The paper, ‘Life Table Studies of Elasmopalpus lignosellus (Lepidoptera: Pyralidae) on Sugarcane,’ by Hardev S. Sandhu, Gregg S. Nuessly, Susan E. Webb, Ronald H. Cherry, and Robert A. Gilbert, Environmental Entomology (2010) 39(6): 2025–2032, is withdrawn at the request of the authors due to numerous errors that cannot readily be corrected by publishing an erratum. I acknowledge the valuable input of Prof. Hsin Chi, Department of Entomology, National Chung Hsing University, Taichung, Taiwan, in raising significant questions about the published paper. — E. Alan Cameron, Editor-in-Chief

Agricultural intensification in western Europe has caused a dramatic loss of grassland surfaces in farmlands, which have resulted in strong declines in grassland invertebrates, leading to cascade effects at higher trophic levels among consumers of invertebrates. Grasshoppers are important components of grassland invertebrate assemblages in European agricultural ecosystems, particularly as prey for bird species. Understanding how grasshopper populations are distributed in fragmented landscapes with low grassland availability is critical for both studies in biodiversity conservation and insect management. We assessed the range and strength of spatial autocorrelation for two grasshopper taxa (Gomphocerinae subfamily and Calliptamus italicus L.) across an intensive farmland in western France. Data from surveys carried out over 8 yr in 1,715 grassland fields were analyzed using geostatistics. Weak spatial patterns were observed at small spatial scales, suggesting important local effects of management practices on grasshopper densities. Spatial autocorrelation patterns for both grasshopper taxa were only detected at intermediate scales. For Gomphocerinae, the range of spatial autocorrelation varied from 802 to 2,613 m according to the year, depending both on grasshopper density and on grassland surfaces in the study site, whereas spatial patterns for the Italian locust were more variable and not related to grasshopper density or grassland surfaces. Spatial patterns in the distribution of Gomphocerinae supported our hypothesis that habitat availability was a major driver of grasshopper distribution in the landscape, and suggested it was related to density-dependent processes such as dispersal.

Freshwater ecosystems are positioned at low levels in the landscape and receive large inputs of diverse plant-based detritus, a major source of energy for consumers in aquatic ecosystems. We conducted field experiments in Urbana, IL to determine the independent and combined effects of leaves of common tree species including the northern red oak (Quercus rubraL.), sugar maple (Acer saccharum Marshall), and common hackberry (Celtis occidentalis L.) on the performance of containerdwelling mosquitoes, especially Culex restuans Theobald (Diptera: Culicidae). We tested the hypothesis that leaf species have asymmetric effects on adult mosquito production and longevity. Hackberry followed by combined leaf treatments and maple produced the greatest number of pupae, whereas oak leaves produced the fewest. Leaf treatments had no significant effects on adult female sizes but female longevity was significantly lower in oak leaf treatments compared with the other leaf treatments. These findings support the hypothesis that leaf species identity influences the performance of container-dwelling mosquitoes with potential consequences for the transmission of infectious diseases.

Ground beetles (Coleoptera: Carabidae) are a major component of terrestrial invertebrate communities and have been used as bioindicators of habitat change and disturbance. The Black Hills of South Dakota is a small area with a high biodiversity, but the ground beetles of this region are little studied. The habitat preferences of ground beetles in the Black Hills are unknown, and baseline data must be collected if these beetles are to be used in the future as bioindicators. Ground beetles (Coleoptera: Carabidae) were collected from pitfall traps at two sites in each of five kinds of habitats (grassland, bur oak—ironwood forests, ponderosa pine—common juniper forests, aspen—pine forests, and a spruce forest) from which habitat structure characteristics and plant abundance data also were collected. In total, 27 species of ground beetles were identified. Although some species, such as Dicaelus sculptilis Say were found in most habitats, other species showed distinct habitat preferences: Poecilus lucublandus (Say) preferred oak forests, Pasimachus elongatus LeConte preferred grasslands, and Calathus ingratus Dejean preferred high-elevation aspen—pine forests. Pterostichus adstrictus Escholtz was found only in woodlands, and Carabus taedatus Say strictly in higher elevation (over 1,500 m) aspen or coniferous woods, and may represent relict populations of boreal species. Elevation, exposure to sunlight, and cover of woody plants strongly influence the structure of carabid communities in the Black Hills.

The role biodiversity plays in the provision of ecosystem services is widely recognized, yet few ecological studies have identified characteristics of natural systems that support and maintain ecosystem services. The purpose of this study was to identify landscape variables correlated with natural pest suppression carried out by arthropod natural enemies, predators and parasitoids. We conducted two field experiments, one observational and one experimental, where landscape variables at broad and local scales were measured and related to natural pest suppression. The first experiment measured natural pest suppression at 16 sites across an urban to rural landscape gradient in south central Wisconsin. We found natural enemy diversity positively affected natural pest suppression, whereas flower diversity negatively affected pest suppression. No relationship was found between natural pest suppression and broad scale variables, which measured the percentage of different land cover classes in the surrounding landscape. In the second experiment, we established small (2- by 3-m ) replicated plots that experimentally varied flower diversity (0, 1, or 7 species) within a plot. We found no significant relationship between natural pest suppression and the different levels of flower diversity. The fact that we only found differences in natural pest suppression in our first experiment, which measured natural pest suppression at sites separated by larger distances than our second experiment, suggests the more appropriate scale for measuring ecosystem services performed by mobile organisms like insects, is across broad spatial scales where variation in natural enemies communities and the factors that affect them become more apparent.

A combination of observational and experimental methods, in both the laboratory and field, were used to assess niche partitioning between Ceutorhynchus alliariae Brisout and C. roberti Gyllenhal (Coleoptera: Curculionidae), two coexisting shoot-boring weevils on garlic mustard, Alliaria petiolata (M. Bieb.) Cavara and Grande (Brassicaceae). We compared their morphology, oviposition behavior, larval development, distribution, abundance, and attack rates in their sympatric range, and of C. alliariae when found alone and in sympatry with C. roberti. Results indicate only very small differences in the fundamental niches of the two species. Comparison of C. alliariae in the range it occurs alone with the range where it co-occurs with C. roberti revealed some evidence for competition between the two species, i.e., attack levels of C. alliariae were reduced in areas where it co-occurred with C. roberti. However, the study showed no character displacement in regard to adult size or shoot choice of C. alliariae and we found no indication for superiority of either of the two species. Clearly, manipulative experiments would be necessary to unambiguously test for competition between the two species. Our results, based on a subset of niche dimensions known to be important in other systems, suggest that C. alliariae and C. roberti may present one of the rare cases, in which niche differentiation is not the main mechanism underlying coexistence.

Biological control of insects by predators may be indirectly influenced by management practices that change the invertebrate community in agroecosystems. In this study we examined effects that mulching and weeding have on predatory beetles (Carabidae and Staphylinidae) and their potential prey in a highbush blueberry field. We compared beetle communities in unweeded control plots to those that were weeded and / or received a single application of compost or pine needle mulch. Compost mulch and weeding significantly affected the carabid community while the staphylinid community responded to compost and pine needle mulches. Effects because of mulch tended to intensify in the year after mulch application for both families. Estimates of species richness and diversity for Carabidae and Staphylinidae were similar in all plot types, but rarefaction curves suggested higher Carabidae richness in unmulched plots despite fewer individuals captured. Carnivorous Carabidae, dominated by Pterostichus melanarius, were most frequently captured in compost plots both years, and omnivores were most frequently captured in unweeded compost. Density of millipedes, the most abundant potential prey, was generally greater in mulched plots, whereas seasonal abundance of small earthworms varied among mulch types. Our results have potential implications for biological control in mulched highbush blueberries depending on beetle consumption rates for key pests and how rates are affected by alternative prey.

Phoridae (Diptera) have widespread impacts on insect communities by limiting host ant behavior. However, phorid—ant interactions may vary with habitat or environmental conditions. Three Pseudacteon species parasitize Azteca instabilis Fr. Smith, a common ant in coffee agroecosystems, and limit A. instabilis foraging, indirectly benefiting other insects. However, little is known about how phorid abundance, behavior, and effects change with environmental conditions. In shaded coffee systems, coffee (Coffea arabica L. ) grows under a range of shade conditions and management changes affect species interactions. For example, Pseudacteon spp. more strongly limit A. instabilis foraging in low-shade coffee habitats. We sampled relative abundance of three phorid species around A. instabilis nests in three coffee habitats varying in shade management during dry and wet seasons. We measured canopy cover, tree richness, tree density, leaf litter depth, and number of nearby trees with A. instabilis to determine whether these habitat factors correlate with phorid abundance. P. laciniosus Brown was the most abundant phorid in both seasons. Phorid relative abundance did not differ by habitat, but did differ by season. P. laciniosus accounted for a higher proportion of phorids in the wet season (91.4%) than in the dry season (78.9%), and P. planidorsalis Brown accounted for a larger percent in the dry season (21.1%) than in the wet season (7.3%). Phorid composition did not differ with habitat type, and none of the measured environmental variables correlated with changes in phorid composition. Thus, phorids in coffee agroecosystems respond to large seasonal differences, but not differences between coffee habitats.

The fungal entomopathogen Entomophaga maimaiga has provided important biological control of gypsy moth, Lymantria dispar (L.), since the first epizootics occurred in the northeastern United States in 1989. Epizootics are initiated by germination of soil-borne resting spores, which are highly sensitive to spring temperature and moisture. We compared gypsy moth infection by E. maimaiga in 33 oak stands in Michigan with infection under optimal laboratory conditions from 1999 to 2001 to assess differences between potential and realized efficacy of E. maimaiga. Field bioassays were conducted by exposing laboratory-reared, fourth-instar gypsy moth to soil at the base of oak trees for 4 d. Additional larvae were similarly exposed to soil collected from the field plots in laboratory bioassays with temperature, humidity, and moisture levels optimal for fungal germination. Overall E. maimaiga infection ranged from means of 3.2–29.8% in the field compared with 20.9–59.7% in the laboratory during three field seasons. Resting spore density in soil and gypsy moth egg mass density were significant predictors of field infections in two of the 3 yr, whereas resting spore density was a significant predictor of laboratory infections each year. Other variables that significantly predicted laboratory infections in one of the 3 yr included egg mass density, canopy cover, and soil pH. In laboratory bioassays, soil pH and E. maimaiga resting spore density were positively associated with increasing E. maimaiga infection rates of gypsy moth larvae.

The suitability of tomato leaves of different ages for Bemisia tabaci (Gennadius) B biotype and Trialeurodes vaporariorum (Westwood) was characterized by development time, stage-specific survival, sex ratio, longevity, and fecundity. Three categories of leaf ages were tested (young: expanding leaves <2 wk old; mature: fully expanded, 4–5-wk-old leaves; old: fully expanded, 6–7-wk-old leaves). There was no significant variation in the duration of development of the two species among the three classes of leaf ages, but total survival and ratio of females to males on mature and old leaves were higher than on young leaves. For egg hatch, the reverse tendency was found. Longevity of both species was higher on mature than on young leaves, and fecundity during the first 2 wk of adult life was higher on mature than on young or old leaves. The B. tabaci B biotype developed faster through the quiescent fourth nymphal instar, had higher ratio of females to males, survived longer, and produced more eggs (in the first 2 wk of adult life) than T. vaporariorum on leaves of the same age; although on young leaves, B. tabaci B biotype survivorship was lower than that of T. vaporariorum. The index of host suitability of B. tabaci B biotype was higher on mature and old leaves than on young leaves. In T. vaporariorum, no such differences were found among these three leaf ages. The results could provide some cues why B. tabaci B biotype is spreading so vigorously.

Larvae of 11 species of picture-winged flies (Diptera: Ulididae) are known to feed on corn plants (Zea mays L. ) in the western hemisphere. Larvae emerge from eggs deposited in leaf axils and corn silk to feed mostly within ears, but the primary versus secondary nature (i.e., pest status) of their infestation is not known for all of these species. Choice and no-choice tests by using a split-plot design were conducted in greenhouse and field trials to determine the pest status on sweet corn of three of these species found in Florida: Chaetopsis massyla (Walker), Euxesta eluta Loew, and E. stigmatias Loew. The main treatments (uninfested ears and ears experimentally infested with either Spodoptera frugiperda [Lepidoptera: Noctuidae] or E. eluta larvae) were applied at first silk. The subtreatments (C. massyla, E. eluta, or E. stigmatias adults caged on ears) were applied 7 d later and maintained for 10 d. All three fly species were reared from uninfested and experimentally infested ears in both choice and no-choice tests in greenhouse and field trials confirming both primary and secondary modes of ear infestation. More flies of all three species emerged from ears that were preinfested with S. frugiperda compared with uninfested ears suggesting either preference for or greater survival within ears previously infested by S. frugiperda. Fewer E. eluta and E. stigmatias emerged from ears preinfested with E. eluta in no-choice field tests, suggesting that previous infestation by this fly may negatively affect oviposition or that older fly larvae affect survival of neonate larvae. All three species studied here should be considered primary pests that can render unprotected sweet corn ears unmarketable.

The severity of damage to host plants by omnivorous pests can vary according to the availability of plant and animal prey. Two omnivorous mole crickets, Scapteriscus vicinus Scudder and S. borellii Giglio-Tos, were used to determine if the availability of prey influences damage to hybrid bermudagrass by adult mole crickets. Experiments were conducted in arenas with either grass alone (control), grass plus one mole cricket, grass plus earthworms (Eisenia fetida Savigny), or grass with earthworms and a mole cricket. Root growth variables (e.g., volume, dry weight) after 4 wk and weekly measurements of top growth were compared among the treatments. Surprisingly, bermudagrass infested with either mole cricket species caused no significant reduction in root growth and a minimal reduction on top growth with S. vicinus compared with controls. Survival of earthworms with S. borellii was significantly lower than survival in the earthworm-only treatment suggesting predation. Survival of earthworms with S. vicinus, however, was not different from the earthworm-only treatment. The addition of earthworm prey with mole crickets did not significantly impact bermudagrass root or shoot growth relative to grass with only mole crickets. Despite no negative impacts from earthworms or mole crickets separately, earthworms plus mole crickets negatively impact several root parameters (e.g., length) suggesting an interaction between these two soil-dwelling invertebrates. Increased use of more target-selective insecticides in turfgrass may increase available prey. This work suggests that alternative prey, when present, may result in a negative impact on turfgrass roots from foraging omnivorous mole crickets.

Over 60 Pieris taxa (Ericaceae) were measured for their susceptibility to the Andromeda lace bug, Stephanitis takeyai Drake and Maa, and the azalea lace bug, Stephanitis pyrioides (Scott) (Hemiptera: Tingidae) based on leaf damage, adult survival on leaves, and emergence of nymphs in no-choice petri dish assays. Pieris phillyreifolia (Hook. ) DC. and P. japonica (Thunb. ) D.Don ex G.Don ‘Variegata’ were consistently resistant to both species of lace bugs, whereas P. japonica ‘Cavatine’ was consistently susceptible to both. Pieris japonica ‘Temple Bells’ was highly susceptible to S. takeyai, but resistant to S. pyrioides. Nymph emergence was noted only with S. takeyai, on 46 Pieris taxa, whereas S. pyrioides nymphs were not observed on any of the Pieris taxa. Choice assays (with 10 Pieris taxa) and whole plant assays (with five Pieris taxa) using S. takeyai alone also were conducted, confirming the resistance of P. phillyreifolia and susceptibility of P. japonica Temple Bells to lace bug feeding.

This study examines some of the potential mechanisms of resistance in selected Pieris (Ericaceae) taxa to the Andromeda lace bug, Stephanitis takeyai Drake and Maa, based on differences in resistance to lace bug feeding, and the possible role of leaf parameters such as leaf wax, toughness, nutrient composition, and stomatal characters in plant resistance. Experiments with extracts of leaf-surface lipids revealed that Pieris leaf wax did not have a role in resistance to lace bug feeding. Leaf wax extracts from a resistant species P. phillyreifolia (Hook.) DC. applied to leaves of a susceptible cultivar P. japonica (Thunb.) D.Don ex G.Don ‘Temple Bells’ did not affect feeding, oviposition, or survival of S. takeyai; and neither the extracts from Temple Bells induce susceptibility in P. phillyreifolia. Leaf penetrometer measurements indicated that significantly higher force was required to puncture P. phillyreifolia leaves, which also had higher fiber, lignin, and cellulose, and lower leaf moisture contents. Ultrastructural examination of leaves of Pieris taxa revealed significant differences in the number and size of stomata. P. phillyreifolia leaves had the highest number of stomata per unit area but these were the smallest in size, whereas P. japonica (Thunb.) D.Don ex G.Don Temple Bells leaves had the fewest and largest stomata. Resistance in Pieris taxa to S. takeyai may be attributed to a combination of different factors including leaf toughness, moisture, and stomatal characters. The type of resistance may be described as antixenosis combined with antibiosis, because reduced adult survival and reproduction were observed on the taxa resistant to lace bug feeding.

Ants are the most abundant visitors to the flowers of Jatropha curcas L., but it is not clear how much they contribute to the pollination of this plant. In this study, we observed floral visitor assemblage and foraging behavior of ants, measured pollen loads carried by ants and deposited on stigmas, and determined the contribution of ants to the female reproductive success of J. curcas through exclusion experiments. Ants were the most abundant pollinators, accounting for 71.03 and 78.17% of total visits at two study sites. Among different ant species, Tapinoma melanocephalum (F.) is always the most abundant and the only common ant species at two study sites, which might suggest its important role in the pollination of J. curcas. Pollen loads carried by ants were significantly different among different species at two study sites. Pollen loads carried by ants increased with increased body length. Although the flowers exposed only to the ants produced less fruit than those exposed only to the winged visitors, ants alone resulted in almost 60% fruit set. Thus, ants could play a major role in the pollination of J. curcas if winged insects are absent.

The introduced biological control agent Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) has attained pest status in North America as its presence in vineyards during harvest may compromise the quality of the resulting wine. Control of H. axyridis in vineyards is difficult as their populations may fluctuate daily, and there are few products registered to control this pest. Sulfur dioxide, in the form of potassium metabisulfite (KMS), is commonly used in wine as both an antimicrobial and an antioxidant. In this study, the effectiveness of KMS as a repellent against H. axyridis was measured. In a Y-tube olfactometer, H. axyridis spent significantly less time in the treatment arm (KMS 2.5, 5, and 10 g/liter) than in the control arm during a 10-min period. When sprayed in a vineyard, KMS significantly reduced the number of H. axyridis on grape vines. KMS is an effective repellent against H. axyridis and may be suitable for use in vineyards to control this pest. KMS (5 g/liter) applied to Riesling grapes at 2 wk, 1 wk, 3 d, or 1 d before harvest did not affect free sulfur dioxide in either freshly processed or settled juice. This study lays the foundation for the development of a pest management strategy incorporating repellents for H. axyridis in vineyards.

The mobility of olive fruit fly, Bactrocera oleae (Rossi), late third instars before pupation, teneral adults before flight, and mature adults restricted from flight were studied under mulches in greenhouse cage tests, in horizontal pipes, vertical bottles and pipes filled with sand, and by observation on smooth laboratory surfaces. Percentage adults emerging from pupae and percentage adult females that escaped soil, fabric, and paper mulches over a soil or sand substrate ranged from 63 to 83, and 40–53%, respectively. Percentage adults emerging from pupae and percentage adult females that walked through the open interior of 1.52–6.10-m horizontal pipes of 1.5–2.0-cm inner diameter ranged from 57 to 81, and 27–61%, respectively. Percentage adults emerging from pupae that escaped through sand depths of 2.5–10.2, and 12.7–20.3 cm, ranged from 68 to 87, and 12–88%; and percentage adult females that escaped ranged from 46 to 58, and 38–70%, respectively. In 15.4-cm-inner-diameter pipes filled with different heights of sand, the highest percentage of the total number of adults that emerged in the control were found from 0 to 20.3 cm, and ranged from 37 to 71%. Ten to 47% of adults were found from 20.3 cm to below the surface, and 6–21% escaped to the top of 20.3–50.8 cm high sand columns. In column heights of 55.9 and 61 cm, pressures at the bottom caused by the weight of the sand above were 91.4 and 99.7 g/cm², respectively, and a mean of <1 adult escaped to the top. Before pupation, the late third instars were found to travel continuously for 6.9 h over 23.9 m at a speed of 6.0 cm per min, when placed on a smooth surface, at 22.2°C. Teneral females and males that could not fly, made ≈7 stops totaling 11–13 min, walked at a speed of 57–62 cm per min, and began a rest period of 83–84 min duration, at 85–89 min before flight. Males walked a distance of 13.1 m in 22 min, which was greater than females that walked for 9.6 m in 17 min, at 20–22°C and 35% RH. The mobility of the third instars and the teneral adults is discussed in relation to potential control techniques in olive orchards.

Developmental time, longevity, and lifetime fertility of three previously introduced parasitoids (Acerophagus papayae Noyes and Schauff, Anagyrus loecki Noyes and Menezes, and Pseudleptomastix mexicana Noyes and Schauff) (Hymenoptera: Encyrtidae) of the mealybug Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) were studied in the laboratory to understand the outcome of their recovery in field studies conducted in the United States. The developmental time of both male and female A. papayae and A. loecki was shorter than the developmental time of male and female P. mexicana. Male parasitoids of all three species had a shorter developmental time than their females. All parasitoids had a shorter developmental time in adultfemale mealybugs than in second instars. Mating status (unmated and mated) had no effect on the male longevity. Unmated and mated females that were not allowed to oviposit had similar longevity and lived longer than those that were allowed to oviposit. Virgin females produced male only progeny with higher number of males from A. loecki or P. mexicana than from A. papayae. The number of females and the cumulative progeny was smaller for A. papayae than for A. loecki or P. mexicana. The progeny sex ratio (proportion of females) was not different among the parasitoids. A. papayae had the shortest reproductive period followed by A. loecki and P. mexicana, respectively. This information is important in evaluating the efficiency, recovery and establishment of A. papayae, A. loecki, and P. mexicana.

The temperature-dependent development of tomato psyllid (also called potato psyllid), Bactericera cockerelli (Sulc), was studied in the laboratory at seven constant temperatures (8, 10, 15, 20, 23, 27, and 31°C), 50–60% RH, and a photoperiod of 16:8 (L:D) h on leaves of whole potato (Solanum tuberosum L.) and tomato (Solanum lycopersicum L.) plants. Developmental time in days for immature stages and total development (egg to adult) on both host species were inversely proportional to temperature between 8 and 27°C but increased at 31°C One linear and two nonlinear models were fitted to the data. The lower developmental thresholds, calculated using the linear model for egg, total nymph, and total development (from oviposition to adult emergence) were 7.9, 4.2, and 7.1°C (reared on potato) and 7.2,5.3, and 7.5°C (reared on tomato), respectively. The thermal constant (K) for total development was 358 (reared on potato), and 368 (reared on tomato) degree-days (DD). Two nonlinear models, Briere and Lactin, fit the data well as measured by goodness-of-fit criteria, the residual sum of square (RSS) and Akaike information criterion (AIC). Temperature threshold parameters for these nonlinear models (T₀, T_opt, and T_max) were estimated for eggs, total nymphal stages, and total development time (egg to adult). The Briere model is highly recommended for the description of temperature-dependent development of tomato psyllid. Results from this study will provide basic information on the biology of tomato psyllid and have potential for the development of predictive models of the seasonal progress of this invasive pest.

The beet webworm, Loxostege sticticalis (L.) (Lepidoptera: Pyralidae), uses both diapause and migration as life history strategies. To determine the role of diapause plays in the population dynamics of L. sticticalis, the reproductive and flight potentials of adults originating from diapause and nondiapause larvae were investigated under controlled laboratory conditions. Preoviposition period, lifetime fecundity, and daily egg production of females originating from diapause larvae were not significantly different from those originating from nondiapause larvae, showing that diapause has no significant effect on reproductive capacity when adults are provided with an adequate carbohydrate source. However, females that developed from diapause larvae lived significantly longer than those from nondiapause larvae. Flight capacity, including flight duration, distance and velocity of 3-d-old adults were all significantly greater in adults originating from diapause larvae than those from nondiapause larvae. L. sticticalis adults developing from diapause larvae tended to have more extreme values of longest flight duration and furthest flight distance than those from nondiapause larvae. Together, these results suggest that long-distance flight potential of L. sticticalis is greater after larval diapause than after direct development to adulthood. However, there were no significant differences between sexes within the two categories of moths in terms of total flight duration, total flight distance, flight velocity, and longest flight duration.

The life history of Brontispa longissima (Gestro) (Coleoptera: Hispidae), reared under laboratory conditions on leaves of coconut (Cocos nucifera L.), royal palm [Roystonea regia (Kunth) O.F.Cook], bottle palm [Hyophorbe lagenicaulis (L. Bailey) H.E.Moore], and fishtail palm (Caryota ochlandra Hance) was analyzed using age-stage, two-sex life table. Means and standard errors of population growth parameters were calculated using the jackknife method. Moreover, survival rate and fecundity data were applied to project the population for revealing the different stage structure. The mean intrinsic rates of population growth when reared on each respective leaf type were 0.032, 0.031, 0.019, and 0.044. Individuals reared on C. nucifera achieved the highest net reproduction rate at 114.5 offspring per female. The mean generation times of B. longissima ranged from 93.2 d (reared on C. ochlandrai) to 161.5 d (reared on H. lagenicaulis). Projections from survival rate and fecundity data indicated that B. longissima populations can row considerably faster on C. ochlandra than on the other three host plants. The results validate the two-stage life history approach taken, providing an essential tool for developing and testing future control strategies.

Effects of ambient spring air temperature and light intensity on stylet penetration activities of the glassy-winged sharpshooter, Homalodisca vitripennis (Germar), were studied under field conditions by using an electrical penetration graph. Electrical penetration graph waveforms representing salivary sheath formation and searching (pathway phase),xylem contact (X waves), and ingestion of xylem fluid (waveform C) were analyzed. Previous research supported the concept that acquisition of Xylella fastidiosa, the Pierce's disease bacterium, occurs during ingestion, whereas inoculation occurs during xylem contact periods (X waves). Diel patterns of H. vitripennis stylet activity showed that, regardless of light condition, xylem ingestion occurred for the longest duration when temperature remained above the feeding threshold (10°C), and only occurred at temperatures below the threshold when ingestion was continued from a preceding, warmer time. Regression analysis indicated that mean waveform durations per insect (WDI) for combined stylet activities (pathway and ingestion) as well as X wave frequencies were significantly influenced by temperature, but there was no significant impact of light intensity or interaction between temperature and light intensity. The relationship between temperature and stylet activities in terms of WDI and X wave frequency was described using linear and nonlinear models. Validation of the nonlinear models indicated that they well predicted the WDIs for both ingestion and combined stylet activities, using temperature only as a single input. Overall, findings clearly demonstrate that temperature is an important factor that influences the H. vitripennis feeding behaviors responsible for transmission (acquisition and inoculation) of the Pierce's disease bacterium, with implications for vector ecology and management, as well as disease epidemiology.

The planthopper, Nilaparvata lugens Stål (Homoptera: Delphacidae), uses acoustic signals generated by abdominal vibration and transmitted through rice (Oryza sativa L.) plants to locate mates. The influence of temperature (20, 28, and 32°C) on abdominal vibration patterns of individual females and males, proportion of mated females, and responsivity of male to female vibrational signals was investigated. When female and male adults were observed individually, temperatures of 20 and 32°C inhibited abdominal vibration by both genders in terms of proportion of vibrating insects, time spent in vibration per insect, time spent per bout of vibration, or all of these; the effects were more pronounced at 32°C than at 20°C especially in males at 32°C. Although not significantly different, male responsivity to vibrating female was relatively high at 28°C, lower at 32°C, and still lower at 20°C, and finally more males located females at 28°C than at 20°C, which contributes to the higher proportion of mated females at 28°C than at 20 or 32°C. Our results indicate that temperatures of 20 and 32°C inhibit the production of abdominal vibration and, to some extent, reduce male responsivity to female vibrational signals, which may partially explain the frequent population outbreaks in N. lugens in the years with warm autumn.

Rapid, accurate, and timely identification of insects as a group is important and challenging worldwide, as they outnumber all other animals in number and diversity. DNA barcoding is a method for the identification of species in a wide range of animal taxa, which uses the 5′ region of the mitochondrial cytochrome c oxidase-I (CO-I). Yet another easy, accurate, and economical method of species discrimination is by developing species-specific markers, which produce specific amplicon for the species in question. The method is handy because it is not limited by life stages, sex, polymorphism, and other factors. Herein, we measured the usefulness of CO-I for the species discrimination of mirids in India viz. Helopeltis antonii Signoret, H. thievora Waterhouse, H. bradyi Waterhouse, and Pachypeltis maesarum Kirkaldy in their various life stages. Furthermore, our study showed the utility of species-specific markers in differentiating H. antonii (295) and H. bradyi (514) regardless of their life stages. Analysis of CO-I gene revealed <1% intraspecific divergence for all four species examined, whereas the interspecific distances ranged from 7 to 13%. This study showed that the DNA barcode and species-specific markers will aid the identification of mirids in India and will stand as a decisive tool in formulating integrated pest management (IPM) strategy, quick identification of invasive and cryptic species, haplotypes, biotypes, and other factors, if any.

Speciation usually is conceptualized as occurring via three biogeographic modes: allopatry, parapatry, and sympatry. Sympatric speciation has been the most controversial because of the difficulty of developing plausible theoretical models in which the homogenizing effects of gene flow are sufficiently overcome to permit genetic divergence to occur in the absence of geographic barriers restricting gene flow. Recently, a number of hypothetical models for sympatric speciation have been advanced and several candidate study systems have provided evidence of sympatric divergence, although many of the systems so identified involve introduced species, especially in the cases of host-race formation in phytophagous insects, which expand their host range and use a novel host. Although these cases demonstrate the reality of sympatric divergence, they do not address which mode of speciation predominates in indigenous communities. Asphondylia borrichiae Rossi & Strong has been proposed as a potential example of sympatric divergence in a fully indigenous system, based on the results of a host-choice experiment involving three host-plant species. In the current study, we report significant differences in the genetic composition of midge populations collected from each host in situ, supporting the hypothesis of sympatric genetic divergence among the morphologically identical host-associated populations of A. borrichiae and consistent with host fidelity in oviposition choice.

We created a detailed model of the Maruca vitrata (F.) and cowpea [Vigna unguiculata (L.) Walp] system to study the possible evolution of resistance by the insect to transgenic insecticidal cowpea, which is under development. We focused on population dynamics and genetics in a region of west Africa. We simulated single-toxin and pyramided (two-toxin) cowpea and emphasized conservative, worst-case scenarios in our analysis. The results indicate that as long as a pyramided, transgenic cowpea can be developed, seed saving by farmers and reliance on natural refuge are not major problems for resistance management. Furthermore, it is possible that one or both toxins in the pyramid may not need to be high dose for evolution to be delayed significantly (>20 yr or 80 generations for resistance to become a concern if transgenic cowpea is deployed in areas where M.vitrata is endemic). If efforts are made to deploy transgenic cowpea only into the regions where M.vitrata is not endemic, then there is little to no concern with resistance emerging in the M. vitrata population.

A 4-yr on-farm study was conducted in the Philippines between 2006 and 2009 to determine if there are any long-term impacts of Bt corn on the arthropod community on commercial farms and in adjacent riparian areas. Arthropod counts were gathered by visual inspection of corn plants in three pairs of commercial farms and by sweep sampling in riparian sites close by. Sampling showed that species composition between Bt and non-Bt corn and between riparian areas adjacent to Bt or non-Bt corn were similar. Principal response curves and analysis of variance showed that there were no adverse effects of Bt corn on the abundance of natural enemies either in crops or adjacent riparian sites. The frequently observed natural enemies in Bt corn were the predatory coccinellid beetle, Micraspis discolor (F.) and spiders (Araneae). Arthropod diversity was similar 1) in Bt- and non-Bt corn and 2) the adjacent riparian areas. Taken together, the two parts of this study show that Bt corn does not have any long-term adverse effect on arthropod communities in corn (Zeamays L.) or in adjacent riparian ecosystems. The methods and results described in this study will be useful to Philippine government regulators in making recommendations and policy guidelines related to monitoring for environmental effects of transgenic crops. The current study did not attempt to demonstrate the direct exposure of arthropods in riparian sites to transgenic Cry1Ab protein that might come from adjacent Bt corn fields; that would require different experimental methods but the current study suggests such effects are unlikely.