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Over the past 30 yr, multiple species of predatory Coccinellidae, prominently Coccinella septempunctata L. and Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) have spread to new continents, influencing biodiversity and biological control. Here we review the mechanisms underlying these ecological interactions, focusing on multi-year field studies of native and non-native coccinellids and those using molecular and quantitative ecological methods. Field data from Asia show that H. axyridis, C. septempunctata, and Propylea japonica (Thunberg) (Coleoptera: Coccinellidae) are regularly among the most abundant predatory species but their rank varies by habitat. Studies of these species in their native Asian range, primarily related to their range in mainland China, document different patterns of seasonal abundance, species specific associations with prey, and habitat separation. Intraguild predation is well documented both in Asia and in newly invaded areas, and H. axyridis benefits most from this interaction. Harmonia axyridis also seems to rely more on cannibalism in times of prey scarcity than other species, and relatively sparse data indicate a lower predation pressure on it from natural enemies of coccinellids. Declines in the abundance of native coccinellids following the spread and increase of non-native species, documented in several multi-year studies on several continents, is a major concern for native biodiversity and the persistence of native coccinellid species. We suggest that future studies focus more attention on the community ecology of these invasive species in their native habitats. China Scholarship CouncilChina Scholarship Council; National Key R&D Program of China [2017YFE0104900]; National Institute of Food and Agriculture, United States Department of Agriculture, Hatch Program [1008480] Published version We thank the China Scholarship Council for a scholarship supporting H. Li's research in the Department of Entomology at the University of Kentucky. This work was supported by the National Key R&D Program of China (2017YFE0104900, to B. Li). J.J.O. was supported by the National Institute of Food and Agriculture, United States Department of Agriculture, Hatch Program under accession number 1008480.

A standardized laboratory procedure tested the limb regeneration abilities of 18 populations (16 species) of lady beetles which were then scored, relative to unoperated controls, based on survival, the proportion regenerating the limb completely or partially, and the magnitude of developmental costs (delayed development, reduced body size) associated with limb ablation. Newly molted fourth instar larvae each had a single foreleg amputated at the base of the femur. All species except Propylea dissecta (Mulsant) showed some complete limb regeneration, with limb regeneration index (LRI) scores ranging from 0.025 to 0.905 out of a possible 1.00 (mean = 0.598). Eriopis connexa Germar, an aphidophagous neotropical species, scored the highest. Widely distributed species that dominate agricultural habitats all scored above 0.75, and the only herbivore, Henosepilachna argus (Geoffroy), scored second from lowest. Prolonged pupal development was the most common cost, occurring in nine species, and correlating negatively with regeneration. Taxonomic distance between species correlated with regeneration, but explained

Predaceous lady beetles are important natural enemies of many insect pests in agro-ecosystem. The altered agricultural practices associated with widespread adoption of Bt cotton may have potential effects on the spatio-temporal patterns of predaceous lady beetles, as the composition and abundance of nontarget sucking pests have been changed in Bt cotton fields. In the current study, the spatio-temporal patterns of two important lady beetles, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) and Propylea japonica (Thunberg) (Coleoptera: Coccinellidae), were surveyed in Bt cotton fields. A nonparametric method associated with Monte Carlo tests was used to address and test whether niche segregation occurred between H. axyridis and P. japonica. The results showed that the dominant region occupied by P. japonica was toward northeast across the season, whereas H. axyridis had higher presence to the southwest. The temporal patterns of H. axyridis and P. japonica also differed significantly, and the highest levels of each species occurred in different locations from each other on each sampling date in the same Bt cotton fields. In total, there were strong spatio-temporal separation patterns between these two species in Bt cotton fields. These spatio-temporal patterns may produce complementary impacts on prey, and this in turn could be used to strengthen the biological control of insect pests by these two lady beetles.

Recent detections of adults of three previously common, native species of lady beetles [Coccinella novemnotata Herbst, Coccinella transversoguttata richardsoni Brown, and Adalia bipunctata (L.); Coleoptera: Coccinellidae] during surveys at several sites in western South Dakota and western Nebraska provided impetus for additional sampling of lady beetles in that region. The current study systematically sampled for lady beetles among three dominant habitats in the region in 2010 and 2011. Four techniques (sucrose-baited and nonbaited yellow sticky traps, sweepnetting, visual searches) sampled 4,036 adult and 830 larval coccinellids comprising 10 species. Coccinella septempunctata L., Hippodamia convergens Guerin-Meneville, Hippodamia parenthesis (Say), and Brachiacantha albifrons (Say) were the most common species. C. novemnotata ranked fifth in abundance, with 94 sampled in small grains, 20 in alfalfa, and 5 in grassland pasture; 58 larval C. novemnotata were sampled primarily in small-grain field...

The coccinellid Tenuisvalvae notata (Mulsant) (Coleoptera: Coccinellidae) has been observed recently in association with the striped mealybug Ferrisia virgata Cockerell (Hemiptera: Pseudococcidae) and the false cochineal scale Dactylopius opuntiae Cockerell (Hemiptera: Dactylopiidae) in the semiarid region of Pernambuco, Brazil. The latter species are important pests of cotton and prickly pear, respectively. In this study, we tested the two scale insects as prey for T. notata. In addition, eggs of Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) were tested as possible alternative prey for rearing T. notata. In this work, the survivorship, reproduction, and predation of T. notata were investigated. The coccinellid T. notata was able to complete development only on F. virgata with 83% larval and pupal viability. Females of T. notata fed F. virgata produced 7.6 eggs a day with an eclosion rate of 61.9%. No oviposition occurred while feeding on A. kuehniella eggs. The highest consumption rate of F. virgata occurred during the last larval instar. Our results support the use of T. notata as an agent for the biological control of F. virgata, a highly polyphagous pest worldwide.

Species of the Afrotropical genus Tropha Weise are revised, diagnosed, and illustrated. Solanophila vigintiduoguttataWeise, 1915, is removed from synonymy with Tropha variabilisWeise, 1900, and its status as a valid species of Tropha (Tropha vigintiduoguttata) is confirmed. Tropha obscura (Korschefsky 1929) is synonymized with T. variabilisWeise, 1900, syn. nov. A neotype of S. vigintiduoguttataWeise, 1915, is designated. A new species Tropha zambiensis sp. nov. is described. A key to the species of Tropha is presented.

The dynamics of predator-prey systems are strongly affected by the predators feeding rate on increasing prey density, that is, its functional response. Holling's assumptions concerning the biological process of handling time, that is, the time a predator spends on pursuing, subduing, eating, and digesting its prey, have been debated, as digestion represents a background component of predation. Therefore, predators are characterized either as digestion or handling limited. A study was initiated to identify the mechanism that limits the coccinellids' predation ability. The 14-spotted ladybird beetle, Propylea quatuordecimpunctata (L.) (Coleoptera: Coccinellidae), and its prey, Aphisfabae Scopoli (Hemiptera: Aphididae), were used in long- and short-term functional response experiments. Results showed that P. quatuordecimpunctata adults exhibit a type II functional response. The estimated attack rates and handling times differed significantly between long- and short-term experiments, indicating that the digestion process limits predation ability of P. quatuordecimpunctata.

The temperature-dependent development of five psyllophagous ladybirds, Adalia bipunctata (L.), Coccinella undecimpunctata aegyptica (Reiche), Exochomus nigripennis (Erichson), Hippodamia variegata (Goeze), and Oenopia conglobata contaminata (Menetries) (Coleoptera: Coccinellidae), was studied on the common pistachio psylla, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae), in the laboratory. The lower developmental thresholds for total development (egg to adult) of the predators ranged from 10.9 (O. c. contaminata) to 14°C (C. u. aegyptica). The lowest and highest degree-day (DD) requirement values for total development of the studied cocinellids were estimated for C. u. aegyptica (166.67 DD) and E. nigripennis (344.83 DD), respectively. The optimum temperature for development of the studied ladybirds, calculated using third-order polynomial and Lactin models, was in the range of 27.5–30°C. This study showed that all the five psyllophagous ladybirds successfully complete their development in a wide range of temperatures from 17.5 to 30°C, indicating their high potential for use in biological control programs against A. pistaciae.

A life table analysis of the 14-spotted ladybird beetle, Propylea quatuordecimpunctata L. (Coleoptera: Coccinellidae), reared on bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae), was conducted at four constant temperatures (17, 20, 25, and 30 ± 1°C). A temperature dependence in the coccinellid's net reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time, and doubling time was detected. Estimated values of intrinsic rate of increase were 0.065, 0.095, 0.166, and 0.190 females per female per day at 17, 20, 25, and 30°C, respectively, where Lactin model indicated that the maximum value is achieved at 29.23°C. Females of ≈75, 50, 45, and 20 d old reach their maximum reproductive potential at 17, 20, 25, and 30 ± °C, respectively. In addition, temperature affected the risk of death of immature and female adults, as the survival curves at the examined temperatures were significantly different. The mean survival times decreased from 19.9 to 8.0 d and 123.1 to 33.5 d from 17 to 30°C for entire immature stages and female adults, respectively.

Divergent natural selection on different host plants may be a crucial factor in promoting the remarkable diversity of phytophagous insects, and might occur in any geographical context. Because the intensity and consequences of divergent selection on different hosts can vary depending on the degree of gene flow between conspecific insect populations, elucidating the geographical context and degree of host specificity in the incipient phase of differential host use is indispensable to understanding the diversification process in phytophagous insects. Henosepilachna diekei Jadwiszczak & Węgrzynowicz (Coleoptera: Coccinellidae) is a tropical ladybird beetle occurring mainly on two host species from different plant families, Asteraceae and Lamiaceae. We investigated the geographical distribution of H. diekei across Java, Indonesia, in relation to the availability of the two hosts, and examined the host specificity of beetles in the laboratory. We also investigated genetic relationships among local populations of beetles using mitochondrial NADH dehydrogenase subunit 2 gene sequences. Geographic variation in host use by H. diekei was largely determined by skewed geographical distributions of the hosts, although there was a synergistic effect with extremely divergent host specificity by the beetles. The molecular analyses suggested that genetic differentiation among the beetle populations has occurred and has been maintained by the effects of both geographical distance and divergent host specificity. The geographical distribution of H. diekei populations differing in host specificity suggests that geographical distance, local host-plant availability, and divergent host specificity contribute synergistically to promote the genetic differentiation and subsequent diversification of phytophagous insects on different hosts.

The effect of temperature on the development, survival, longevity, and fecundity of the 14-spotted ladybird beetle, Propylea quatuordecimpunctata L. (Coleoptera: Coccinellidae) reared on bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae) was determined at six constant temperatures (17, 20, 25, 30, 32.5, and 35 ± 1°C) in the laboratory. Results showed a temperature—dependent development of the coccinellid. An appropriate linear model indicated that 218.0 degree days above a threshold of 10.2°C were needed to complete immature development from egg to adult emergence. Data were fitted to the nonlinear Briere model, which for total immature period estimated the upper developmental threshold at 36.0°C, the lower threshold at 12.2°C and the temperature for maximum developmental rate at 30.3°C. Survival of immature stages varied significantly across temperatures with the lowest survival of just 14% occurring at 32.5°C and the highest (96%) at 25°C. In addition temperature showed a profound effect on female longevity over this viable range of temperatures, as it decreased from 123.06 d at 17°C to 33.53 d at 30°C. The highest fecundity (724.6 eggs/female) was recorded at 25°C. These results might be useful tools for the prediction of P. quatuordecimpunctata phenology and the interaction with its prey.

The predator Diomus seminulus (Mulsant) has been found frequently on forage grasses feeding of Sipha flava (Forbes), suggesting that it is a natural predator of this aphid and has potential as a biological control agent for this pest in Brazil. The objectives of this study were to evaluate the effect of temperature on biological aspects of D. seminulus and to determine whether odor is used by this predator to locate prey on forage grass infested with S. flava. We performed daily evaluations of the viability and duration of each instar of the larval and pupal stages at 16, 20, 24, and 28°C. The reproductive capacity and longevity of adults were estimated at 24°C. The use of odor by D. seminulus to search for aphids was evaluated using a Y-tube olfactometer. The average duration of the embryonic period, each instar, larval, and pupal stages decreased significantly with increasing temperatures from 16 to 24°C. Eggs were blackened and parched, leading to low viability at 16 and 28°C. However, viability of the instars and larvae were not significantly affected by temperature. Adults of D. seminulus survived for >135 d; however, peak oviposition occurred 20–50 d after emergence, suggesting that this is the ideal duration of adult maintenance in laboratory culture. The predator D. seminulus used the odors from aphid prey or volatile compounds released from attacked plants to locate their prey. These results provide support for the use of D. seminulus as a successful biological control for aphids.

Reproductive schedules are a critical aspect of life history intrinsically linked to a species' ecology. We explored dynamic trajectories of daily fecundity, egg size, and egg fertility in three size classes of Hippodamia convergens Guerin-Meneville produced by varying larval access to food, eggs of Ephestia kuehniella Zeller. Adult pairs were held with ad libitum food and eggs were collected daily, counted, and a subsample measured. Egg fertility declined steeply over 25 clutches in small females, gradually in large females, but remained relatively stable in medium females. In small females, egg size and daily fecundity declined in a linear manner. There was no clear indication of an egg size-number tradeoff. In medium females, both egg size and daily fecundity peaked around the 16th day of oviposition, after which both declined. Large females began oviposition earlier and achieved peak egg size about day 7, and peak fecundity around day 12. Large females thus expressed a larger proportion of their reproductive effort early in adult life, a strategy inferred to be adaptive in the context of aphidophagy; a larger proportion of progeny would develop early in the exponential growth phase of the prey population when food is most abundant. Increases in egg size during this period may improve the survival of later-developing progeny; prey become scarce as aphid outbreaks decline and competition intensifies, favoring offspring with a larger body size at eclosion. Larval diet restriction appeared to constrain these presumably adaptive changes in egg size and daily fecundity, largely through effects on maternal body size.

We examined reciprocal intraguild predation (IGP) and cannibalism among various combinations of Coleomegilla maculata DeGeer and Chrysoperla cornea Stephens larvae as they developed feeding on greenbugs, Schizaphis graminum Rondani, on sorghum plants in microcosms. Pairs of C. maculata larvae suppressed aphids better than pairs of C. carnea larvae or heterospecific larval pairs and yielded the highest rate of plant survival. IGP by C. carnea larvae occurred mostly in the first instar, whereas C. maculata larvae were more aggressive in later instars. Although C. carnea was the superior intraguild predator, winning 62.7% of contests in microcosms, this value increased to 88.9% when the experiment was repeated in petri dishes without plant material, regardless of whether greenbugs or eggs of Ephestia kuehniella Zeller were offered as focal prey. Provision in petri dishes of the sessile, higher quality prey (Ephestia) as opposed to greenbugs, improved the survival of solitary larvae and delayed cannibalism and IGP until later developmental stages in both species. Larvae of C. maculata that cannibalized took longer to develop and weighed less at pupation, independent of the arena or prey offered. Although larvae of C. carnea did not pay a cost for cannibalism or IGP in microcosms, there were some negative developmental effects of IGP in petri dishes, particularly on the Ephestia diet. These results illustrate how the plant, as a substrate, can mediate the strength of IGP interactions and how the relative suitability of the focal prey can influence both the timing and consequences of cannibalism and IGP.

The multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is an invasive species in North America that has a low susceptibility to indigenous natural enemies. We investigated the role of the immune system of H. axyridis in its resistance to North American population of the hymenopteran parasitoid Dinocampus coccinellae Schrank. An ultrastructural study of adult H. axyridis hemocytes under electron and light microscopy identified five different cellular types: plasmatocytes, granular hemocytes I, granular hemocytes II, oenocytoids, and spherule cells. Only granular hemocytes II and plasmatocytes are involved in the nodulation of bacteria and encapsulation of parasitoid eggs. Injection of Sephadex beads in H. axyridis adults induces an innate immune response and results in complete encapsulation of ≈28% of the beads after 24 h and 81% after 5 d. When H. axyridis was parasitized by D. coccinellae, we observed a decrease in the encapsulation response, and this pattern was inversely related to the number of parasitoid eggs in the H. axyridis hemolymph. The injection of polydnaviruses by D. coccinellae females and the multiple target hypotheses could both explain the encapsulation rate decreasing with increasing parasitoid egg load. Our results suggest that the immune system of H. axyridis could favor its escape from internal developing natural enemies indigenous to North America.

Intercropping is a traditional agronomic practice, and when properly managed, it can significantly contribute to pest control. The current study investigates the severity of plant damage related to infestation by the cotton aphid, Aphis gossypii Glover (Hemiptera: Heteroptera: Aphididae) and its predation by spotless ladybird beetle, Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae) and green lacewing, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and parasitism by Lysiphlebus testaceipes (Cresson) (Hymenoptera: Aphidiidae) in sole cotton plots and in plots of cotton intercropped with fennel. Cotton aphid populations were significantly higher in sole cotton plots than in intercropping plots for plots that were not treated with insecticide. The percentages of losses in cotton seed yield were higher in the sole cotton plots than in the four intercropping systems (one row of cotton for two rows of fennel, one row of cotton for three rows of fennel, two rows of cotton for one row of fennel, and three rows of cotton for two rows of fennel). The losses in cotton seed yield were significantly lower in the intercropping system with three rows of cotton interspersed with two rows of fennel than in the other intercropping systems. Spotless ladybird beetle and green lacewing densities were significantly higher in the intercropping system with three rows of cotton interspersed with two rows of fennel than in the other intercropping systems. These results are of practical significance in designing appropriate strategies for cotton aphid control in cotton-fennel intercropping systems.

Among the methods to evaluate field diets of insect predators is frass analysis. The potential of this infrequently used method was explored for determining prey consumption by adult ladybird beetles (Coleoptera: Coccinellidae) in alfalfa, Medicago sativa L., fields. A laboratory experiment revealed that at 20°C, within 48 h after consumption of prey [either pea aphids, Acyrthosiphon pisum (Harris), or larvae of the alfalfa weevil, Hypera postica (Gyllenhal)], almost all prey fragments had been voided by adults of five ladybird beetle species commonly occurring in Utah alfalfa fields. Among the five ladybird beetle species, aphid and weevil fragments were detected in frass of 80–95 and 29–73% of adults, respectively. A second laboratory experiment with adults of the most common of these predators (the introduced Coccinella septempunctata L.) more fully identified and enumerated diagnostic fragments for specific types of prey (aphids, weevil larvae, and conspecific larvae) as they occurred in frass. Frass pellets from the consumption of alfalfa weevil and conspecific larvae most often contained diagnostic cuticle and setae, and less often mandibles and head capsules. Frass from the consumption of pea aphids most often contained antennae and legs, and less often mouthparts, eyes, and tarsal claws. These laboratory results provide a foundation for using and interpreting the results of frass analysis as a technique to assess field diets of aphidophagous ladybird beetles in alfalfa.

Reproductive potentials were compared for a large invasive lady beetle, sevenspotted lady beetle, Coccinella septempunctata L. (Coleoptera: Coccinellidae), and a set of four smaller native North American species that have been displaced from alfalfa, Medicago sativa L., fields in Utah. The invader rapidly attained predominance in these fields during years when aphid populations were high. In a laboratory experiment, females were provided with excess numbers of their principal prey in these fields, pea aphids, Acyrthosiphon pisum (Harris). Among the five species, both the number and total volume of eggs (number × mean egg volume) produced per day increased with increasing female size and were greatest for C. septempunctata. Rates of reproduction also increased with increasing female size within species. Similarly sized females of C. septempunctata and transverse lady beetle, Coccinella transversoguttata richardsoni (Brown), laid similar total volumes of eggs per day, but females of the invasive species had more ovarioles and laid larger numbers of individually smaller eggs. In summary, when feeding on abundant prey in a habitat in which it predominates, the invasive C. septempunctata gains reproductive advantage over native, North American lady beetles, from its large body size and its investment in many small eggs. The results support the generalization that high fecundity linked with large body size may often be one important factor that promotes the dominance of introduced species over native competitors in resource-rich environments.

The establishment of exotic coccinellid species may be related to the decline in native coccinellid species within the United States. Coccinellids may interact indirectly by competing for shared resources and directly through intraguild predation. Prior studies have examined pairwise interactions among species and although several coccinellid species typically co-exist within habitats, multi-species interactions have rarely been investigated. To examine how aphid prey levels influence interspecific interactions among a multispecies assemblage, the exotic coccinellids, Harmonia axyridis (Pallas) and Coccinella septempunctata (L.) (Coleoptera: Coccinellidae), and a native coccinellid species, Coleomegilla maculata (DeGeer) (Coleoptera: Coccinellidae), were paired or placed in groups containing three heterospecific larvae and fed 2.4, 12.0, or 24.0 mg of aphids per larva daily. Larval survival, developmental time, and adult weight of individuals were measured. Greater amounts of prey typically resulted in increased adult weights and shorter developmental times. When Coleomegilla maculata and Coccinella septempunctata were paired, Coleomegilla maculata had higher survival rates at low prey levels and Coccinella septempunctata had higher survival at mid- and high prey levels. When the three species were combined, Coccinella septempunctata and Coleomegilla maculata had similar survival rates (17%) at low prey levels; at mid- and high prey levels, Coccinella septempunctata survival increased (58–88%), but Coleomegilla maculata survival remained similar (17–21%). Survival of H. axyridis was not affected by competitors. Even though intraguild predation occurs among these species, the responses to competitors varied based on prey level, coccinellid species, and the number of interacting larvae.

Biological control of powdery mildew (PM) plant pathogens may offer a solution to chemical control problems such as resistance, worker safety, and effects on nontarget organisms. Unfortunately, mildew consumption by arthropods is seldom studied and poorly understood. The coccinellid tribe Halyziini is composed entirely of obligate consumers of various PM fungi and is represented in the Western Hemisphere by members of the genus Psyllobora Chevrolat. In western North America Psyllobora vigintimaculata Say feeds on PM in natural and managed systems. Here, we report the insect's biology and phenology through the use of a laboratory colony, rectangular degree-day calculation and field sampling in an urban landscape. The natural presence of this beetle in Davis, CA, has been documented over the course of 2 yr through weekly presence-absence and density sampling of native and exotic plants prone to PM. Sampling data indicates activity from late February through mid-December. The insect was observed feeding on the PM of >25 plant species in 13 different plant families. There is a positive relationship between PM severity and the relative density of insects, suggesting an aggregative numerical response. The potential of P. vigintimaculata for biological control and the possibility of using this insect as an indicator of PM in horticultural systems are both discussed.

The life cycle, morphology, and potential of Diomus terminatus Say (Coleoptera: Coccinellidae) to control the sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), were examined in the laboratory. The morphologies of first and fourth instars are described and illustrated, with emphasis on characters of first instar that differ from those of later instars. Dramatic differences exist in the relative size and abundance of specialized setae between early and late instars. Field-collected late instars of D. terminatus were successfully reared to adult stage at 26°C by using M. sacchari feeding on small pieces of sugarcane {Saccharum, spp.) leaves. The eggs laid on the sugarcane leaves hatched in 4.5 ± 0.1 d. Larval and pupal stages lasted an average of 6.8 ± 0.6 and 4.9 ± 0.2 d, respectively. D. terminatus required 12.1 ± 0.6 d from egg hatch to adult emergence. The adult longevity test with single adults in petri dishes revealed that D. terminatus remained alive for 26 ± 1.9 d when feeding on aphids of mixed ages. The larvae consumed a total of 30 ± 1.8 aphid nymphs, with a daily consumption rate of 4.7 ± 0.4. The adult voracity test showed that D. terminatus could consume as many as 19 ± 0.9 aphids per d. These results are discussed with respect to their implications for aphid control in Louisiana sugarcane.

Several studies suggest the possibility that non-native lady beetles may have replaced native lady beetles in some agricultural habitats. There is relatively little information, however, about lady beetle species composition outside of agricultural habitats. Evans (2004) suggested that native species have retreated to nonagricultural habitats in response to the arrival of non-native lady beetles (habitat compression hypothesis). To test this hypothesis, a survey of lady beetles was conducted in 2004 and 2005 in different habitats in Maine. From May to October, lady beetles were sampled in a variety of agricultural and nonagricultural habitats. In total, 3,487 and 2,903 lady beetles were collected in 2004 and 2005, respectively. Non-native lady beetles were found in a variety of habitats, including the habitats that would have likely served as a refuge for native species if the habitat compression hypothesis applied to the surveyed areas. Native species were found in a higher proportion in agricultural habitats compared with nonagricultural habitats and in very low numbers in all of the habitats surveyed. Hippodamia tredecimpunctata tibialis (Say) and Coccinella transversoguttata Brown, the two native species that were once dominant here, made up only 1.09 and 0.07% of the total lady beetles collected, respectively. In this survey, we failed to detect evidence that native lady beetles have retreated to nonagricultural habitats in response to the arrival of non-native lady beetles.

There is increasing evidence that Aphis glycines Matsumara (Hemiptera: Aphididae) populations are negatively impacted by endemic natural enemies within North America. In Iowa, surveys of natural enemies in soybean, Glycine max (L.) Merr., conducted before the arrival of A. glycines revealed a number of species that may contribute to their mortality. We used several sampling methods to determine the diversity of the natural enemy community in Iowa soybean since the arrival of A. glycines. Natural enemies were collected using field-counts (in situ sampling), destructive counts, sweep-net sampling, and yellow-sticky cards. When predaceous arthropods were combined across all sampling methods, six orders were identified, including nine families and 13 genera. In comparison with a similar study conducted 26 yr ago, we observed fewer native coccinellids with the most abundant being the exotics Harmonia axyridis (Pallas) and Coccinella septempunctata L. (Coleoptera: Coccinellidae). Combining all foliar-b...

Delphastus catalinae (Horn) (Coleoptera: Coccinellidae) is a predator of whiteflies. It is tropical in origin. Whiteflies cause problems in agriculture in both humid and arid environments. A study was conducted to determine any effects of relative humidity on oviposition, hatching, and survival of immature D. catalinae. Comparative tests were conducted among relative humidities of 25, 35, 50, and 85% and between 10 and 85% RH. All tests were conducted at 26°C; hence, vapor pressure deficits ranged from 5.04 to 30.25 mb. The study was conducted using the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius), as the host insect, which was reared on collard, Brassica oleracea ssp. acephala de Condolle. Egg hatch and survival to the adult stage were reduced at the lower relative humidities. At 85% RH, 99% of the eggs hatched and ≈90% of the beginning cohort survived to the adult stage. Conversely, ≈85% hatched and ≈60% survived to the adult stage at 25% RH, whereas 50% survived to the adult stage at 10% RH. Eggs required more time to develop at 10% RH (5.3 d) compared with 85% RH (4.1 d); a test was not set up to compare the developmental times for the larval and pupal stages. Weights of male and female D. catalinae were significantly reduced with a reduction in humidity. The results also suggest that density of immature D. catalinae, limited food supply, or both may affect survival and size of the ensuing adults. These results help in the understanding of the ecology of D. catalinae, and they indicate that extremes in ambient moisture can have an impact on the population of this predator.

The coccinellid-specific parasitic fungus Hesperomyces virescens Thaxter was found on the multicolored Asian lady beetle, Harmonia axyridis (Pallas), in fall and winter in Lebanon County, Pennsylvania. Research objectives were 1) to determine the density of H. virescens on field-collected H. axyridis adults held in the laboratory, and 2) to determine H. virescens presence, density, and distribution on H. axyridis adults in the field. In the laboratory, male and female H. axyridis adults hosted >150 H. virescens mature thalli (i.e., fruiting bodies); distributed primarily on the elytra and abdomen. At the overwintering site, H. virescens density per host was often

Maternally inherited bacteria that kill male but not female hosts during embryogenesis occur in Harmonia axyridis (Pallas). In two populations in Japan, Fukuyama, Hiroshima, and Muikamachi, Niigata, H. axyridis were infected with male-killing bacteria. According to the sequence analysis of the gene fragment for 16S rDNA, these bacteria belong to the genus Spiroplasma. Tetracycline-treated infected females produced female and male progeny, although untreated females produced only female progeny, demonstrating that H. axyridis is male-killed by the Spiroplasma. The proportion of females infected in Muikamachi and Fukuyama was 0.039 and 0.135, respectively, indicating that prevalence of male-killer in H. axyridis is low in Japan.

We examined the nature of sibling egg cannibalism behavior and its developmental consequences in three aphidophagous Coccinellidae that all lay clustered eggs: Cycloneda sanguinea L., Harmonia axyridis (Pallas), and Olla v-nigrum Mulsant. There was variation among species in the proportion of eggs laid singly versus in clusters (C. sanguinea > H. axyridis ≈ O. v-nigrum), the synchrony of egg hatch within clusters (H. axyridis > C. sanguinea ≈ O. v-nigrum), and the proportion of eggs cannibalized by early-hatching larvae (O. v-nigrum > C. sanguinea > H. axyridis). Single eggs were cannibalized at lower rates than clustered eggs in all three species, and cannibals delayed dispersal from clusters until all unhatched eggs were consumed. In all three species, the number of eggs cannibalized was negatively correlated with the proportion hatching synchronously (within 10 min). Egg cannibals survived to adulthood at the same rate as noncannibal larvae in H. axyridis and O. v-nigrum, and at a higher rate ...

To explore the relationship between spiders and insects in agroecosytems, we ran two laboratory experiments to determine if pest insects reduced their foraging activity in the presence of spiders or cues left by spiders. First, we quantified the damage to soybean leaves [Glycine max L. (Merrill); Fabaceae] caused by Japanese beetles [Coleoptera; Scarabeidae; Popilliae japonica (Newman)] and Mexican bean beetles [Coleoptera; Coccinellidae; Epilachna varivestis (Mulsant)] in the presence of either the tangle weaver, Achaearanea tepidariorum (C.L. Koch) (Araneae; Theridiidae), or the orb weaver, Arigope trifasciata (Forskal) (Araneae; Araneidae). Although most beetles survived, they consumed less of the soybean leaf than the beetles in control containers with no spiders. In a second experiment, we attempted to determine if Japanese beetles responded to the cues (e.g., silk draglines and feces) left by three species of wolf spider [Araneae; Lycosidae: Pardosa milvina Hentz, Rabidosa rabida Walckenaer...

We used scanning and transmission electron microscopy in a morphological examina- tion of the antennae of two specialist predators of the exotic hemlock woolly adelgid, Adelges tsugae Annand, as an initial step toward understanding the potential importance of olfaction in host-Þnding behavior. Laricobius nigrinus Fender (Coleoptera: Derodontidae) possesses six types of sensilla on a relatively long antennae comprised of scape, pedicel, and nine annuli. Two types of basiconic sensilla contained numerous wall pores with branching pore kettles and were located on the terminal three annuli. The terminal annulus contained a placoid-like sensillum, and the penultimate and antepen- ultimate annuli contained a coeloconic-type sensillum forming a ring around the distal portion. Two types of sensilla chaetica were located along much of the length of the antennae. Pseudoscymnus tsugae Sasaji and McClure (Coleoptera: Coccinellidae) was found to possess Þve types of sensilla on an extremely short antenna, which is characteristic of the tribe Scymnini, consisting of scape, pedicel, and seven annuli. Three of the annuli were void of sensilla. Two types of sensilla chaetica were located on the scape and pedicel, as well as the terminal annuli. Three types of basiconic sensilla, one of which contained numerous wall pores, were identiÞed on the terminal two annuli. No sexual dimorphism was detected on either predator species. Our results suggest that olfaction is a more important sensory modality in L. nigrinus than P. tsugae, and that trap-based sampling methods incorporating olfactory cues are more likely to be successful for L. nigrinus than P. tsugae.

Adult and larval aphidophagous lady beetles (Coleoptera: Coccinellidae) feed on alfalfa weevil larvae, Hypera postica (Gyllenhal), and aphids in alfalfa fields. We studied the development of first and fourth instars of two lady beetle species ( Coccinella septempunctata L. and Harmonia axyridis Pallas) when provided live or dead weevil larvae versus pea aphids, Acyrthosiphon pisum (Harris). No individuals of either species survived to the second stadium on a diet of weevils (dead or alive), whereas almost 100% of first instars of both species did so on a diet of aphids. Nearly all individuals of H. axyridis that were provided weevils (dead or alive) during the fourth stadium survived and subsequently completed pupation. However, these individuals weighed significantly less as newly molted adults than did conspecifics that had fed on aphids as fourth instars. Only 5% of fourth-instar C. septempunctata survived to adulthood when provided live weevils (versus 100% provided aphids), but 70% did so when provided dead weevils. Both first and fourth instars of both species attacked both dead and live weevil larvae much less readily than aphids, and were often deterred from persisting in the attack by the defensive wriggling of live weevil larvae (in contrast to their persistence and success in attacking aphids). Nevertheless, even first instars of the predators succeeded in some instances in overcoming weevil larvae, and proceeded to feed upon the prey for up to the maximum of 10 min of observation. Our results suggest that although weevil larvae are not very suitable as substitute prey for aphids for the larvae of C. septempunctata and H. axyridis, consumption of weevil larvae especially by older larvae of the predators (particularly H. axyridis) may enable them to complete development in alfalfa fields even when aphid populations fall to low levels.

The hemlock woolly adelgid, Adelges tsugae Annand, is a major threat to hemlocks in the eastern United States. As part of efforts to control this pest, Scymnus ( Neopullus ) sinuanodulus Yu et Yao, a potential predator, was collected from hemlocks in Yunnan, China. Three shipments were imported during 1996 and 1997 to a quarantine laboratory to study the beetle’s biology. Beetles began oviposition immediately after transferal from 5°C in the spring, ceased oviposition by June, and laid the same number of eggs, whether egg laying began in February or in April. Two-year-old beetles laid as many eggs per year as 1-yr-old beetles. We observed only one generation per year. Yearly fecundity averaged 130 eggs with a maximum of 200 per female. Newly emerged beetles remained preovipositional until the following spring, but could be induced to oviposit in the fall by prior exposure to 5 or 10°C for 1.5 mo. The egg, larval (four instars), and pupal stages lasted 10, 20, and 10 d, respectively, at 20°C. From egg to adult took 73, 40, and 35 d at 15, 20, and 25°C, respectively. Larval survival was only 5% at 25°C. Both larvae and adults fed on all stages of A. tsugae, but larvae grew faster with much higher survival on adelgid eggs, and could not complete development on adelgid nymphs alone. When given adelgid eggs, the beetles laid more eggs initially; however, adelgid nymphs seem to satisfy nutritional requirements for oviposition. Laboratory-reared beetles were similar to field-collected beetles in oviposition, fecundity, feeding, survival, and development.

Bioassays were conducted to study the effectiveness of selected chemicals to prevent the multicolored Asian lady beetle, Harmonia axyridis (Pallas), from overwintering in buildings. We discovered that certain monoterpenoids elicited avoidance in adults toward treated filter paper within a petri dish bioassay at 1.0 mg/cm2. Camphor and menthol were the most effective of the monoterpenoids tested. Y-tube olfactometer bioassays revealed that beetles spent significantly more time (within 10-min observation periods) in the untreated control arm than in the arm containing camphor or menthol (both at 100 and 1,000 μg). Another olfactometer bioassay revealed that significantly more beetles remained in the untreated control arm than in the arm containing camphor or menthol (142 μg), within 45-min observation periods. When camphor (9.4% emulsified concentrate) was sprayed onto crevices on the exterior of a building through which beetles were entering, 100% of approaching beetles were repelled for the durat...

Coleomegilla maculata De Geer is an abundant, widely distributed, New World polyphagous lady beetle. High levels of variation at 14 polymorphic allozyme loci were used to examine breeding structure of populations from New England, Iowa, south Texas, and Honduras. Analysis of variance of gene frequencies and F-statistics showed high levels of gene flow within each region and between the Texan and northern United States populations, but negligible rates of gene flow between these and the Honduran populations. Thus, gene flow was largely unrestricted in North American C. maculata. Honduras populations were highly differentiated genetically from the North American populations and shared with North American beetles only 41 of 70 alleles at 14 allozyme loci. Nei’s genetic distances within Honduran, Texas, and Iowa–New England samples did not differ significantly from zero, but the intergroup distances were large. Reciprocal crosses within and between Texas and Iowan populations were fertile, but recipr...

Up to 5 successive inbred generations were produced, through sibling mating, from 64 parental (P) pairs of Propylea quatuordecimpunctata (L.) collected from 3 locations in the northeastern United States. The percentage of P females ovipositing >5 eggs was 62.5% compared with a mean of 43% for inbred generations F1 to F4. The percentage of intercross (F2 to F4) females producing >5 eggs was 61 ± 16% (mean ± SE), showing a restoration of fecundity. Egg hatch decreased from 84 ± 9% in the P to 4 ± 7% in the F4. Preimaginal developmental time among inbreds increased from 17 d in the F1 to >19 d in the F4. First instar to adult survivorship among inbreds decreased from 96.6 ± 0.9% in the F1 to 37.6 ± 3.7% in the F4. In contrast to the inbreds, mean survivorship in the intercross generations was 85 ± 11%, showing a restoration of viability. No effect of inbreeding on body size was detected. The high sensitivity to inbreeding in P. quatuordecimpunctata probably is caused by a high frequency of partially recessive deleterious alleles and overdominant loci.

Aphidophagous lady beetles feed on a variety of prey in addition to preferred aphids. These alternative foods may serve only to maintain the predator but do not permit immature growth or adult reproduction. We tested whether larvae of the alfalfa weevil, Hypera postica (Gyllenhal), are alternative foods for adults of 2 species of lady beetles, Coccinella septempunctata L. and C. transoersoguttata Brown, that breed in alfalfa while feeding on the larvae as well as aphids. When collected from alfalfa fields and placed on diets of weevils only, adults of both species generally gained weight. However, in contrast to females fed pea aphids, Acyrthosiphon pisum (Harris), females fed weevils produced very few eggs, almost all of which were laid in the first few days after the predators were placed on the weevil diet. When dissected, females fed weevils had only very small (previtellogenic) eggs in their ovaries. Similarly, females produced very few eggs, and held only previtellogenic eggs of very small size in their ovaries, when provided only sucrose (dissolved in water in 15% solution). When provided both weevils and sucrose, however, females of both species laid eggs in modest numbers. These results indicate that weevil larvae serve as alternative foods for the lady beetles, and that reproduction nevertheless can occur in the absence of preferred aphid prey when weevil larvae are combined in the diet with sucrose, another alternative food. Because nectar can serve as a natural source of sucrose in or near alfalfa fields, some reproduction by lady beetles may occur in fields infested with weevil larvae even in the absence or low abundance of aphids.

Predator consumption, development, and fecundity were assessed for the predatorprey interaction between Coleomegilla maculata (De Geer) and Leptinotarsa decemlineata (Say) feeding on Cry3A-transgenic or normal (nontransgenic) foliage of potato. The influence of bee pollen, a food supplement, on development and fecundity was also assessed. Neonates of L. decemlineata feeding on transgenic foliage lost considerable body weight, in comparison to those feeding on normal foliage. After differences in prey weight were considered, no significant difference was found between the proportion of transgenic-fed or normal-fed neonates consumed by C. maculata . There was no significant difference between the proportion of C. maculata developing into pupae and adults when reared on transgenic-fed or normal-fed prey; nor did the live weight of teneral adults differ. The proportion of C. maculata reaching maturation when reared on transgenic-fed prey with pollen was greater than those reared on pollen alone, which suggests the suitability of a diet containing animal and plant material. Predator fecundity, measured as egg deposition per day, was not significantly different between mated females provided with transgenic-fed prey with pollen or normal-fed prey with pollen. These data suggest that Cry3A-intoxicated L. decemlineata can be eaten by C. maculata without any observable adverse effects on their survival or predation potential.

Nephaspis oculatus (Blatchley) is a common introduced coccinellid predator in Florida, which feeds on many whitefly species. We evaluated development, consumption rates, survivorship, longevity, and fecundity of a southern Florida (Immokalee) population of this coccinellid on a diet of eggs of Bemisia argentifolii Bellows & Perring. Developmental time was 4.6, 3.3, 1.5, 1.5, 3.0, and 5.2 d for eggs, 1st, 2nd, 3rd, 4th instars, and pupae, respectively, with an average of 19.4 d from oviposition to adult emergence for females and 18.3 d for males. Daily consumption of whitefly eggs by male and female larvae was not significantly different (average 79 for males, and 86 for females) with a mean of 16, 68, 128, and 124 eggs consumed per larva per day by 1st, 2nd, 3rd, and 4th instars, respectively, totaling 51, 132, 192, and 373 eggs for each successive larval stage. Male-female pairs of adults consumed a mean of 184.1 eggs per day over a period of 16 wk. Adult females from a 2nd population in central Florida (Apopka) consumed an average of 78.0 B. argentifolii eggs per day over a period of5 wk, and males consumed 123.0 eggs per day. The sex ratio of 1,153 beetles was 1.00:0.89 female to male. Adult longevities averaged 56.1 d for males, and 67.5 d for females. After an average 11.3-d preoviposition period, females laid a mean of 3.03 eggs per day. Net reproductive rate was estimated by life table analysis at 54.27, generation time was 51.27 d, and doubling time was 8.89 d. Intrinsic rate of population increase was estimated at 0.078, or A = 1.08 for finite rate of increase. N. oculatus showed good potential for biological control of B. argentifolii, especially in greenhouses.

Pseudoscymnus tsugae sp. nov. is described. In Honshu, Japan, it has been collected between 34°11' and 36°50'N latitude and from sea level to 1,980 m. The adult and the mature larva are illustrated. The beetle may be a good candidate for the biological control of hemlock woolly adelgid, Adelges tsugae Annand, in North America.

Adults of the introduced coccinellid Harmonia axyridis (Pallas) were collected at aggregation sites in the autumn of 1993 and 1994 and described in terms of sex, size, and phenotype. Mating status and ovariole numbers of females and parasitism rates of both sexes were obtained by dissection. Females were larger than males, and beetles of both sexes from high elevations were larger and darker than their counterparts from lower elevations. In 1993, 11.8% of females had sperm in their spermathecae but 41.4% of females were mated in 1994. Adults were parasitized by Strongygaster triangulifera (Loew) (Tachinidae) at rates of 14.2 and 1.4% in 1993 and 1994, respectively.

High levels of genetic variation in biological control agents are thought to be necessary to ensure their successful establishment and geographical spread. Gene diversity was studied in F2 twospotted lady beetle, Adalia bipunctata (L.), descended from specimens collected in Uzbekistan and from beetles collected in Oregon, Iowa, and Lake Michigan at Chicago, IL. Twenty-four of 39 resolved putative loci were polymorphic and the mean observed heterozygosity was 22.7 ± 4.4% at the polymorphic loci. The average expected heterozygosity was 24.7 ± 4.9% at the polymorphic loci and 15.2 ± 3.3% at all loci. The mean number of alleles at the 39 loci was 1.9 ± 1.0, and the mean effective number of alleles was 1.3 ± 0.5. These are substantial levels of diversity. Significant departures from random mating were detected within ( FIS = 0.068 ± 0.042) and among ( FST = 0.070 ± 0.012) the North American populations but matings were random within populations when problematic loci were excluded. Analysis of gene frequencies at 5 loci in 4 British and a French population showed the same magnitude of gene flow as the 3 North American populations. The fixation index between Iowa and Uzbekistan ladybirds was FST = 0.428 ± 0.128. Our data do not support an Old World origin for North American A. bipunctata in historical times.

The influence of temperature on the development rate and expression of 3 elytral color patterns in the lady beetle, Calvia quatuordecimguttata (L.), was assessed at 6 constant temperatures between 10 and 34°C. The expression of the 3 elytral color patterns was discrete and independent of temperature treatment. No differences were observed among the color morphs in the real or physiological time for egg-to-adult development, or for pupal weight. However, temperature did influence survival and growth rates of the overall population. No eggs hatched at 34°C. Larval mortality was high at 10°C and moderate between 14 and 30°C. Development time from oviposition to adult was 14.6 ± 0.9 d at 30°c and 95.6 ± 9.0 d at 10°C. The total heat-unit requirement for egg to adult development was 274.1 DD above a mean development-threshold of 8.2°C. Pupal weight differed among temperature treatments and was greatest at 10-22°C, and lowest at 26 and 30°C.

We compared the morphological characteristics of the scale covers and bodies of 2 economically important scale species, California red scale, Aonidiella aurantii (Maskell), and oleander scale, Aspidiotus nerii (Bouche), to determine their protective value against predation by the coccinellid Rhyzobius lophanthae (Blaisdell). We also compared the morphology of the mandibles of R. lophanthae with that of Chilocorus cacti (L.), a specific predator of diaspidid scales. A higher percentage of R. lophanthae larvae survived when they fed on 2nd- and 3rd-instar A. aurantii and all stages of A. nerii than when they fed on gravid and parturient A. aurantii . Adult R. lophanthae took longer to consume 3rd-instar A. aurantii than 3rd-instar A. nerii and were frequently unable to penetrate the scale body of gravid and parturient A. aurantii . Predator preference for scale stage and species reflected the ease with which it was able to penetrate the scale cover and body of its prey. The hardened scale cover of gravid and parturient A. aurantii when coupled with the sclerotized scale body provided the scale with substantial immunity to predation by R. lophanthae for approximately two-thirds of the scale life span. We conclude that R. lophanthae is unlikely to suppress A. aurantii populations below those of economic concern when it is the sole biological control agent present. In contrast, the entire life span of A. nerii is vulnerable to predation, and this species appears to be suppressed to low densities by R. lophanthae .

Dinocampus coccinellae (Schrank) spent >80% of a 300-s observation period in host-handling activities (orienting toward, pursuing, and attacking hosts) when exposed to individual adult Coleomegilla maculata (DeGeer) or Coccinella septempunctata (L.). When D. coccinellae was exposed to two populations of Hippodamia variegata (Goeze) from Canada or France and Propylea quatuordecimpunctata (L.) from Canada or Turkey, host-handling activities decreased to

Development, survival, and reproduction of Scymnus frontalis (F.) were stud ied in the laboratory at four temperature regimes with means ranging from 15 to 30°C, with daily fluctuations of ±5°C. S. frontalis has four instars and a distinct prepupal stage. Developmental times from egg to adult averaged 79.7, 45.3, 21.4, and 17.2 d at mean temperatures of 15, 18.7, 26.2, and 30°C, respectively. Calculated stage-specific developmental thresholds ranged from 10.1°C for first instars to 13.0°C for fourth instars. Development from egg to adult required an average of 312.2 degree-days above a base of 11.7°C. Survival was highest at the two intermediate temperatures and lowest at a mean temperature of 15°C with mortality being highest in eggs and first instars. Preoviposition periods ranged from 20.5 d at a mean temperature of 15°C to 7.7 d at 30°C. Daily oviposition rates per female during the first several weeks of reproductive life were highest at a mean temperature of 26.2°C (7.25 eggs per female per day). The proportion of females ovipositing was highest at 26.2°C (0.97) and lowest at 15°C (0,42). Compared with its prey, Diuraphis noxia (Mordvilko), the Russian wheat aphid, S. frontalis requires higher temperatures to complete development and reproduce.