkowskaja, Mary M. Gardiner, Alexander Ok Lukashuk, Tim Adriaens, William D. Hutchison, Ingrid A. Minnaar, Patrick De Clercq, John J. Sloggett, Peter M. J. Brown, Alois Honek, Marc Kenis, Audrey A. Grez, Hans Peter Ravn, Tania Zaviezo, Nick Berkvens, Wolfgang Rabitsch, Danny Haelewaters, Riaan Stals, Zihua Zhao, Ján Kulfan, John E. Losey, Peter Zach, Andy G. Howe, Eric Lombaert, I. A. Zakharov, Lori Lawson Handley, Oldrich Nedved, Robert L. Koch, Steph L. Rorke, Matthew C. Tinsley, Gabriele Rondoni, René Eschen, Naoya Osawa, Edward W. Evans, Gilles San Martin, Centre for Ecology and Hydrology [Wallingford] (CEH), Natural Environment Research Council (NERC), Anglia Ruskin University (ARU), Research Institute for Nature and Forest (INBO), Research Institute for Agricultural, Fisheries and Food (ILVO), University of the Azores, Centre for Ecology, Evolution and Environmental Changes (cE3c) / Azorean Biodiversity Group and Universidade dos Açores, Departamento de Ciências e Engenharia do Ambiente, Açores, Stellenbosch University, Centre for Invasion Biology, Department of Botany and Zoology, Bumblebee Conservation Trust, Universiteit Gent = Ghent University [Belgium] (UGENT), Department of Crop Protection, Centre for Agricultural and Biosciences International Europe - Switzerland (CABI Europe - Switzerland), Centre de Biologie pour la Gestion des Populations (UMR CBGP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Utah State University (USU), Ohio State University [Columbus] (OSU), Ohio Agricultural Research and Development Center, Universidad de Chile = University of Chile [Santiago] (UCHILE), Institut Sophia Agrobiotech (ISA), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut National de la Recherche Agronomique (INRA), Department of Organismic and Evolutionary Biology [Cambridge] (OEB), Harvard University [Cambridge], Julius Kühn-Institut - Federal Research Centre for Cultivated Plants (JKI), Crop Res Inst, Div Crop Genet & Breeding, Prague, Czech Republic, Partenaires INRAE, Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Centre for Invasion Biology, Department of Mathematical Sciences, Stellenbosch University, University of Minnesota System, Institute of Forest Ecology - SAS, University of Hull [United Kingdom], National Plant Protection Organization (NPPO), Cornell University [New York], Berezinskiy Biosphere Reserve, Belarus, Evolution et Diversité Biologique (EDB), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, University of Stirling, Department of Biological and Environmental Sciences, University of Stirling, Walloon Agricultural Research Centre, Department of Botany and Zoology, Centre of Excellence for Invasion Biology, University of South Bohemia, Institute of Entomology [České Budějovice] (BIOLOGY CENTRE CAS), Biology Centre of the Czech Academy of Sciences (BIOLOGY CENTRE CAS), Czech Academy of Sciences [Prague] (CAS)-Czech Academy of Sciences [Prague] (CAS), A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences [Moscow] (RAS), Kyoto University [Kyoto], Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Environment Agency Austria, Department of Agricultural, Food and Environmental Sciences, University of Perugia (DSA3), Università degli Studi di Perugia (UNIPG), The paper had its origin at a workshop on 'Drivers, impacts, mechanisms and adaptation in insect invasions' hosted by the DST-NRF Centre of Excellence for Invasion Biology in Stellenbosch, South Africa, in November 2014. Additional financial support was provided by HortGro, the National Research Foundation of South Africa, Stellenbosch University, and SubTrop. We thank all our collaborators, and particularly the volunteer community, who have contributed to research around the world on H. axyridis. The number of references included reflects the range of inspiring studies on H. axyridis from so many people-we look forward to new and continued collaborations in the future. We are grateful to the editors of this special issue for inviting this review and providing an opportunity to explore ideas through the 'Invasive Insects Workshop funding (NRF South Africa, CIB)'. We also thank the anonymous reviewers for all their useful comments and reflections. The UK Ladybird Survey and associated coauthors are supported by the Biological Records Centre (part of the Centre for Ecology & Hydrology), which receives support from both the Natural Environment Research Council and the Joint Nature Conservation Committee. The IOBC WPRS and Global Working Groups 'Benefits and Risks of Exotic Biological Control Agents' and the COST Action TD1209 'Alien Challenge' have facilitated discussions and collaborations on H. axyridis. This study was supported by the French Agropolis Fondation (Labex Agro-Montpellier, BIOFIS Project Number 1001-001) and by a grant from the ERA-Net BiodivERsA, with the national funders ANR (France), DFG (Germany) and BELSPO (Belgium), as part of the 2012-2013 BiodivERsA call for research proposals. Support has been also received from FONDECYT 1140662 (Chile). The study of M.J. Orlova-Bienkowskaja and I. A. Zakharov was supported by Russian Science Foundation, Project No. 16-16-00079. Gabriele Rondoni acknowledges financial support from Fondazione Cassa di Risparmio di Perugia. Riaan Stals acknowledges funding from the Department of Science and Technology, South Africa. The research of Peter Zach and colleagues was funded by the project VEGA 2/0035/13 and VEGA 2/0052/15. A. Honek and Z. Martinkova were supported by grants GACR 14-26561S and COST CZ LD14084. Research in Switzerland is funded by the Swiss Federal Office for the Environment. Hans Peter Ravn was supported by the Villum Foundation. Danny Haelewaters acknowledges funding from the David Rockefeller Center for Latin American Studies at Harvard University and from the Mycological Society of America., Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, Research Institute for Nature and Forest, Institut Sophia Agrobiotech [Sophia Antipolis] (ISA), Institut National de la Recherche Agronomique (INRA)-Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Julius Kühn Institute (JKI), CABI Europe Switzerland, Universität der Bundeswehr München [Neubiberg], Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Grad Sch Agr, Lab Forest Ecol, Department of Biodiversity and Nature Conservation, NEMOD Biotherapeutics GmbH & Co. KG, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile (UC), RS: FSE MSP, and Maastricht Science Programme
- Subjects
0106 biological sciences ,Range (biology) ,Ecology (disciplines) ,ADALIA-BIPUNCTATA ,Population ,Biodiversity ,INTRAGUILD PREDATION ,Generalist and specialist species ,NATURAL ENEMIES ,010603 evolutionary biology ,01 natural sciences ,Ecology and Environment ,1ST RECORD ,Competitive interactions ,MYZUS-PERSICAE HOMOPTERA ,education ,Ecology, Evolution, Behavior and Systematics ,ComputingMilieux_MISCELLANEOUS ,Apex predator ,education.field_of_study ,APHIS-GLYCINES ,Ecology ,biology ,PALLAS COLEOPTERA-COCCINELLIDAE ,Biocontrol ,15. Life on land ,biology.organism_classification ,Harmonia axyridis ,010602 entomology ,MULTICOLORED ASIAN LADYBIRD ,Coccinellidae ,Invasion history ,Species traits ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,BEETLE COLEOPTERA ,BIOLOGICAL-CONTROL ,Intraguild predation - Abstract
International audience; The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is native to Asia but has been intentionally introduced to many countries as a biological control agent of pest insects. In numerous countries, however, it has been introduced unintentionally. The dramatic spread of H. axyridis within many countries has been met with considerable trepidation. It is a generalist top predator, able to thrive in many habitats and across wide climatic conditions. It poses a threat to biodiversity, particularly aphidophagous insects, through competition and predation, and in many countries adverse effects have been reported on other species, particularly coccinellids. However, the patterns are not consistent around the world and seem to be affected by many factors including landscape and climate. Research on H. axyridis has provided detailed insights into invasion biology from broad patterns and processes to approaches in surveillance and monitoring. An impressive number of studies on this alien species have provided mechanistic evidence alongside models explaining large-scale patterns and processes. The involvement of citizens in monitoring this species in a number of countries around the world is inspiring and has provided data on scales that would be otherwise unachievable. Harmonia axyridis has successfully been used as a model invasive alien species and has been the inspiration for global collaborations at various scales. There is considerable scope to expand the research and associated collaborations, particularly to increase the breadth of parallel studies conducted in the native and invaded regions. Indeed a qualitative comparison of biological traits across the native and invaded range suggests that there are differences which ultimately could influence the population dynamics of this invader. Here we provide an overview of the invasion history and ecology of H. axyridis globally with consideration of future research perspectives. We reflect broadly on the contributions of such research to our understanding of invasion biology while also informing policy and people.
- Published
- 2016
31. Intrinsic prey suitability in specialist and generalist Harmonia ladybirds: a test of the trade-off hypothesis for food specialization
- Author
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Naoya Osawa and Suzuki Noriyuki
- Subjects
Aphid ,biology ,Ecology ,Insect Science ,Coccinellidae ,Harmonia ,biology.organism_classification ,Trade-off ,Generalist and specialist species ,Predator ,Ecology, Evolution, Behavior and Systematics ,Harmonia axyridis ,Predation - Abstract
The trade-off hypothesis posits that increased performance on a given resource comes at the cost of decreased performance on other resources, and that this trade-off is a driving force of food specialization in both predators and herbivores. In this study, we examined larval survival and performance in two sibling ladybird species, Harmonia yedoensis Takizawa and Harmonia axyridis Pallas (Coleoptera: Coccinellidae), fed on one of four prey species. Harmonia yedoensis is a specialist predator that preys mostly on pine aphids in the field, whereas H. axyridis is a generalist predator with a broad prey range. We experimentally showed in the laboratory that larval survival and performance were not higher when H. yedoensis was fed on pine aphids, compared with the other prey species. Rather, prey suitability was similar in both ladybird species, and H. yedoensis larvae developed as well or even better on prey species that they never utilize in nature. These results suggest that the host range in H. yedoensis may not be limited by the intrinsic suitability of the aphid species per se. Moreover, as shown by our previous study, the pine aphid is a highly elusive prey that is difficult for small ladybird hatchlings to capture, which means that the cost of utilizing this prey is high. Therefore, we conclude that some factor other than prey suitability is responsible for the observed food specialization in H. yedoensis.
- Published
- 2012
32. Asymmetric reproductive interference between specialist and generalist predatory ladybirds
- Author
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Suzuki Noriyuki, Takayoshi Nishida, and Naoya Osawa
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biology ,Animal ecology ,Ecology ,Niche differentiation ,Animal Science and Zoology ,Mating ,biology.organism_classification ,Generalist and specialist species ,Sperm precedence ,Predator ,Ecology, Evolution, Behavior and Systematics ,Harmonia axyridis ,Predation - Abstract
1. Closely related species often differ greatly in the quality and breadth of resources exploited, but the actual mechanisms causing these differences are poorly understood. Because in the laboratory specialized species often survive and perform as well or better on host species that are never utilized in nature, negative ecological interactions restricting host range must exist. Here, we focused on reproductive interference, which has been theoretically predicted to drive niche separation between closely related species with overlapping mating signals. 2. We examined the interspecific sexual interactions in relation to ecological specialization and generalization in two sibling ladybird species, Harmonia yedoensis and Harmonia axyridis. Harmonia yedoensis is a specialist predator that preys only on pine aphids, which are highly elusive prey for ladybird hatchlings, whereas H. axyridis is a generalist predator with a broad prey and habitat range. 3. We experimentally showed that conspecific sperm fertilized the vast majority of eggs regardless of mating order (i.e. conspecific sperm precedence) when a female of H. yedoensis or H. axyridis mated with both a conspecific and a heterospecific male. Moreover, we demonstrated that mating opportunities of H. yedoensis females strongly decreased as heterospecific density increased relative to conspecific density. In contrast, in H. axyridis, female mating success was high regardless of conspecific or heterospecific density. 4. Our results suggest that the generalist H. axyridis should be dominant to the specialist H. yedoensis in terms of reproductive interference. Our results support the hypothesis that asymmetric reproductive interference from the dominant species may force the non-dominant species to become a specialist predator that exclusively utilizes less preferred prey in nature.
- Published
- 2012
33. Factors promoting maternal trophic egg provisioning in non‐eusocial animals
- Author
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Naoya Osawa, Kazutaka Kawatsu, and Suzuki Noriyuki
- Subjects
Phenotypic plasticity ,Trophic egg ,Ecology ,Offspring ,embryonic structures ,Interspecific competition ,Biology ,Adaptation ,Parental investment ,Eusociality ,Ecology, Evolution, Behavior and Systematics ,Trophic level - Abstract
The adaptive function of trophic egg-laying is generally regarded as extended parental investment to the offspring. However, the evolutionary factors promoting trophic egg-laying are still unclear, because the amount of maternal investment per offspring should be ideally equal between smaller offspring with trophic eggs and larger offspring without any additional investment. Several authors have suggested that trophic egg-laying should evolve only when egg size is constrained, but this hypothesis has not been evaluated. We investigated the evolutionary mechanisms of trophic egg-laying by two different approaches. First, we evaluated morphological constraints on egg size in two sibling ladybird species, Harmonia axyridis, which is known to produce trophic eggs, and H. yedoensis. Second, we theoretically predicted the optimal proportion of trophic eggs to total eggs and egg size in relation to environmental heterogeneity, predictability of environmental quality, and investment efficiency of trophic egg consumption. The intra- and interspecific morphological comparisons suggest that morphological constraints on the evolutionary determination of egg size are weak at best in the two ladybird species. Moreover, we theoretically showed that small egg size and trophic egg-laying are favoured in heterogeneous environments when mothers cannot adjust egg size plastically. We also showed that even a small reduction in investment efficiency makes a trophic egg strategy unlikely, despite relatively high environmental predictability. We conclude that trophic egg provisioning may be a flexible maternal adaptation to a highly heterogeneous environment rather than a response to a morphological constraint on egg size.
- Published
- 2012
34. Variation in herbivory-induced responses within successively flushing Quercus serrata seedlings under different nutrient conditions
- Author
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Naoya Osawa, Naoko Tokuchi, Eri Mizumachi, Akira Mori, and Reiko Akiyama
- Subjects
0106 biological sciences ,Forest floor ,chemistry.chemical_classification ,Herbivore ,Forestry ,Biology ,Quercus serrata ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Plant ecology ,Horticulture ,Nutrient ,chemistry ,Botany ,Condensed tannin ,Soil fertility ,010606 plant biology & botany ,Woody plant - Abstract
Herbivore damage can induce the host plant to alter the chemical and physical qualities of its leaves, which is thought to be a plant strategy—termed “induced response”—for avoiding further herbivory. In woody plants, many studies have considered variation in induced response with resource availability, but few studies have examined this variation in relation to growth patterns of woody plants. We studied the phenotypic variability of induced response within successively flushing Quercus serrata seedlings. Q. serrata seedlings were grown under controlled conditions. The controlled factors were herbivore damage (herbivore-damaged and -undamaged) and soil fertility (low and high). At each flush stage, the concentrations of condensed tannin (CT), total phenolics (TP), and nitrogen (N) in leaves were analyzed, and the leaf mass per area (LMA) was measured. CT and TP concentrations in leaves and LMA were higher in herbivore-damaged seedlings. Leaves of the first flushes showed greater sensitivity to herbivore damage and had a higher CT concentration than leaves of the later flushes. Furthermore, seedlings growing in low-fertility soil showed a greater induced response. The results suggest that the induced response of Q. serrata seedlings was related to the contributions of the tissue to current productivity. Leaves of the first flush showed a greater induced response, possibly because they play an important role in subsequent growth. The potential of Q. serrata seedlings to adjust the properties of leaves depending on herbivory and soil fertility in relation to growth patterns may be advantageous on the forest floor, where seedlings grow in soil of heterogeneous fertility and are constantly exposed to herbivory.
- Published
- 2012
35. The community structures of fungivorous insects onAmanita muscariain New Zealand
- Author
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Nobuko Tuno, Komei Kadowaki, Naoya Osawa, Peter K. Buchanan, Richard J. Toft, Toshimitsu Fukiharu, and Chihiro Tanaka
- Subjects
Nothofagus ,biology ,Ecology ,Insect Science ,Biodiversity ,Agaricales ,Amanitaceae ,biology.organism_classification ,Endemism ,Mycetophilidae ,Trichoceridae ,Amanita muscaria - Abstract
The toxic ectomycorhizal fungi Amanita muscaria (Agaricales: Amanitaceae) was first recorded in New Zealand in 1937, and it is now widespread throughout the country. We collected decaying fruiting bodies of the mushroom in 2005 and 2006 and placed them in enclosed emergence traps to determine use by fungivorous insects. This study clarified that the endemic species Mycetophila fagi, M. filicornis (Diptera: Mycetophilidae) and Zedura curtisi (Diptera: Trichoceridae), as well as exotic Drosophila busckii (Diptera: Drosophilidae), utilised the exotic A. muscaria in various vegetation types in the North and South Islands of New Zealand. A significant difference was observed in the number of fungivorous insects found on the mushrooms between North and South Islands; the endemic M. fagi was dominant in South Island, while Psychodidae sp. dominated North Island. A significant difference was observed in the number of fungivorous insects between the exotic and endemic vegetation inhabited by A. muscaria. Furthermore, the biodiversity of fungivorous insects on A. muscaria within endemic Nothofagus vegetation was more than three times greater than that within the exotic Betula , Pinus, Pseudotsuga and tsuga vegetation. These observations suggest that the greater diversity of fungivorous insects on A. muscaria in natural Nothofagus forests may reflect the higher diversity found in natural forests compared with plantation forests.
- Published
- 2011
36. Sprout initiation and growth for three years after cutting in an abandoned secondary forest in Kyoto, Japan
- Author
-
Junichi Imanishi, Asami Nakanishi, Shozo Shibata, Shinjiro Sakai, Junko Morimoto, Ayumi Imanishi, and Naoya Osawa
- Subjects
Lyonia ovalifolia ,Ecology ,biology ,Management, Monitoring, Policy and Law ,biology.organism_classification ,Japonica ,Suburban secondary forest ,Plant ecology ,Sprout ability ,Horticulture ,Shoot ,Botany ,cardiovascular system ,Secondary forest ,Eurya japonica ,Vegetation management ,Nature and Landscape Conservation ,Sprouting ,Woody plant - Abstract
Secondary forests in Japan have been abandoned and the ecosystem has degraded since the high economic growth period. We carried out cutting in January in three small areas of a long-abandoned secondary forest and investigated the sprout initiation and growth of woody plants for three years in order to reveal the early stage of sprout regeneration and to understand the sprouting ability and characteristics of each species for effective management. The percentage of sprouted stumps and the number of sprouting shoots was substantially maximized in autumn in the first year. These results suggest that autumn monitoring in the first year after cutting shows the maximum percentage of sprouted stumps and the maximum sprout number when cutting was conducted in the dormant season. With regards to species characteristics, Eurya japonica showed a low percentage of sprouted stumps in the lower plot, where the mean diameter at breast height for this species was smaller than in the other plots. The sprouting ability of E. japonica was deemed to be influenced by parent tree size. Ilex pedunculosa and Lyonia ovalifolia var. elliptica had high percentages of sprouted stumps and many sprouts. These species are useful for obtaining sprouting shoots (e.g., for firewood), but it is difficult to control their sprouting.
- Published
- 2010
37. Generalist pollinators in the dioecious shrubRhus trichocarpaMiq. (Anacardiaceae) and their role in reproductive success
- Author
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Shuhei Matsuyama, Naoya Osawa, and Michinori Sakimoto
- Subjects
Spider ,Ecology ,Pollination ,Reproductive success ,ved/biology ,Dioecy ,ved/biology.organism_classification_rank.species ,Plant Science ,Biology ,Generalist and specialist species ,Eusociality ,Shrub ,Pollinator ,Ecology, Evolution, Behavior and Systematics - Abstract
We examined the floral display size and potential pollinators of female and male Rhus trichocarpa in northern Kyoto, Japan, in June 2005. The entomophilous pollination system comprised 431 insects and one spider belonging to 124 species. Most pollinators were non-social bees and occasional Diptera and Coleoptera, whereas eusocial bees were not dominant in the pollination system. Male-biased frequencies were observed in the eusocial bees and in some of the non-social bees, probably because they are sensitive to the larger male floral rewards. A pollinator introduction experiment confirmed that male-biased, unbiased and infrequent non-social bees can pollinate R. trichocarpa, indicating that non-social bees can contribute to fruit set. The results suggest that there are likely to be two different functional groups of generalist pollinators: (i) the majority of the pollinators may contribute to reproductive success through unbiased and occasional visits; and (ii) a minority group of eusocial bees may contribute to reproductive success through male-biased visits.
- Published
- 2009
38. Effects of patch cutting on leaf nitrogen nutrition in hinoki cypress (Chamaecyparis obtusa Endlicher) at different elevations along a slope in Japan
- Author
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Asami Nakanishi, Naoya Osawa, Kei’ichi Hirata, Shozo Shibata, and Yoshiyuki Inagaki
- Subjects
0106 biological sciences ,biology ,fungi ,food and beverages ,chemistry.chemical_element ,Forestry ,Soil classification ,Mineralization (soil science) ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Nitrogen ,Plant ecology ,Horticulture ,chemistry ,Chamaecyparis ,Botany ,Cycling ,Nitrogen cycle ,Hinoki Cypress ,010606 plant biology & botany - Abstract
Leaf nitrogen nutrition of hinoki cypress (Chamaecyparis obtusa Endlicher) was investigated at three positions along a slope over a period of 3 years. At each slope position, nitrogen properties were compared in patch-cut plots (0.06–0.09 ha) and uncut control plots (0.04 ha). Nitrogen cycling at the lower slope was characterized by a higher rate of soil nitrogen mineralization, and higher nitrogen concentration in fresh leaves and leaf-litter. The soil nitrogen mineralization rate and fresh-leaf nitrogen concentration in the patch-cut plots were higher than those in the control plots. However, leaf-litter nitrogen concentration did not differ between the patch-cut and control plots. The results suggest that slope position strongly affects leaf nitrogen nutrition of hinoki cypress and soil nitrogen availability. By contrast, patch cutting does not affect leaf-litter nitrogen concentration. These findings indicated that hinoki cypress would not enhance forest nitrogen cycling through changes in leaf-litter nitrogen concentration after patch cutting.
- Published
- 2009
39. The presence of micropyles in the shells of developing and undeveloped eggs of the ladybird beetle Harmonia axyridis (Coleoptera: Coccinellidae)
- Author
-
Arata Yoshinaga and Naoya Osawa
- Subjects
biology ,Heteroptera ,Hymenoptera ,biology.organism_classification ,trophic egg ,Harmonia axyridis ,sibling cannibalism ,QL1-991 ,Insect Science ,coccinellidae ,Botany ,embryonic structures ,morphology ,Coccinellidae ,hatchability ,infertile egg ,Zoology ,scanning electron microscopy ,Trophic level ,harmonia axyridis - Abstract
In Hymenoptera and Heteroptera, the absence of micropyles is one criterion for categorizing an egg as trophic. Undevel- oped eggs are observed in more than 90% of the egg clusters of the ladybird beetle Harmonia axyridis Pallas. Traditionally, these undeveloped eggs are regarded as "trophic eggs." The surfaces of the eggs of H. axyridis were examined using scanning electron microscopy and the presence of micropyles in the shells of developing and undeveloped eggs determined. Micropyles are circularly distributed around the top of eggs and present in both developing and undeveloped eggs. The number of micropyles in the shells of developing and undeveloped eggs did not differ significantly. Our results indicate that the undeveloped eggs of H. axyridis have micropyles, suggesting that the mechanisms regulating the production of undeveloped eggs in H. axyridis differ from those resulting in the production of trophic eggs by Hymenoptera and Heteroptera.
- Published
- 2009
40. [Untitled]
- Author
-
Ayumi IMANISHI, Junko MORIMOTO, Shozo SHIBATA, Asami NAKANISHI, and Naoya OSAWA
- Published
- 2009
41. Sympatric coexistence of sibling species Harmonia yedoensis and H. axyridis (Coleoptera: Coccinellidae) and the roles of maternal investment through egg and sibling cannibalism
- Author
-
Kazunori Ohashi and Naoya Osawa
- Subjects
Larva ,harmonia yedoensis ,biology ,Ecology ,Hatching ,coexistence ,Cannibalism ,Zoology ,biology.organism_classification ,Harmonia axyridis ,Predation ,sibling cannibalism ,sibling species ,QL1-991 ,Sympatric speciation ,coccinellidae ,Insect Science ,Instar ,Coccinellidae ,harmonia axyridis - Abstract
The sibling species H. yedoensis Takizawa coexists sympatrically and simultaneously with H. axyridis only on pine trees in Japan. To elucidate the mechanisms enabling coexistence of these two sympatric sibling species, a laboratory experiment was per- formed that focused on differences in their maternal investment through eggs and the role of sibling cannibalism. The egg size (vol- ume) of H. yedoensis was 24.91% larger than that of H. axyridis. Cluster size in H. axyridis was significantly larger than that in H. yedoensis; however, the total number of eggs and oviposition cost (by volume) per female in H. yedoensis were not significantly dif- ferent from those in H. axyridis, although total number of clusters tended to be slightly higher in H. yedoensis than in H. axyridis. The percentage of undeveloped eggs per cluster in H. yedoensis was not significantly different from that in H. axyridis, whereas the percentage of developed eggs with delayed hatching per cluster was significantly larger in H. yedoensis than in H. axyridis. Moreo- ver, the cost of sibling cannibalism per hatched larval cluster in H. yedoensis (worth 4.43 sibling eggs) was 3.36 times larger than that in H. axyridis.Therefore, maternal investment through egg and sibling cannibalism in developed eggs with delayed hatching are more intense in H. yedoensis than in H. axyridis, implying a higher larval survival rate through higher ability of prey capturing at the first instar. The results in this study suggest that the higher survival rate and accelerated development in H. yedoensis by the two maternal investments, i.e., a large egg and intense sibling cannibalism of developed eggs with delayed hatching, may play an impor- tant role in sympatric coexistence with the aggressive aphidophagous ladybird beetle H. axyridis.
- Published
- 2008
42. Change of woody-species composition in an early stage of plant succession after cutting in a suburban secondary forest dominated by Chamaecyparis obtusa
- Author
-
Yukihiro Morimoto, Asami Nakanishi, Ayumi Imanishi, Shozo Shibata, Naoya Osawa, Atsumi Terai, Junichi Imanishi, and Shinjiro Sakai
- Subjects
biology ,Ecology ,Stage (stratigraphy) ,Chamaecyparis ,Secondary forest ,Forestry ,Composition (visual arts) ,Ecological succession ,biology.organism_classification - Abstract
ヒノキ林化した都市近郊二次林をアカマツまたは落葉広葉樹主体の林相に転換させることを目的として,母樹を残した小面積 (0.06~0.09 ha) の伐採を行った。3 つの伐採区 (上部,中部,下部) のいずれにおいても伐採後に消失した種はなく,伐採後3 年目には10 種以上の種数の増加が確認された。中でも,落葉広葉樹林の主要構成要素を含むブナクラスの種が上部と中部では6 種,下部では4 種増加し,林相転換に一定の効果が得られたと考えられた。前生稚樹は伐採後にほとんどの個体が枯死し,伐採後の林相には大きく寄与していなかった。散布種子についてはその大部分がヒノキで占められており,風散布種であるヒノキはプロット内に多量の種子を散布することで伐採後の林相に大きな影響を与えると考えられた。また,伐採後3 年目には新たな種の出現がほとんどみられなかったことから,林相が単純なヒノキ林では周囲からの新たな種の供給は少ないと考えられた。伐採面積の最も大きかった上部の伐採区 (0.09 ha) では,相対日射量が60% 以上あり,ヒノキの発芽と生存率が抑制されたと考えられ,アカマツとヒノキの混交する林相への転換が期待された。一方,中部と下部の伐採区では,全実生個体数のうちヒノキが50% 以上を占めており,今後,選択的除去などの人為的な管理が必要であると考えられた。
- Published
- 2008
43. Tolerance of Drosophila Flies to Ibotenic Acid Poisons in Mushrooms
- Author
-
Naoya Osawa, Kazuo H. Takahashi, Nobuko Tuno, Chihiro Tanaka, and Hiroshi Yamashita
- Subjects
Amanita ,animal structures ,Mushroom Poisoning ,Biochemistry ,chemistry.chemical_compound ,Species Specificity ,Drosophilidae ,Botany ,Melanogaster ,Animals ,Body Size ,Ibotenic Acid ,Drosophila ,Ecology, Evolution, Behavior and Systematics ,Mushroom ,Dose-Response Relationship, Drug ,biology ,Muscimol ,fungi ,Pupa ,General Medicine ,biology.organism_classification ,chemistry ,Larva ,Drosophila melanogaster ,Ibotenic acid - Abstract
The mushroom genus Amanita has a spectrum of chemical compounds affecting survival and performance of animals. Ibotenic acid is one of such compounds found in some Amanita mushrooms. We studied the effects of ibotenic acid and its derivative, muscimol, on egg-to-pupa survival, pupation time, and pupal size in five Drosophila species (Diptera: Drosophilidae), Drosophila bizonata, Drosophila angularis, Drosophila brachynephros, Drosophila immigrans, and Drosophila melanogaster. The first three species are mycophagous and use a wide range of mushrooms for breeding, whereas D. immigrans and D. melanogaster are frugivorous. We reared fly larvae on artificial medium with 500, 250, 125, and 62.5 microg/ml of ibotenic acid and/or musimol. The three mycophagous species were not susceptible to ibotenic acid, whereas the two frugivorous species were affected. In experiments with D. melanogaster, muscimol was less toxic than ibotenic acid.
- Published
- 2006
44. Shoot Development and Extension of Quercus serrata Saplings in Response to Insect Damage and Nutrient Conditions
- Author
-
Naoya Osawa, Naoko Tokuchi, Akira Mori, Eri Mizumachi, and Reiko Akiyama
- Subjects
Insecta ,Nitrogen ,Growing season ,Plant Science ,Quercus serrata ,Phosphorus metabolism ,Quercus ,Soil ,Nutrient ,Botany ,Animals ,Compensatory growth (organism) ,Nitrogen cycle ,Herbivore ,biology ,fungi ,food and beverages ,Phosphorus ,Original Articles ,biology.organism_classification ,digestive system diseases ,Plant Leaves ,Horticulture ,Shoot ,Potassium ,Regression Analysis ,Plant Shoots - Abstract
• Background and Aims Plants have the ability to compensate for damage caused by herbivores. This is important to plant growth, because a plant cannot always avoid damage, even if it has developed defence mechanisms against herbivores. In previous work, we elucidated the herbivory-induced compensatory response of Quercus (at both the individual shoot and whole sapling levels) in both low- and high-nutrient conditions throughout one growing season. In this study, we determine how the compensatory growth of Quercus serrata saplings is achieved at different nutrient levels. • Methods Quercus serrata saplings were grown under controlled conditions. Length, number of leaves and percentage of leaf area lost on all extension units (EUs) were measured. • Key Results Both the probability of flushing and the length of subsequent EUs significantly increased with an increase in the length of the parent EU. The probability of flushing increased with an increase in leaf damage of the parent EU, but the length of subsequent EUs decreased. This indicates that EU growth is fundamentally regulated at the individual EU level. The probabilities of a second and third flush were significantly higher in plants in high-nutrient soil than those in low-nutrient soil. The subsequent EUs of damaged saplings were also significantly longer at high-nutrient conditions. • Conclusions An increase in the probability of flushes in response to herbivore damage is important for damaged saplings to produce new EUs; further, shortening the length of EUs helps to effectively reproduce foliage lost by herbivory. The probability of flushing also varied according to soil nutrient levels, suggesting that the compensatory growth of individual EUs in response to local damage levels is affected by the nutrients available to the whole sapling.
- Published
- 2006
45. Thrips (Thysanoptera: Thripidae) on the flowers of a dioecious plant,Dioscorea japonica(Dioscoreaceae)
- Author
-
Inoue Mizuki, Naoya Osawa, and Tadaaki Tsutsumi
- Subjects
Dioscorea japonica ,biology ,Thrips ,Pollination ,Physiology ,Dioscoreaceae ,Fauna ,Thripidae ,biology.organism_classification ,Japonica ,Structural Biology ,Genus ,Insect Science ,Botany ,Molecular Biology ,Ecology, Evolution, Behavior and Systematics - Abstract
The genusDioscoreaL. (Dioscoreaceae) is widely distributed throughout Africa and Asia and includes 500 to 650 species (Burkill 1960; Miège and Lyonga 1982), almost all of which are dioecious (Terauchi 1990). Pollination of species in this genus has received little attention because many of the cultivated species are propagated vegetatively from tubers. Insect visitors to flowers have been reported for two species,D. alataL. from India (Abraham and Nair 1990) andD. rotundataPoir. from Nigeria (Pitkin 1973; Segnouet al.1992; Bournier 1994).Dioscorea japonicaThunb. is found throughout Japan, Korea, and China (Ohwi and Kitagawa 1983), but insect visitors to the flowers have not previously been reported. We investigated the insect visitors to flowers ofD. japonicabecause the insect fauna associated with one species of a genus often differs from that associated with other species of the genus and may vary within a single species between different geographic regions (Kobayashiet al.1999).
- Published
- 2005
46. Logging impacts on forest carabid assemblages in Japan
- Author
-
Naoya Osawa, Atsumi Terai, Kei’ichi Hirata, Shozo Sibata, Shinjiro Sakai, Ayumi Makino, and Asami Nakanishi
- Subjects
Global and Planetary Change ,Ecology ,Habitat ,Forest management ,Logging ,Biodiversity ,Temperate climate ,Community structure ,Environmental science ,Forestry ,Ecosystem ,Terrestrial ecosystem - Abstract
We hypothesized that small-area logging (
- Published
- 2005
47. Thermal Microhabitat Use by the Ladybird Beetle,Coccinella septempunctata(Coleoptera: Coccinellidae), and Its Life Cycle Consequences
- Author
-
Kazunori Ohashi, Naoya Osawa, Shuichi Yano, Yasuyuki Sakuratani, and Akio Takafuji
- Subjects
Ecology ,biology ,biology.organism_classification ,Egg laying ,Coccinella septempunctata ,Predation ,Pupa ,Habitat ,Insect Science ,Coccinellidae ,Life history ,Ecology, Evolution, Behavior and Systematics ,Overwintering - Abstract
Most central Honshu populations of the ladybird beetle, Coccinella septempunctata L., pass the winter as quiescent adults. However, variations in life cycle within populations have been observed: hibernating and reproductive adults simultaneously coexist in the same habitat in winter. We studied microhabitat use patterns of this beetle in winter on a sunny slope of a southeast-facing riverbank. We found that, even though natural substrates were available, the beetle preferred to use artificial substrates such as metal cans (iron or aluminum), papers, and wooden materials discarded on the slope as oviposition and pupation sites. The artificial substrates were relatively easily warmed by solar radiation and were therefore used as thermal microhabitats by the beetle. Although ambient winter air temperatures of this region were not high enough for the beetles to complete their development, the use of thermal microhabitats enabled them to do so by thermal conduction. Prey aphids were also abundant during the winter. Thermal microhabitat use enables these beetles to complete an additional generation in winter.
- Published
- 2005
48. Behavior of four broad-leaved tree species used to revegetate eroded granite hill slopes
- Author
-
Hiroshi Takeda, Koji Kawamura, Naoko Tokuchi, Kanae Ishimaru, and Naoya Osawa
- Subjects
Pioneer species ,biology ,fungi ,Crown (botany) ,Forestry ,04 agricultural and veterinary sciences ,010501 environmental sciences ,biology.organism_classification ,01 natural sciences ,Quercus glauca ,Broad-leaved tree ,Agronomy ,Botany ,Relative growth rate ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Allometry ,Growth rate ,Myrica rubra ,0105 earth and related environmental sciences - Abstract
Information on primary growth behavior after planting is required for mixed-plantation revegetation using broad-leaved species. To estimate primary growth, especially from the perspective of crown coverage and changing growth rates, we examined the growth and survival of four broad-leaved species that are frequently used in erosion-control plantations in Japan. The species studied were Myrica rubra Sieb. et Zucc., Alnus pendula Matsum., Quercus glauca Thunb., and Q. serrata Thunb. The survival, height, and basal diameter of planted trees were measured over a 4-year period, and crown area was calculated over a 3-year period. We found a negative relationship between relative growth rate (RGR) and survival rate, suggesting that fast growth may be fatal when resources are severely limited. The relative height growth rate (RHGR) of A. pendula was especially high during the early period of the study (1997–1999) and then drastically declined, whereas the opposite tendency was observed in Q. glauca. The results of stem allometry analyses conformed to the specific relationships between height growth and diameter growth of the four species; increases in stem thickness based on height increments were smaller in the pioneer species A. pendula. Between-species differences in coverage per planted tree (mean crown area multiplied by survival rate) were small as a result of the negative relationship between coverage area and survival rate.
- Published
- 2005
49. Seed bank and seed rain of woody species in a Chamaecyparis obtusar dominated suburban secondary forest
- Author
-
Yuhei Abe, Naoya Osawa, Shozo Shibata, and Asami Nakanishi
- Subjects
Geography ,biology ,Agroforestry ,Chamaecyparis ,Secondary forest ,Forestry ,biology.organism_classification - Abstract
ヒノキ林化した都市近郊二次林において,植生を転換する際に重要となる埋土種子集団の潜在性を把握するために,埋土種子とそれに影響を与える散布種子について調査を行った。調査の結果,ヒノキ林化した二次林の埋土種子集団には,アカマツと落葉広葉樹を主とする植生を形成する潜在性のあることが明らかとなり,鳥類による種子供給は,止まり木としての機能の高い樹木が存在しないところでは少ないと考えられた。現在のところ,埋土種子集団にヒノキが鬱閉する以前の植生を復元する潜在性はあるが,今後もヒノキの鬱閉した状態が継続し,ヒノキの下で止まり木となるような樹木が枯死するようなことになれば,鳥類による種子供給が減少することを通じて,埋土種子集団の組成が変化し,潜在性が低下する可能性のあることが示唆された。
- Published
- 2005
50. The effects of herbivory and soil fertility on the growth patterns of Quercus serrata and Q. crispula saplings at the shoot and individual levels
- Author
-
Naoko Tokuchi, Eri Mizumachi, Reiko Akiyama, and Naoya Osawa
- Subjects
Horticulture ,Herbivore ,Human fertilization ,Botany ,Shoot ,Biology ,Soil fertility ,Individual level ,Quercus serrata ,biology.organism_classification ,digestive system diseases ,Ecology, Evolution, Behavior and Systematics - Abstract
We investigated the combined effects of herbivore damage and soil fertility on shoot growth patterns of Quercus serrata and Q. crispula saplings at both the shoot and individual levels. Saplings were grown in herbivore-damaged or undamaged areas of the greenhouse with the two fertilization treatment levels, low or high. We measured the leaf area loss, number of flushes, length of extension units (EUs; the first vs the higher), number of leaves on each individual, and number of EUs. At the shoot level, the leaf area loss at high soil fertility was significantly greater than that at low soil fertility among the highest EUs of Q. serrata, while this difference was not significant in Q. crispula, suggesting that effect of soil fertility on leaf area loss is species-specific. Furthermore, herbivore damage was associated with a significant increase in the number of EUs and a reduction in the length of the higher EUs under both soil fertility treatments, although saplings had a tendency to produce significantly more flushes and longer individual EUs under the high soil fertility. At the individual level, herbivore-damaged saplings exhibited a significant increase in leaf numbers; however, the total length of the EUs in Q. serrata or Q. crispula was not significantly affected by herbivore damage, regardless of soil fertility. These results suggest that Q. serrata and Q. crispula saplings produce shorter EUs in response to herbivore damage in order to reduce the cost of mechanical support and spread the risk for any subsequent herbivore damage.
- Published
- 2004
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