Search

The exposure to arsenic and mercury in various insect trophic guilds from two mercury mining sites in Mexico was assessed. The two study sites were La Laja (LL) and La Soledad (LS) mines. Additionally, a reference site (LSR) was evaluated for LS. The terrestrial ecosystem was studied at LL, whereas both the terrestrial ecosystem and a stream called El Cedral (EC) were assessed at LS. The study sites are situated in the Biosphere Reserve Sierra Gorda (BRSG). Mercury vapor concentrations were measured with a portable analyzer, and concentrations of arsenic and mercury in environmental and biological samples were determined through atomic absorption spectrophotometry. Both pollutants were detected in all terrestrial ecosystem components (soil, air, leaves, flowers, and insects) from the two mines. The insect trophic guilds exposed included pollinivores, rhizophages, predators, coprophages, and necrophages. In LS, insects accumulated arsenic at levels 29 to 80 times higher than those found in specimens from LSR, and 10 to 46 times higher than those from LL. Similarly, mercury exposure in LS was 13 to 62 times higher than LSR, and 15 to 54 times higher than in LL. The analysis of insect exposure routes indicated potential exposure through air, soil, leaves, flowers, animal prey, carrion, and excrement. Water and sediment from EC exhibited high levels of arsenic and mercury compared to reference values, and predatory aquatic insects were exposed to both pollutants. In conclusion, insects from mercury mining sites in the BRSG are at risk. [ABSTRACT FROM AUTHOR]

Plants and herbivorous insects as well as their natural enemies, such as predatory and parasitoid insects, are united by intricate relationships. During the long period of co-evolution with insects, plants developed a wide diversity of features to defence against herbivores and to attract pollinators and herbivores' natural enemies. The chemical basis of insect-plant interactions is established and many examples are studied, where feeding and oviposition site selection of phytophagous insects are dependent on the plant's secondary chemistry. However, often overlooked mechanical interactions between insects and plants can be rather crucial. In the context of mechanoecology, the evolution of plant surfaces and insect adhesive pads is an interesting example of competition between insect attachment systems and plant anti-attachment surfaces. The present review is focused on mechanical insect-plant interactions of some important pest species, such as the polyphagous Southern Green Stinkbug Nezara viridula and two frugivorous pest species, the polyphagous Mediterranean fruit fly Ceratitis capitata and the monophagous olive fruit fly Bactrocera oleae. Their ability to attach to plant surfaces characterised by different features such as waxes and trichomes is discussed. Some attention is paid also to Coccinellidae, whose interaction with plant leaf surfaces is substantial across all developmental stages in both phytophagous and predatory species that feed on herbivorous insects. Finally, the role of different kinds of anti-adhesive nanomaterials is discussed. They can reduce the attachment ability of insect pests to natural and artificial surfaces, potentially representing environmental friendly alternative methods to reduce insect pest impact in agriculture. [ABSTRACT FROM AUTHOR]

The global use of pesticides, exceeding 4 million tons annually, poses substantial threats to public health and the environment. Numerous studies emphasize the correlation between pesticide exposure, genotoxicity, and neurobehavioral effects, which particularly impact children and agricultural workers. Recent research underscores the health risks associated with moderately toxic pesticides like chlorpyrifos. Chlorpyrifos contamination in crops, a result of extensive pesticide use since the 1960s, raises significant concerns regarding human health and the environment. Given its potential atmospheric volatilization from crops, alternative detection methods are imperative. This study employs gas chromatography coupled with mass spectrometry (GC/MS) in MS/MS mode, focusing on detecting chlorpyrifos in Chilean lettuce, using insects as indicators. Two extraction methods, micro-QuEChERS and HEADSPACE-SPME, were compared, with HEADSPACE-SPME demonstrating superior sensitivity (6.77 ng/mg per sample vs. 3.99 ng/mg per sample) and offering time- and solvent-saving advantages. Additionally, HEADSPACE-SPME preserves samples for future research, enhancing its utility. The study confirms the presence of pesticide residues in insects from lettuce crops, with 52.3% displaying chlorpyrifos when the SPME method was used. Predatory and parasitoid insect families like Braconidae and Ichneumonidae show high pesticide loads. The findings of this study emphasize the widespread contamination of chlorpyrifos in lettuce crop insects and highlight the efficacy of SPME for detection, suggesting its broader applicability for evaluating pesticide residues in horticultural systems. This optimized method holds promise for advancing chlorpyrifos contamination detection in agroecosystems, contributing to environmental monitoring and food security. [ABSTRACT FROM AUTHOR]

Abiotic factors strongly influence ecological interactions and the spatial distribution of organisms. Despite the essential role of barometric pressure, its influence on insect behaviour remains poorly understood, particularly in predators. The effect of barometric pressure variation can significantly impact biological control programs involving entomophagous insects, as they must efficiently allocate time and energy to search for prey in challenging environments. We investigated how predatory insects from different taxonomic groups (Coleoptera, Dermaptera and Neuroptera) adapt their foraging behaviour in response to variations in barometric pressure (low, medium and high). We also examined the response of different life stages to changes in pressure regimes during foraging activities. Our results showed that the searching time of Doru luteipes (Dermaptera: Forficulidae) was faster in a favourable high‐pressure regime, whereas Chrysoperla externa (Neuroptera: Chrysopidae) and Eriopis connexa (Coleoptera: Coccinellidae) had similar searching times under varying pressure regimes. Although no differences in prey feeding time were observed among the studied species, the consumption rate was influenced by low barometric pressure leading to a decrease in the number of preyed eggs. Moreover, we provide novel insights into how hemimetabolous (D. luteipes) and holometabolous (E. connexa) species at different life stages respond to barometric pressure. Doru luteipes nymphs and adults had similar consumption rates across all pressure regimes tested, whereas E. connexa larvae consumed fewer eggs under low barometric pressure, but adults were unaffected. This highlights the importance of investigating how abiotic factors affect insects foraging efficiency and predator–prey interactions. Such studies are especially relevant in the current context of climate change, as even subtle changes in abiotic factors can have strong effects on insect behaviour. Barometric pressure is a key meteorological variable that serve as a warning signal for insects to seek shelter and avoid exposure to weather events that could potentially increase their mortality. Understanding the effects of barometric pressure on predatory insects' behaviour can help us develop more effective pest management strategies and promote the resilience of agroecosystems. We provide new insights into the complex relationship between barometric pressure and predator–prey interactions. [ABSTRACT FROM AUTHOR]

Simple Summary: When weeds are left in mango farms, especially native wildflowers, there is a potential they may provide pollen and nectar to increase beneficial insect abundance and diversity. We examined how weed presence affects insects on mango trees as well as soil health. We found that weeds significantly increased pollinating and parasitoid (natural pest control agents) insect abundance and diversity. There was no difference in predatory insects between treatments, and slightly more herbivorous insects on weedy mango trees. Pollinators in mango flowers and spiders were also greater on weedy mango trees. Soil conditions were significantly improved in soil carbon and pH by the presence of weeds. These results show that a tolerable level of weed species may benefit insect, plant, and soil biodiversity in farms which oftentimes have very little life on them. This study examined if weeds could serve as insectary plants to increase beneficial insect abundance and diversity in mango cultivation in southern Florida. Additionally, we examined how weed presence affects mango tree soil health. We found that weeds significantly increased pollinating and parasitoid insect abundance and diversity. Eight insect orders and eighteen families were significantly more abundant on mango trees with weeds growing beneath them than those where weeds were removed. There was no difference in predatory insects between treatments, and slightly more herbivorous insects on weedy mango trees. Pollinating insects visiting mango flowers in the weed treatment were significantly greater, as well as spiders on weedy mango trees. However, there were more lacewings (Neuroptera) observed on the mango trees without weeds, and leaf chlorophyll in the old and new mango leaves was significantly greater, in the weed-free treatment. Soil conditions, however, significantly improved in soil carbon and a greater pH reduction in the presence of weeds, though weeds affected neither soil nitrogen, phosphorous, nor chlorophyll in productive green leaves. These results show that a tolerable level of selective weed species' presence may benefit insect, plant, and soil biodiversity in farms. This is important in increasing production, sustainability, and biodiversity in agriculture, which otherwise may be deficient in non-crop life. [ABSTRACT FROM AUTHOR]

Semiaquatic bugs (Hemiptera: Heteroptera: Gerromorpha) are predatory insects that occupy a wide range of freshwater and marine habitats, with some secondary transitions to terrestrial life. They currently represent more than 2100 species distributed through all continents, except for Antarctica, and are especially rich in the Neotropical and Oriental regions. Although the fauna from the former region is relatively well known, some areas remain almost unexplored. Such is the case of French Guiana, where only a few species have been previously recorded, several of which based on collections made in the 19th and early 20th centuries. As a result of material recently collected in the territory, the descriptions of Rhagovelia depressa Rodrigues, Khila & Moreira, sp. nov., R. tantilloides Rodrigues, Khila & Moreira, sp. nov. and Steinovelia vittata Rodrigues, Khila & Moreira, sp. nov. (Veliidae) are presented here. New records for 28 species are also provided, of which Cylindrostethus hungerfordi Drake & Harris, 1934, Neogerris magnus (Kuitert, 1942), Rheumatobates mangrovensis (China, 1943), R. trinitatis (China, 1943), Ovatametra obesa Kenaga, 1942, Telmatometra fusca Kenaga, 1941, T. parva Kenaga, 1941 (Gerridae), Mesovelia amoena Uhler, 1894 (Mesoveliidae), Rhagovelia brunae Magalhães & Moreira, 2016, R. elegans Uhler, 1894, R. ephydros (Drake & Van Doesburg, 1966), R. equatoria D. Polhemus, 1997, R. evidis Bacon, 1948, R. guianana D. Polhemus, 1997, R. tenuipes Champion, 1898, Oiovelia cunucunumana (Drake & Maldonado-Capriles, 1952), Stridulivelia alia (Drake, 1957), S. stridulata (Hungerford, 1929), and S. tersa (Drake & Harris, 1941) (Veliidae) are reported from French Guiana for the first time. [ABSTRACT FROM AUTHOR]

Plants with glandular trichomes have been shown to attract specialist, mutualistic predatory insects. Despite recent advances in understanding the plant component in this association, few sticky plant specialist insects are well documented and their adaptations to the sticky plant environment are understudied. We here describe and illustrate, for the first time, aspects of the natural history and morphology of a small clade of predatory hemipteran insects, the Bactrodinae (Reduviidae). Our study suggests that these insects are exclusively associated with plant species with glandular trichomes. The relationship is not specific as one species of Bactrodes Stål may be associated with multiple species, genera or even families of plants. We document a unique clamp-like structure formed by one of the pretarsal claws and opposing tarsal spine-like setae that enables Bactrodinae to grasp trichomes and walk on leaves densely covered with trichomes. We further present observations of Bactrodes species scavenging on insects entrapped on leaves. Bactrodinae also oviposit on their host plants, and females engage in behaviours that we interpret as maternal egg guarding, a life history strategy that is rare in predatory true bugs. We speculate that instead of or in addition to decreasing egg predation or egg parasitism, female egg guarding may be a response to the limited availability of sticky plants and a strategy against cannibalism. [ABSTRACT FROM AUTHOR]

Precocious breeding is a major challenge in the culturing of Coptodon rendalli. Laboratory experiments were undertaken to evaluate the biological control potential of two predatory aquatic insects, Anisops debilis and Gerris swakopensis against tilapia fry. The functional response of these insects was determined at different prey densities during a 24 hr experiment. A. debilis and G. swakopensis exhibited type III and type II functional responses, respectively. The attack rate (2.2046) was higher in A. debilis than G. swakopensis (0.00239). Handling time was lower in A. debilis (0.5420) than G. swakopensis (1.6153). Another experiment was done at different prey densities under light and dark conditions. Anisops debilis exhibited a type II functional response under light conditions and a type III functional response under dark conditions. The attack rate of A. debilis declined from 2.5950 under light conditions to 1.2372 under dark conditions. The handling time for A. debilis was lower under dark conditions than under light conditions. G. swakopensis maintained a type II functional response under light and dark conditions. The attack rate for G. swakopensis increased under dark conditions while the handling time declined. The relative control potential (RCP) was also calculated. The RCPs for the 24 hrs experiment, light and dark conditions were 4.7941, 5.4431 and 3.5622, respectively. This probably indicates that A. debilis may be effective in controlling tilapia fry. [ABSTRACT FROM AUTHOR]

Aim: Arthropods as vertebrate predators is a generally overlooked aspect in ecology due to the cryptic nature of these events, the relatively small size of arthropods and the difficulty in finding published data. This study represents the largest global assessment of arthropods preying on vertebrates to provide a conceptual framework, identify global patterns and provide a searchable database. Location: Global. Time period: Present. Major taxa studied: Arthropods and vertebrates. Methods: A systematic literature review was conducted. Results: Over 1,300 recorded observations were collated from 89 countries. Arthropod predators were from 6 classes and 83 families. Vertebrate prey were from 5 classes and 163 families. Spiders represented over half of all predatory events and were the main predator for all vertebrates except birds, which were mostly preyed upon by praying mantises. Forty percent of all prey were amphibians, specifically frogs. Depredated reptiles were nearly all lizards, half of mammal prey were bats, nearly a third of fish were Cypriniformes and half of bird prey were passerines. Predation by spiders was mainly documented from the U.S., Brazil and Australia, and biased mostly everywhere except the U.S.; insect predatory events were mainly documented from Europe, Australia and the Americas, and biased toward North America; amphibian events were mainly from the Americas and strongly biased everywhere, except for the U.S. and Australia; reptiles events were recorded mostly from the Americas and Australia, and biased towards the U.S. and Australia; predation on birds were mainly from the Americas, Australia and Europe, and biased towards Central America and Europe; and mammal events were mostly reported from North and Central America, Australia, and Asia, and strongly biased everywhere except Brazil. Main conclusions: This study demonstrates that arthropods are underestimated predators of vertebrates. Recognizing and quantifying these predator–prey interactions is vital for identifying patterns and the potential impact of these relationships on shaping vertebrate populations and communities. [ABSTRACT FROM AUTHOR]

The polyhedral inclusion bodies (PIBs) of Spodoptera littoralis nucleopolyhedrosis virus (SlNPV) were extracted from droppings of both the house sparrow Passer domesticus Raf. and the cattle egret Bubulcus ibis Bon. Due to the wide host range of the SlNPV, the extracted PIBs were bioassayed versus newly hatched larvae (L1) of S. littoralis, S. exigua, Trichoplusia ni, and Autographa circumflexa belonging to the insect fauna of the Egyptian clover Trifolium alexandrinum L. and the greater wax moth Galleria mellonella. Mortality of treated neonates of the 5 tested insect species ranged between 80 and 100 % after 7 days from ingesting the PIB-contaminated diet. Feeding nymphs and adults of the earwig Labidura riparia Pallas on S. littoralis larvae infected with the nuclear polyhedrosis virus (SlNPV) passed viable PIBs in feces which were extracted and bioassayed versus lepidopteran larvae of L1. All of the virus-treated 5 lepidopteran species became infected with the virus and showed mortality of 44–96% at the 7th day post ingestion of the extracted PIBs. On the other hand, feces extract of the 3rd larval instar (L3) of the lacewing Parachrysopa pallens (R.) fed on the virus-diseased larvae of S. littoralis caused no mortality when assayed versus the 5 tested lepidopteran larvae proving absence of viable PIB polyhedra that might be due to the mode of larval feeding by external digestion of its host contents including the polyhedra. Results explain the potential role played by insectivorous birds in spreading the nucleopolyhedrosis viruses in the agroecosystem as well as certain predatory insects. [ABSTRACT FROM AUTHOR]

Field studies were conducted on cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Sternorrhyncha: Coccoidea: Pseudococcidae) which infested green bean plants at Atfih distract, Giza Governorate, Egypt during two successive summer and nili seasons of 2016 and 2017. The population density, activity periods and the effects of some weather factors on P. solenopsis and its associated natural enemies were considered. The obtained results revealed that in summer season the total numbers of alive stages had one peak of activity in the 3rd of July during the first and second seasons (2016 and 2017), successively. While, in nili season the total number of alive stages had one peak of activity in the 3rd and the 17th December, during the first and second seasons (2016 and 2017), respectively. The total effects of some weather factors such as maximum and minimum air temperature (°C) and relative humidity percentage (RH%) showed significantly positive relationship with the cotton mealybug population. During this study, three hymenopterous solitary endparasitoids and four predacious species were recorded. The parasitoids were Aenasius arizonensis (Girault), Anagyrus pseudococci (Girault) and Acerophagus gutierreziae Timberlake (Encyrtidae). The predacious ones were Scymnus syriacus Mars., Coccinella undecimpunctata (L.) (Coleoptera: Coccinellidae), Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Orius laevigatus (Fiber.) (Hemiptera: Anthocoridae). In an attempt to control this insect pest specie, eight insecticides namely, mineral oil, lufenuron, chlorpyrifos, malathion, deltamethrin, buprofezin, thiamethoxam and imidacloprid were tested on P. solenopsis and its natural enemies on green bean under field conditions. The obtained results indicated that imidacloprid was the highest efficacy against P. solenopsis recording 90.71-89.17% reduction of the insect population after 21 days of application. Also imidacloprid was the highest efficacy against parasitoids and predators of the cotton mealybug. IGRs toxicants (buprofezin and lufenuron) found to be safer to the predacious insects than other tested insecticides. [ABSTRACT FROM AUTHOR]

Invertebrate assemblages of tropical freshwater rock pools (FRPs) are poorly known compared with temperate regions, where FRPs contain specialized, endemic taxa of high conservation value. Invertebrates were sampled from pristine FRPs in the Morgan River catchment in the Australian wet–dry tropics in the 2015 and 2016 wet seasons. Taxa were classified as either active or passive dispersers and by functional feeding groups. A range of physical variables were examined to identify associations with invertebrate assemblages.Forty‐seven taxa were identified from FRPs; most were actively dispersing predatory insects, primarily Coleoptera and Hemiptera. Five adult insect species were found in most pools; other taxa were rare and scattered across FRPs. Two previously undescribed species of Spinicaudata were collected, but few crustacean taxa were recorded, and passively dispersing taxa were rare. Species accumulation curves indicated that had more pools been sampled, more taxa would have been collected in 2015, but in 2016 most species were collected.There was no pattern in FRP assemblages related to any physical variable, but the assemblages in pools were correlated between sampling times. An opportunistic and mobile assemblage composed mostly of actively dispersing predatory insects may explain the absence of relationships with measured variables. Low hydrological stability in the wet–dry tropics may be associated with low taxon richness.The dominance of actively dispersing insects is in contrast with FRP assemblages in temperate and arid regions. Studies of a wider range of FRPs from tropical regions are required to determine whether the fauna of these Kimberley FRPs are typical, and to fully describe short‐range endemic species across the Kimberley and elsewhere.The FRPs have conservation value as habitat for endemic, specialist rock‐pool taxa, contributing to regional species pools. At present, a lack of knowledge of endemic FRP specialist species in tropical regions, including the Kimberley, impedes our ability to protect and conserve these species from disturbance. [ABSTRACT FROM AUTHOR]

Praying mantids are predators that consume a wide variety of insects. While the gut microbiome of carnivorous mammals is distinct from that of omnivores and herbivores, the role of the gut microbiome among predatory insects is relatively understudied. Praying mantids are the closest known relatives to termites and cockroaches, which are known for their diverse gut microbiota. However, little is known about the mantid gut microbiota or their importance to host health. In this work, we report the results of a 16S rRNA gene-based study of gut microbiome composition in adults and late-instar larvae of three mantid species. We found that the praying mantis gut microbiome exhibits substantial variation in bacterial diversity and community composition. The hindgut of praying mantids were often dominated by microbes that are present in low abundance or not found in the guts of their insect prey. Future studies will explore the role of these microbes in the digestion of the dietary substrates and/or the degradation of toxins produced by their insect prey. [ABSTRACT FROM AUTHOR]

Characterization of intraspecific variation is required to assess the potential nontarget effects of augmentative releases of Hippodamia convergens (Guerin) (Coleoptera: Coccinellidae) from the Western United States on local populations of this species in the Eastern United States. Adults of this predatory lady beetle species overwinter in adult reproductive diapause, thus examining responses to photoperiods can characterize geographic variation influencing their seasonal biology. This laboratory study quantified the induction and duration of adult reproductive diapause in five North American populations of H. convergens in response to four constant photoperiods (16:8, 14:10, 12:12, and 10:14 [L:D] h) at 22°C. Three populations were collected over a range of latitudes (31° N to 42° N) in the central portion of the United States (Texas, Kansas, and Iowa); two populations were purchased from commercial sources in the Western United States. All populations exhibited a long-day response to photoperiods: ≤17% of females reared at 16:8 (L:D) h entered diapause, whereas shorter photoperiods (12:12 and 10:14 [L:D] h) induced diapause in 82 to 100% of females. The response to 14:10 (L:D) h showed significant variation among the populations, ranging from 0 to 89% of females in reproductive diapause. Both the phenotypic variation in response to diapause inducing photoperiods and the genetic variation in North American populations of H. convergens document the geographic variability in this widely distributed predatory species. [ABSTRACT FROM AUTHOR]

Inter-specific relationships of size and walking speed were examined in five species of predaceous ladybird beetles of aphid prey from different habitats. Lengths of legs, weight and volume of body, and walking speed varied significantly among the five species of different sizes that were reared on their preferred prey food in uniform growth conditions. The species are Menochilus sexmaculata, Coccinella transversalis, Anisolemnia dilatata, Micraspis discolor and Scymnus sp. Lengths of legs and body sizes showed similar growth rates across the five species (isometry), but the giant ladybird species showed significantly higher positive allometry in body volume (allometric coefficient, α = 6.66) and significantly lower negative allometry in walking speed relative to body weight (α = 0.95) when compared to other species (α = 3.54). The unique response by the giant ladybird species in body form and speed may be attributed to its foraging habitat of perennial bamboo forests with large aggregations of non-winged aphid food which seem to favour the evolution of higher body volume and slower speed for giant size when compared to species of smaller sizes which usually forage for short-lived aphid colonies in seasonal and annual habitats of crop plants and weeds. Evidently, size (weight and volume) and speed matter in the evolution of life history attributes of predaceous ladybird beetles. [ABSTRACT FROM AUTHOR]

Urban gardens can harbour a high diversity of insects, which are critically important components of urban ecosystems. In this work, we investigate the richness and diversity of a major taxon of economic and ecological importance, the aphids (Hemiptera: Aphididae), and their main insect predators, the hoverflies (Diptera: Syrphidae) and ladybirds (Coleoptera: Coccinellidae), in urban gardens. We examined how variation in environmental factors associated with urbanisation (garden host plant abundance, garden plant richness, garden size, proportion of impervious surfaces in the surrounding area) directly and indirectly (via prey and predator abundance) influence the local diversity and abundance of aphids, ladybirds, and hoverfl ies. Sixty-seven domestic gardens located in southern England were surveyed during the peak period of aphid abundance, and the numbers and identity of aphids and their predators were recorded. We observed 45 aphid species (179917 individuals in total), 15 hoverfl y species (494 individuals) and 8 ladybird species (173 individuals). We found that aphid species richness and abundance were positively associated with utilised host plant abundance and garden plant species richness. Hoverfl y abundance was positively correlated with garden plant richness. The abundance of ladybirds was positively correlated with aphid abundance and garden plant species richness, and negatively associated to the proportion of impervious surfaces in the surrounding environment. The difference in responses between the two major taxa of aphid predators may refl ect differences in their behaviour and natural history. Our results indicate that overall increases in urban land cover are not favourable for ladybirds as a group, and that fi ne scale habitat variables that are determined by garden owners have the potential to greatly affect the diversity of aphids and their primary predators. [ABSTRACT FROM AUTHOR]

Dastarcus helophoroides Fairmaire (Coleoptera: Bothrideridae) is an effective predatory beetle of larvae and pupae of several cerambycid beetles including Monochamus alternatus and Anoplophora glabripennis. Electroantennography (EAG) and a dynamic two-choice olfactometer were respectively used to measure the antennal and behavioral responses of both sexes to selected volatile compounds. Female and male D. helophoroides exhibited similar EAG and behavioral responses. Significant dose-dependent EAG responses in both sexes were elicited by nonanal, octanal, cis-3-hexenol, 3-carene, (R)-(+)-α-pinene, (S)-(-)-α-pinene, (R)-(+)-limonene and (S)-(-)-limonene. Female and male beetles were repelled at high concentration by cis-3-hexenol and (S)-(-)-limonene, respectively. Both sexes of D. helophoroides were significantly attracted to nonanal, cis-3-hexenol, 3-carene and (R)-(+)-limonene even at low concentrations. These compounds might be used either individually or in mixtures for developing biological control methods to attract this predatory beetle into forest stands threatened by cerambycid beetles. [ABSTRACT FROM AUTHOR]

There are many events in the lives of insects where rapid, effective stress reactions are needed, including fighting conspecifics to defend territories, evading predators, and responding to wounds. A key element of the stress reaction is elevation of heartrate (HR), for enhancing distribution of blood (hemolymph) to body compartments. We conducted two experiments designed to improve understanding of the insect stress reaction and how it is influenced by parasitism in a common beetle species (Odontotaenius disjunctus). By non-destructively observing heartbeat frequency before, during and after applying a stressor (physical restraint) for 10 min, we sought to determine: (1) the exact timing of the cardiac stress reaction; (2) the magnitude of heartrate elevation during stress; and (3) if the physiological response is affected by a naturally-occurring nematode parasite, Chondronema passali. Restraint caused a dramatic increase in heartrate, though not immediately; maximum HR was reached after approximately 8 min. Average heartrate went from 65.5 beats/min to a maximum of 81.5 (24.5% increase) in adults raised in the lab (n = 19). Using wild-caught adults (n = 77), average heartrates went from 54.9 beats/min to 74.2 (35.5% increase). When restraint was removed, HR declined after ~5 min, and reached baseline 50 min later. The nematode parasite did not affect baseline heartrates in either experiment, but in one, it retarded the heartrate elevation during stress, and in the other, it reduced the overall magnitude of the elevation. While we acknowledge that our results are based on comparisons of beetles with naturally-occurring parasite infections, these results indicate this parasite causes a modest reduction in host cardiac output during acute stress conditions. [ABSTRACT FROM AUTHOR]

Pesticides used for plant protection can indirectly affect target and non-target organisms and are identified as a major cause of insect decline. Depending on species interactions, pesticides can be transferred into the environment from plants to preys and predators. While the transfer of pesticides is often studied through vertebrate and aquatic exposure, arthropod predators of insects may represent valuable bioindicators of environmental exposure to pesticides. A modified QuEChERS extraction coupled with HPLC-MS/MS analysis was used to address the question of the exposure to pesticides of the invasive hornet Vespa velutina , a specialist predator of honey bees. This analytical method allows the accurate quantification of nanogram/gram levels of 42 contaminants in a sample weight that can be obtained from single individuals. Pesticide residues were analyzed in female workers from 24 different hornet nests and 13 different pesticides and 1 synergist, piperonyl butoxide, were identified and quantified. In 75 % of the explored nests, we found at least one compound and in 53 % of the positive samples we could quantify residues ranging from 0.5 to 19.5 ng.g−1. In this study, hornets from nests located in sub-urban environments were the most contaminated. Pesticide residue analysis in small and easy to collect predatory insects opens new perspectives for the study of environmental contamination and the transfer of pesticides in terrestrial trophic chains. [ABSTRACT FROM AUTHOR]

Ladybird beetles/Ladybugs, both adults and larvae, are well-known primarily as predators of aphids (plant lice); however, they also prey upon many other soft bodied insects and eggs of different borers. Laboratory rearing of predatory ladybirds often need a live host particularly aphids. Studies were conducted to check the suitability of live and frozen rose and mustard aphids to rear seven spotted ladybird beetle under two feeding conditions i.e., fed normally (unstarved beetles) or hungry (starved) for 16 hours. Results showed that hungriness may affect the food consumption efficiency. When the beetles were not starved, they showed preference for eating live mustard aphids as compared to frozen (Mean ± SE = 6.24 ± 0.37 live aphids, 4.43 ± 0.40frozen aphids). Similar trend was observed on rose aphids (6.51 ± 0.5 (live aphids) and 4.86 ± 0.49 (frozen aphids)). But the adults in starved condition consumed equal number of live and frozen aphids. During the 1st hour, starved beetles consumed more aphids of both species as compared to unstarved beetles. Also, more number of mealybugs was consumed in starved condition. This study highlights that feeding potential of predatory seven spotted ladybird is not only affected by the type of host but also the condition of host (live vs frozen). Moreover, starvation level of the predator can also be an important factor in determining its devouring capacity. [ABSTRACT FROM AUTHOR]

Alarm signals are widespread in the social insects. It is commonly accepted that such signals produce adaptive short-term aggressive or aversive responses in conspecifics, but the possibility that they could also lead to social learning about predator identity has not yet been addressed. Here we demonstrated that responses to alarm volatiles can lead to social learning about asocial stimuli in honeybees. Using a phototactic assay, we initially confirmed previous findings that alarm volatiles deter individuals from approaching a coloured light. When the same individuals subsequently experienced the coloured light in the absence of alarm volatiles, the same deterrent effect was observed, suggesting that responses to alarm volatiles became conditioned to the coloured light. Previous experience with the light in the absence of alarm cues did not induce this response, nor did previous association of alarm cues with a different coloured light. Our findings highlight that social insect signals can lead to social learning through a simple yet powerful associative mechanism. [ABSTRACT FROM AUTHOR]

It has been reported that Scytodes spiders are predators of spiders of the genus Loxosceles, but the question of the effect of Scytodes globula Nicolet on Loxosceles laeta (Nicolet) populations is still unanswered. The goal of this study is to analyze the population effect of S. globula on the population dynamics of L. laeta by means of simulation with projection matrices, considering the seasonal fluctuation of fecundity, random meetings between the predator and the prey, and limited growth of the L. laeta population. We found that the most important parameters to predict the characteristics of the population at equilibrium are the fertility and the survival function of the spider of advanced developmental stage. Also, the predator S. globula significantly decreases population size, population fluctuations, and the proportion of reproductive individuals of L. laeta. The most probable effect of S. globula on L. laeta populations is a decrease of 20% of the population size. This is insufficient to consider this species as an agent of biological control of L. laeta. However, the action of S. globula is not negligible because decreasing the L. laeta population by about 20% could mean a decrease of about 15% in the incidence of loxoscelism. This action is probably less effective than other epidemiological measures such as house cleaning and insecticides or arachnicides and probably similar to the direct action of humans eliminating one or two spiders per year in their houses, but it helps. [ABSTRACT FROM AUTHOR]

Genetic variations of the two coccinellid predators; Coccinella undecimpunctata L. and Hippodamia variegata (Goeze) within and between distant populations in Saudi Arabia were studied by partial sequencing of three mitochondrial genes i.e., COI gene and ribosomal 12S and 16S. Samples were collected from four distant localities for C. undecimpunctata (Jazan, Jeddah, Taif and Madinah) and from six distant localities for H. variegate (Jazan, Jeddah, Taraba, Madinah, Riyadh and Tabouk). Concatenated sequences (1354 bp) were manipulated by three analytical methods (maximum parsimony, neighbor-joining and maximum-likelihood) producing one fixed tree. The A, C, G and T base compositions were 36.8, 14.5, 10.5 and 38.2%, respectively. The pair-wise genetic distances (D) among the studied populations ranged from 0.0013 to 0.0041 in case of C. undecimpuntata and from 0.0048 to 0.0128 in case of H. variegata. Tree topology did not discriminate among and within populations of both species, except of Tabouk population for H. variegata which showed one cluster of all individuals. It may be concluded that the studied populations of both coccinellids showed low genetic variability. Therefore, this confirms that it has not structured along geographically separated populations in both the studied species; the genetic variability was slightly affected by either fragmentations or ecological factors. [ABSTRACT FROM AUTHOR]

Herbivore-induced plant volatiles (HIPVs) are clues that help predatory insects search for food. The hypothesis that entomopathogenic fungi, which protect plants, benefit from the release of HIPVs was tested. The plant Arabidopsis thaliana was used as the source of HIPVs. The insect herbivore Lipaphis erysimi (Kaltenbach) was used as the inducer, and the fungal pathogen of the aphid Lecanicillium lecanii was exposed to HIPVs to test our hypothesis. When exposed to aphid-induced A. thaliana volatiles, the mortality of aphids pre-treated with a conidial suspension of L. lecanii, the conidial germination and the appressorial formation were significantly increased compared with the control. The decan-3-ol and 4-methylpentyl isothiocyanate that were detected in the headspace seemed to have positive and negative affection, respectively. Moreover, HIPVs generated from groups of eight aphids per plant promoted significantly increased conidial germination and appressorial formation compared with HIPVs from groups of one, two and four aphids per plant. Our results demonstrated that the pathogenicity of the entomopathogenic fungus L. lecanii was enhanced when exposed to HIPVs and that the HIPVs were affected by the number of insect herbivores that induced them. [ABSTRACT FROM AUTHOR]

The formely monotypic Neotropical genus Megalocraerus Lewis is revised to include five species, known from southeastern Brazil to Costa Rica: M. rubricatus Lewis, M. mandibularis sp. n., M. chico sp. n., M. madrededios sp. n., and M. tiputini sp. n. We describe the species, map their distributions, and provide a key for their identification. Their subcylindrical body form and emarginate mesosternum have previously hindered placement to tribe, although their curent assignment to Exosternini now appears well supported by morphological evidence. Nothing is known of the natural history of the species. [ABSTRACT FROM AUTHOR]

Praying mantids have been shown to exert strong influences on arthropod community composition. However, they may not occupy the same trophic level throughout their lives. Trophic shifting over a life cycle could explain the documented variation in results from field studies, but specific interactions of predators within food webs have been difficult to determine simply by comparing control and treatment assemblages in field experiments. We examined the trophic position of the Chinese praying mantid,Tenodera aridifolia sinensis (Saussure), using stable isotope analysis (SIA). We measured the δ13C and δ15N of field-collected arthropods, and of laboratory groups of mantids fed known diets of these arthropods chosen from the most abundant trophic guilds: herbivores (sap feeders and plant chewers), and carnivores. We also collected mantids from the field over a growing season and compared their SIA values to those of the laboratory groups. Both δ13C and δ15N of mantids fed carnivorous prey (spiders or other mantids) were higher than those fed herbivores (grasshoppers). SIA values from field-collected mantids were highly variable, and indicated that they did not take prey from trophic guilds in proportion to their abundances, i.e., were not frequency-dependent predators. Further, δ15N decreased from a high at egg hatch to a low at the third instar as early nymphs fed mainly on lower trophic levels, and increased steadily thereafter as they shifted to feeding on higher levels. We suggest that the community impact of generalist predators can be strongly influenced by ontogenetic shifts in diet. [ABSTRACT FROM AUTHOR]

The functional response and predation parameters of three species of predatory pirate bugs Amphiareus constrictus (Stal), Blaptostethus pallescens Poppius, and Orius tristicolor (White) (Hemiptera: Anthocoridae) were evaluated at four different densities of eggs of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). Experiments were conducted in Petri dishes containing a tomato leaf disk infested with the pest eggs, and maintained inside growth chamber with environmental conditions of 25 ± 2°C, 70 ± 10% relative humidity, and a photoperiod of 12:12 (L:D) h. A. constrictus and B. pallescens showed a type III functional response where predation increased at a decreasing rate after egg density was higher than 12 per leaf disk, reaching an upper plateau of 18.86 and 25.42 eggs per 24 hours, respectively. By contrast, O. tristicolor showed a type II functional response where the number of eggs preyed upon increased at a decreasing rate as egg density increased, reaching an upper limit of 15.20 eggs per 24 hours. The predator equations used in this study estimated handling time of 1.25, 0.87, 0.96 h for A. constrictus, B. pallescens, and O. tristicolor, respectively. The lower handling time and possible higher attack rate of B. pallescens suggests a higher efficiency and probably greater impact on the pest population. If conservation or classical biological control of T. absoluta is to be implemented, then prioritizing which natural enemy species is the most efficient is an important first step. [ABSTRACT FROM AUTHOR]

Beneficial insects (predators, parasitoids, pollinators) associated with stinging nettles, Urtica dioica Linnaeus (Urticaceae), were sampled at three sites in central Washington during spring-summer 2011-2013 using transparent sticky traps attached to upper portions of plants. Large numbers (200-400/trap) of beneficial insects were trapped particularly in June and early July, gradually decreasing thereafter. Phytophagous insects (aphids and leafhoppers) were trapped in much lower numbers (< 20/trap). Predatory bugs, carnivorous flies, parasitic wasps (Pteromalidae, Eulophidae, Trichogrammatidae, Scelionidae) and native bees dominated the trap catches. Predatory bugs were the most abundant beneficial insects trapped in 2 years (2011, 2013) with parasitic wasps dominant in 2012. Minute pirate bugs, Orius spp. (Anthocoridae) were dominant, accounting for > 95% of predatory bugs, peaking in abundance in June or July. Predacious flies were dominated by species of Empididae and Dolichopodidae. Native bees were commonly trapped, especially in 2011 and 2012. The data presented here indicate that stinging nettles in the Yakima Valley of eastern Washington may provide an important habitat for beneficial insects and may have a role to play in enhancing conservation biological control in agricultural crops. [ABSTRACT FROM AUTHOR]

Animal communication is an intriguing topic in evolutionary biology. In this comprehensive study of visual signal evolution, we used a phylogenetic approach to study the evolution of the flash communication system of North American fireflies. The North American firefly genus Photinus contains 35 described species with simple ON-OFF visual signals, and information on habitat types, sympatric congeners, and predators. This makes them an ideal study system to test hypotheses on the evolution of male and female visual signal traits. Our analysis of 34 Photinus species suggests two temporal pattern generators: one for flash duration and one for flash intervals. Reproductive character displacement was a main factor for signal divergence in male flash duration among sympatric Photinus species. Male flash pattern intervals (i.e., the duration of the dark periods between signals) were positively correlated with the number of sympatric Photuris fireflies, which include predators of Photinus. Females of different Photinus species differ in their response preferences to male traits. As in other communication systems, firefly male sexual signals seem to be a compromise between optimizing mating success (sexual selection) and minimizing predation risk (natural selection). An integrative model for Photinus signal evolution is proposed. [ABSTRACT FROM AUTHOR]

Species of infraorder Cimicomorpha of Heteroptera exhibit holokinetic chromosomes with inverted meiosis for sex chromosomes and high variation in chromosome number. The family Reduviidae, which belongs to this infraorder, is also recognized by high variability of heterochromatic bands and chromosome location of 18S rDNA loci. We studied here five species of Reduviidae (Harpactorinae) with predator habit, which are especially interesting because individuals are found solitary and dispersed in nature. These species showed striking variation in chromosome number (including sex chromosome systems), inter-chromosomal asymmetry, different number and chromosome location of 18S rDNA loci, dissimilar location and quantity of autosomal C-heterochromatin, and different types of repetitive DNA by fluorochrome banding, probably associated with occurrence of different chromosome rearrangements. Terminal chromosome location of C-heterochromatin seems to reinforce the model of equilocal dispersion of repetitive DNA families based in the "bouquet configuration". [ABSTRACT FROM AUTHOR]

Individual organisms have to endure transient periods of low-food supply with consequences for growth, reproduction and survival. To resist starvation, animals usually store resources in their bodies: the larger the animals are, the more resources they can carry, but the more energy they need to allocate for maintaining bodily functions. It is unclear how survival relates to body size when food is scarce or absent, and how to characterize individual differences in survival within a population., We use a dynamic energy budget ( DEB) model to describe food acquisition, subsequent reserve dynamics and allocation of reserve to body maintenance, growth and maturation of an aquatic insect predator, Notonecta maculata. In a DEB context, we can assume that starvation-induced death strikes when the reserve of an organism is depleted to a certain extent. The way reserve dynamics change upon starvation might thereby influence the ability to survive in the absence of food. Moreover, individuals in a starved population do not die at the same time, even though they might be of the same body size with similar life histories., To describe individual differences in starvation resistance, we link the reserve dynamics derived from the DEB model to the general unified threshold model of survival ( GUTS). We tested two different special cases within GUTS, individual tolerance ( IT) and stochastic death ( SD), and three different starvation options for their suitability in representing experimental data on body size-related starvation resistance., The DEB model reproduced laboratory data on the development of juvenile N. maculata under different food conditions well and closely predicted the weight loss of individuals during prolonged starvation. Both the combined IT-model and the combined SD-model closely fit survival for different food conditions including starvation. However, the two models make different predictions for survival under repeated transient starvation periods. Our results suggest that larger N. maculata specimens are able to resist starvation to a greater extent than smaller conspecifics., The DEB model provides a mechanistic explanation for the positive relationship between body size and starvation resistance, and offers testable hypotheses for possible deviations from this general trend. [ABSTRACT FROM AUTHOR]

Research of insect fauna in alfalfa fields in the region ofVojvodina has been neglected for more than twenty years. During the second half of the last century, many authors from former Yugoslavia investigated this topic: JOVANIĆ (1957), PETRIK (1959), BALARIN (1974), PROTIĆ (1987), KEREŠI & SEKULIĆ (1994). Despite rich diversity of insect fauna in alfalfa updated data on this topic are lacking, especially on Heteroptera in this crop. This can be explained by the fact that alfalfa makes only 4% ofall crops raised in this region and that mainly pest species of economic importance are emphasized during the years of their mass appearance, exclusively. For this reason the aim ofthis study was to compare situation on heteropteran fauna diversity in alfalfa fields in the region of Bačka, with reference on investigations during the period 1981-1985 and in 2012. Special attention waspaid to changes in bugs' diversity, domination ofspecies and economical threats by certain species. Sampling of Heteroptera was conducted in period from late spring to midsummer, during the period of high activity of bugs with respect of plant-host phenology. Adults were collected with insect net and by hand. Collected specimens were identified in the laboratory at the Faculty of Agriculture Novi Sad according to morphological characters and by using different keys for identification: BEI-BIENKO et al., 1964; PÉRICART, 1987; WYNIGER & KMENT, 2010; PROTIĆ 2011; www.macroID.ru; www.koleopterologie.de, etc. During the five years period ofsampling 18 species belonging to sixfamilies of Heteroptera were registered, while in 2012 there were 26 identified species belonging to nine families. Dominant species in both periods ofsampling were phytophagous species with polyphagous preferences, not strictly related to alfalfa. On the other hand the presence and abundance of predaceous species is also recorded what can be of importance in planning biological control program. Results of this study are an overview ofthe true bugs fauna present in the region of Bačka and represent the contribution to faunistic knowledge of Heteroptera in Serbia. [ABSTRACT FROM AUTHOR]

Body size strongly influences the type and strength of species interactions. Animals with complex life cycles, such as dragonflies, usually go through different stages that include a variation in body size and may involve shifts in their trophic position in the food web. This investigation analyzes the position of the dragonfly Rhionaeschna variegata, in the food web according to its body size, in Andean wetland communities of Northwestern Patagonia (Argentina). The phenology of R. variegata larvae and their potential intraguild predators were studied in wetlands with different hydroperiods. Under controlled experimental conditions, feeding trials were performed to assess the effect of R. variegata on the survivorship of different types of prey. The effects of cannibalism and intraguild predation (IGP) on the survivorship of the small larvae of R. variegata were investigated with and without alternative prey as well as different sympatric predators. The phenology of R. variegata and intraguild predators differed among wetlands. The feeding trials showed that R. variegata has a significant effect on the survivorship of invertebrate and vertebrate prey. Cannibalism increased with body size in odonate larvae. The survivorship of small- and medium-sized larvae was mainly affected by the presence of larger predators such as belosmatids. The field and experimental data show that the effect of IGP and cannibalism is affected by the cohort dynamics of R. variegata. Body size in R. variegata determines the strength of its interaction with other components of the community. [ABSTRACT FROM PUBLISHER]

The striped lynx spider, Oxyopes salticus, is a dominant predator of pests in agricultural crops where pesticides are readily applied. While past research shows pesticides directly affect the mortality of agricultural pest predators, recent research has found that pesticide exposure may cause sublethal effects in these organisms. This study examined how residues of three common pesticides (active ingredients: bifenthrin, carbaryl, malathion) impact courtship behaviour of O. salticus. Males provided with cues left by females readily performed courting behaviours. However, when females left cues on a substrate containing bifenthrin and carbaryl, males were less likely to perform courtship behaviours and did so for less time. While males on the malathion treatment showed a trend for reduced courting, this was not significantly different from the treatment without pesticides. The cue produced by females is unknown in this species. However, our study found males reduced their courting over time, suggesting that the cue is ephemeral and not long lived. This study adds important insight into the growing evidence that pesticides greatly impact the ecology of agricultural pest predators and other non-target organisms by altering their behaviour. [ABSTRACT FROM AUTHOR]

Abstract: Sex-specific patterns of individual growth, resulting in sexual size dimorphism (SSD), are a little studied aspect of the ontogeny related to the evolutionary history and affected by the ecology of a species. We used empirical data on the development of the predatory wasp Symmorphus allobrogus (Hymenoptera, Vespidae) to test the hypotheses that sexual differences of growth resulting in the female-biased SSD embrace the difference in (1) the egg size and the starting size of larva, (2) the larval development duration, and (3) the larval growth rate. We found that eggs developing into males and females have significant differences in size. There was no significant difference between the sexes in the duration of larval development. The relative growth rate and the food assimilation efficiency of female larvae were significantly higher than compared to those of male larvae. Thus, the SSD of S. allobrogus is mediated mainly by sexual differences in egg size and larval growth rate. [Copyright &y& Elsevier]

The article presents a study which focuses on the predatory aggressive behavior of Japanese wood ant Formica japonica towards interspecific insect aimed at investigating the neuronal mechanisms underlying the motivation for such behavior. It examines the important role of biogenic amine in the brain in motivating aggressiveness by using high-performance liquid chromatography (HPLC). The role of the octopaminergic (OAergic) system in inciting such aggressiveness in ant brain is also discussed.

The predatory spined soldier bug, Podisus maculiventris (Say) (Heteroptera: Pentatomidae), is an economically important and highly valued biological control agent. There is substantial information on the biology, ecology, behavior, and rearing of this stink bug. However, virtually nothing is known of its genetic variation, in natural or domesticated populations. To address this lacuna, we used amplified fragment length polymorphism (AFLP) to assess the genetic variability of field and laboratory populations. Four AFLP universal primer combinations yielded a total of 209 usable loci. The AFLP results showed greater genetic variability between populations from Missouri and Mississippi (both USA), and relatively low variability within Missouri populations. We infer little genetic isolation among Missouri field populations and within laboratory populations, but a significant genetic isolation between Missouri and Mississippi populations. [ABSTRACT FROM AUTHOR]

Background: Insect herbivory induces plant odors that attract herbivores' natural enemies. Assuming this attraction emerges from individual compounds, genetic control over odor emission of crops may provide a rationale for manipulating the distribution of predators used for pest control. However, studies on odor perception in vertebrates and invertebrates suggest that olfactory information processing of mixtures results in odor percepts that are a synthetic whole and not a set of components that could function as recognizable individual attractants. Here, we ask if predators respond to herbivoreinduced attractants in odor mixtures or to odor mixture as a whole. Methodology/Principal Findings: We studied a system consisting of Lima bean, the herbivorous mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. We found that four herbivore-induced bean volatiles are not attractive in pure form while a fifth, methyl salicylate (MeSA), is. Several reduced mixtures deficient in one component compared to the full spider-mite induced blend were not attractive despite the presence of MeSA indicating that the predators cannot detect this component in these odor mixtures. A mixture of all five HIPV is most attractive, when offered together with the noninduced odor of Lima bean. Odors that elicit no response in their pure form were essential components of the attractive mixture. Conclusions/Significance: We conclude that the predatory mites perceive odors as a synthetic whole and that the hypothesis that predatory mites recognize attractive HIPV in odor mixtures is unsupported. [ABSTRACT FROM AUTHOR]

Trials were carried out on integrated control of two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acarina: Tetranychidae) on cucumber (Cucumis sativus L.) under greenhouse conditions in two different time periods during 2006 and 2007 in Ankara-Turkey. In these trials three pesticides (hexythiazox: a selective acaricide; bifenthrin: a pyrethroid insecticide-acaricide; and dimethoate: an organophosphate insecticide-acaricide) were used at one-third of the recommended field concentration and combined with the release of the predatory mites, Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acarina: Phytoseiidae). Pesticides combined with predatory mites were more effective in controlling TSSM than pesticides or predatory mites alone. Residues of bifenthrin were very toxic to P. persimilis but less harmful to A. californicus. When TSSM were treated with bifenthrin and P. persimilis, populations remained at a low level. These results indicate that TSSM can be successfully managed on greenhouse cucumbers by a combination of biological and chemical control. [ABSTRACT FROM AUTHOR]

Trial was carried out, under laboratory conditions to evaluation the responses of the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) and predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) as Turkish (Hatay) strain against three pesticides, which were selected from different groups. The responses (mortality, sensitivity) of mite populations against pesticides were estimated by calculation the median lethal concentration (LC50). According to LC50 values, predatory mite, P. persimilis shows oversensitivity for T. urticae against bifenthrin and dimethoate. Toxicity of bifenthrin and dimethoate were classified as harmful effect according to IOBC criteria. Hexythiazox was less toxic than the other pesticides and evaluated as harmless after 24 h and moderately harmful after 72 h to P. persimilis. For this reason, hexythiazox is suitable to suggest in IPM program and ensure the preservation of predatory strain into local agro-system. [ABSTRACT FROM AUTHOR]

1. Resource competition and intra-guild predation (IGP) are important determinants of the structure of aphidophagous guilds. The likelihood and outcome of IGP is influenced by the density of extra-guild prey and the characteristics of the species involved. 2. The nature of intra-guild interactions between alien and indigenous coccinellids often determines the success of coccinellid invasions, as exemplified by Adalia bipunctata in Japan and Harmonia axyridis in North America and Europe. 3. Harmonia axyridis has negatively impinged on indigenous species in its introduced range, and its recent arrival in Britain poses a threat for members of native aphidophagous guilds. IGP and inter-specific competition between H. axyridis and British coccinellids are predicted to occur. However, the results of such interactions have been little studied. 4. Here we investigate the effects of different diets, designed to mimic possible conditions in the wild, on the survival, development, and adult size of H. axyridis and A. bipunctata. Results demonstrate a skew in the consequences of IGP between the two species: the supplementation of a limited aphid diet with non-conspecific eggs leads to a significant advantage for H. axyridis in respect of all parameters assessed, but gives no benefit to A. bipunctata. 5. We conclude that IGP of A. bipunctata by H. axyridis will contribute to the spread and increase of H. axyridis in Britain. 6. We further conclude that the skewed nature of IGP between A. bipunctata and H. axyridis at least in part explains the limited spread of A. bipunctata in Japan. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Entomologist is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Predatory insects that depend upon particular prey animals are commonly regulated by the prey animal’s abundance. Nymphs of the giant water bug Kirkaldyia (= Lethocerus) deyrolli (Heteroptera: Belostomatidae) are predators regarded as specialists in feeding on tadpoles. We studied the ontogenetic diet shift of aquatic nymphs by quantifying instar abundance and by analyzing captured prey and prey relative abundance during the period of rice irrigation in three localities. We also evaluated the contribution of major prey items (tadpoles, frogs, and Odonata nymphs) on specific growth rates of each nymphal stage in a rearing experiment. First to third-instar nymphs of K. deyrolli fed mainly on tadpoles, regardless of differences in prey availability. Nymphs of subsequent fourth and fifth instar stages shifted from tadpoles to other prey animals within each rice field. A rearing experiment demonstrated that giant water bug nymphs provided with tadpoles had greater specific growth rates at all nymphal stages, except for the final stage, than nymphs fed other prey (frogs and Odonata nymphs). The emergence of young K. deyrolli nymphs seemed to coincide with the period during which tadpoles became abundant in the rice fields. Consumption of tadpoles seems important to allow the nymph to complete its larval development in an unstable temporary habitat. [ABSTRACT FROM AUTHOR]

Nephila clavipes (Linnaeus 1767) and N. pilipes (Fabricius 1793) juveniles exposed to a novel and potentially dangerous prey item frequently attack using thrown silk. To quantity the frequency with which N. clavipes opt to use thrown silk. naive hand-reared small N. clavipes juvenile females were observed attacking a new prey type, stingless bees. Repeated exposure to the stingless bees suggests that the spiders incorporate prior experience into prey attack strategies, as experienced spiders attacked using the more usual Nephila long-bite. [ABSTRACT FROM AUTHOR]

We evaluated the suppression of the confused flour beetle, Tribolium confusum, by the anthocorid bug Xylocoris flavipes and the reduviid bug Amphibolus venator. Four treatments were tested: X. flavipes adults, A. venator adults, X. flavipes adults and A. venator adults released, and control (no predators). After 25 days, X. flavipes alone showed 96.9% suppression of T. confusum, A. venator alone showed 76.2% suppression and both the predatory bugs together showed 95.6% suppression. The rates of loss of whole-wheat flour as an index of damage caused by T. confusum were 2.7%, 6.4%, 3.6% and 11.7% in X. flavipes adults, A. venator adults, X. flavipes adults and A. venator adults released, and control respectively. Furthermore, A. venator attacked X. flavipes adults but not X. flavipes nymphs. The possibility of using both X. flavipes and A. venator against T. confusum is discussed. [ABSTRACT FROM AUTHOR]