Development of green peach aphid, Myzus persicae (Sulzer), was modeled under high and fluctuating temperatures to determine what effects an increase in mean summer temperatures of 2.5–3.5°C would have on green peach aphid populations in Minnesota and North Dakota. Green peach aphid developed faster and had greater fecundity under fluctuating conditions. The constant temperature model failed to predict observed development under fluctuating temperatures (R² = 0.01). Optimal temperature for green peach aphid population growth was 26.7°C. The lower and upper developmental thresholds were 6.5 and 37.3°C, respectively. Under optimal conditions, intrinsic rate of increase was 0.356, and population doubling time was 1.95 d. At optimal fluctuating temperature conditions, one female aphid produced 12.2 progeny each week while under the most favorable constant temperature conditions; each female aphid produced only 5.9 progeny. Green peach aphid was able to survive 1 h each day above its calculated lethal death point of 38.5°C. It seems that, in midwestern North America, green peach aphid would benefit from an increase in mean summer temperature (20°C) of 2.5–3.5°C.

The cactus moth, Cactoblastis cactorum (Berg), is an invasive pest of Opuntia spp. Since its arrival in the Florida Keys in 1989, it has moved rapidly up the east and west coasts of Florida, threatening to invade the southwestern United States and Mexico. Female moths produce a sex pheromone that attracts male moths. In this study, we report on mating behavior observed in the laboratory and the identification of putative pheromonal chemical components based on mass spectral analysis of volatiles collected from virgin female moths and from solvent extraction of excised glands. Three candidate components, formulated on rubber septa in different release rates and ratios, were tested in laboratory olfactometer and flight tunnel experiments, and in field tests in areas with known feral populations of cactus moths. Lures formulated with the three-component blend of 54% (Z,E)-9,12 tetradecadien-1-ol acetate, 42% (Z,E)-9,12 tetradecadien-1-ol, and 4% (Z)-9- tetradecen-1-ol acetate were the most effective, although changes in the ratio of these components had little effect on lure efficacy. For field deployment, traps baited with synthetic lures with a 1 mg load of the three component blend captured equal or higher numbers of males than traps baited with two virgin females. Trapping systems using this pheromone-based attractant will be useful for population delineation in areas currently infested.

Cicadellids (Homoptera: Cicadellidae) are occasional pests of vineyards in temperate areas, and unchecked populations can build up to high densities to cause leaf burn followed by defoliation and yield loss. Therefore, an optimal sampling scheme would allow determination of risk at minimal cost. Because the development of leafhopper nymphs and feeding injury is closely tied to temperature, a model driven by the accumulation of degree-days was developed to predict leafhopper cumulative abundance at 5, 50, and 95% levels in vineyards. The model was based on 22 data sets collected over 7 yr in three vineyards in southern Quebec. It was based on the cumulative abundance of nymphs of the eastern grape leafhopper; the grapevine leafhopper; the threebanded leafhopper; the Virginia creeper leafhopper; and Erythroneura vitifex Fitch. The lower threshold temperature for development was 8°C. Paired t-tests and the forecasting efficiency confirmed the validity of the model. The model indicated that monitoring for leafhoppers in vineyards should be initiated at 630 DD (5% cumulative abundance) and terminated at 1,140 DD (95% cumulative abundance). Maximum abundance would be between 850 and 860 DD (50% cumulative abundance) calculated from 1 March.

We conducted two experiments to develop a gravimetric method for determining the stadia of Callosobruchus maculatus developing in cowpeas. An important step was to develop regression equations for predicting weight changes in uninfested cowpeas to correct for changes that occur in weight as a result of changing environmental conditions, such as temperature, relative humidity, and barometric pressure. This was vital because we needed to have a way of determining weight changes in infested peas that were caused by the insects developing within them; even the weight of uninfested peas changed over the course of the experiments. The observed weight of each infested pea was corrected based on the proportion weight change in uninfested peas each time weighing was done to get an estimate of the cumulative change in weight caused by the presence of the insect. For each infested pea, cumulative change in weight was plotted against time, and plots were analyzed to determine whether a pattern existed that could be used to consistently distinguish stadia. In the second experiment we used an ultrasonic detector to validate results from the gravimetric method. We found that the gravimetric method provided accurate information on duration of the egg, larval, and pupal stages of C. maculatus; however, the gravimetric method could not reliably distinguish the four larval stages of C. maculatus. Our paper also discusses practical applications of the gravimetric method for determining the stadia of internally feeding insects in the context of the current and previous research.

Little is known about the habitat preferences of Macrothele calpeiana (Walckenaer, 1805), an endangered endemic Iberian spider. In this paper, we seek to identify its distribution determinants and to disentangle their independent from combined effects. Generalized linear models (GLMs) of species presence–absence in southern Iberia were built from available distribution information and a variety of climate, land-use, and vegetation-vigor explanatory variables. Their independent and combined effects were estimated using variation and hierachical partitioning. On the scale of this work, M. calpeiana distribution is determined mainly by climate variables, especially by those related with precipitation; high annual precipitation and high precipitation periodicity favors the spider. Temperature is also important, because the species is not found where temperatures reach extremes. Whereas independent vegetative vigor and land-use effects, not easily separated from climate effects, are negligible, loss of forest to agriculture seems to have a negative effect. The slight positive effect of artificial surfaces cannot be directly attributed to anthropogenized-habitat preferences. Failure of climate model interpolation to predict some core species distribution areas in southern Iberia is discussed. The need for reliable distribution information from which to develop accurate habitat models is highlighted.

We studied the adult behavior, oviposition, and larval and pupal development of Hoplia philanthus Füessly (Scarabaeidae: Melolonthinae) in the field and laboratory in Belgium. Adult emergence was observed in the first week of June 2000, 2001, and 2002, peaked ≈2 wk later, and continued until the last week of the month. The average sex ratio of emerging adults was 1.3:1 (male and females) during the collection period. Adults were observed feeding mainly on leaves of Betula utilis variety jacquemontii (B. u. Doorenbos) and Carpinus betulus L. During the day, H. philanthus adults were most active at 1400 hours (GMT 1.00). Oviposition started in the last week of June and lasted until the end of July. Each female deposited ≈25–40 white eggs at a depth of 10–15 cm in soil. Eggs hatched 28 ± 5 d after being laid at an average monthly soil temperature of 18.1°C. Three larval instars could be discerned by head capsule width; all larval instars fed on grass roots. The first-instar larvae were found in the last week of July 2000; second instars appeared mostly in the second week of September 2000 and could be found until May 2001. Third instars were found from the second week of June 2001 until April 2002. Pupae could be found from the first week of May until the end of the month. The duration of the pupal stage was 28 ± 5 d at an average monthly soil temperature of 16.5°C. According to these observations, H. philanthus has a 2-yr life cycle.

Turfgrass lawns support a diverse fauna of arthropods including ground beetles, a major predator and seed feeding group. Despite their ubiquity and ecological roles, few studies have looked at ground beetle diversity and composition within lawns. We studied assemblages of Carabidae and their seasonal abundance in a newly established and a 10-yr-old lawn located in Quebec City, Canada. Carabids were sampled from May to November in 2003, 2004, and 2005 using pitfall traps. A total of 17 species in 10 genera and 7 tribes were identified. In the new lawn, three ground beetle species represented 72% of total Carabidae: Harpalus rufipes (30%), Clivina fossor (30%), and Amara aenea (12%). In the older lawn, the most abundant species were Amara aenea (31%), Bembidion mimus (21%), and Dyschirius brevispinus (19%), representing 71% of total Carabidae. Ground beetles were six times more abundant at the older site, and there were minor differences in species diversity between sites and years. For the most abundant Carabidae collected, seasonal abundance patterns were similar for A. aenea and B. mimus with peak abundance in July and/or August. For Harpalus rufipes, seasonal abundance was higher in 2003 and 2005 than in 2004, suggesting a biennial life cycle.

Ground-nest densities and nesting habits of 13 ant species were quantified in five postfire age classes (1, 9, 23, 47, and 79 yr old) in the lichen–spruce woodland of Quebec, Canada. There were no significant differences in ant nest densities between age-classes (average of 163 nests/ha), but there were significant differences in ant community structure. Ant communities were dominated by Formica podzolica, F. aserva, F. hewetti, and Myrmica detritinodis, which accounted for 77% of occupied nests. Some species (e.g., F. podzolica) were specialists in their nesting habits, whereas others (e.g., F. aserva) were generalists and built their nest in a variety of substrates. Nest densities of F. aserva correlated with several habitat factors, but these correlations could have been spurious because they were not related to this species’ nesting habits. However, significant positive correlations found between Camponotus herculeanus and Leptothorax canadensis and coarse woody debris (CWD) may be biologically significant, because these two species nested exclusively within CWD. Nest densities of M. detritinodis and M. fracticornis were relatively high in the youngest and the oldest age classes, resulting in a negative correlation with CWD. We suggest that the distribution of these two species is caused by their preference for older forests to a high rate of fire survival and possibly to competitive release in the year after disturbance. According to canonical correspondence analysis, at least 75% of the variation in ant species cannot be explained by the habitat factors measured. Future research should include, therefore, experimental manipulations to determine the extent to which other factors, such as interspecific interactions, may structure ant communities in lichen–spruce woodland.

Detritivores play important roles in energy and nutrient flow in riparian ecosystems. Endemic crickets (Gryllus alogus Rehn) and exotic isopods (Armadillidium vulagare Latreille and Porcellio laevi Latreille.) are abundant detritivores in riparian forest floors of central New Mexico. To determine how disturbance history affects the abundance of these detritivores, we installed pitfall traps in plots that had flooded, burned, or had no recent disturbance. We also measured vegetation composition to examine the relationship between plant community composition and detritivore abundance. Crickets were most abundant in the two plots that had flooded but were rare in recently burned, nonflooded plots. Isopods were most abundant in a wildfire plot with high vegetation density and mesic conditions but were also abundant in unburned plots. Isopods were rare in the plots that had recently burned or had flooded. Multiple regression model selection results suggest that cricket abundance is best explained by plot-related variables and is partly explained by recent disturbance history. Isopod abundance was best explained by disturbance history and vegetation characteristics. Cricket abundance was positively associated with flooding while isopod abundance was positively associated with vegetation density and fire and negatively associated with flooding and exotic saltcedar. These results show that flooding can lessen the negative impact of wildfire on native detritivores and reduce the abundance of exotic species.

Urbanization has been observed to affect arthropod communities through mechanisms such as removal of habitat and creation of habitat remnants. However, very little research has been conducted that simultaneously analyzes the range of anthropogenic, remnant, and quasi-natural land uses in a city as potential habitat for arthropods. Here we report on >2 yr of a long-term study of ground arthropods of Phoenix, AZ, focusing on the communities assembled in agricultural fields, commercial sites, mesic and xeric residential yards, desert remnants surrounded by the city, and peripheral natural desert. Agricultural fields and mesic residential yards generally supported the greatest number of individuals and taxa, showed the best separation from other types in ordination analyses, and had the greatest number of significantly associated taxa in indicator species analysis. Thus, of the urban habitats, two heavily irrigated and highly productive land use types seem to stand apart from the others in most community measures. Outlying desert sites also supported significantly associated taxa, including those not found regularly in desert parks and members of higher trophic levels less common in the city. Despite this, outlying desert and desert parks supported similar taxon richness. Xeric residential yards and commercial sites did not support any taxa not found in other land use types. While our results may be dependent on the location of Phoenix in the water-limited Sonoran Desert, we urge broader consideration of highly modified urban landscapes as wildlife habitat.

This study recorded the arthropod communities present in three commercially available beneficial insect habitat seed mixes (Peaceful Valley’s Good Bug Blend, Clyde Robin’s Border Patrol, and Heirloom Seed’s Beneficial Insect Mix) and three commonly grown cut flower/herb plantings (Zinnia, Celosia, and fennel). Communities were sampled three ways: (1) foliar and floral collections were made using a D-Vac and aerial nets, and insects were identified to family and assigned to feeding groups; (2) pitfall traps were used to collect ground beetle and ground-dwelling spider populations; and (3) evening observations recorded visits by noctuid (Lepidoptera: Noctuidae) and hawk moths (Lepidoptera: Sphingidae) to flowers. Overall, Good Bug Blend had the highest abundance and diversity of beneficial parasitoids, predators, and ground beetles. However, along with Border Patrol, it also harbored the highest diversity and abundance of crop-feeding herbivores. The Border Patrol plantings had the highest diversity and abundance of insect herbivore crop pests and the highest number of feeding visits by pest moth species during evening observations. The moth visits were most likely caused by the presence of evening primrose in this mix that blooms at dusk when moths are most active. Celosia harbored the greatest diversity and abundance of predators and parasitoids in the cut flower/herb plots. Fennel had the lowest overall abundance and diversity of all the plantings, but this may have been caused by late summer flowering.

The structure of the ground-dwelling beetle community at two forested sites in northern Delaware was compared by examining composition and abundance at the species or genus level for five target families and at the family level for all other Coleoptera. The beetle communities at an isolated 15-ha woodlot and a nearby plot of relatively continuous forest were sampled using pitfall traps during 2000 and 2001. The results showed an absence or reduced abundance of many beetle taxa in the isolated woodlot relative to the continuous forest site and elevated abundances of a few taxa. Most notably, the species richness of poorly dispersing species of carabid beetles was lower in the isolated woodlot, with 12 of 19 brachypterous species completely absent from pitfall samples. Although this study does not constitute a test of habitat fragmentation hypotheses, the data do suggest that the beetle community in the woodlot may be suffering from isolation effects. The estimated response to fragmentation was correlated with body size for the 19 most common carabid species caught, suggesting that body size may be a useful predictor of vulnerability to forest fragmentation. At least in Carabids, larger body size seems to be associated with greater susceptibility to fragmentation. A number of staphylinid beetle taxa were also significantly less abundant or absent in the isolated woodlot, as were some beetles in other trophic groups, including carrion beetles (Silphidae) and geotrupid beetles (Geotrupidae). Although it retains some faunal similarity with nearby continuous forest, the woodlot may be too isolated to sustain populations of some beetle taxa, especially large, poorly dispersing forest species.

Odonate nymphs are important predators of the immature aquatic stages of mosquitoes. Populations of the malaria vector Anopheles pseudopunctipennis Theobald (Diptera: Culicidae) can be efficiently reduced by extraction of filamentous algae from river pools in southern Mexico. Here, we examined the influence of this intervention on the diversity of odonates associated with mosquito breeding pools after annual extractions of algae from river pools in a 3-km section of the Coatán River, over a period of 2 yr. Odonate sampling was performed at monthly intervals in control and treated sections of the river for 4–5 mo after extraction in both years and before extraction in 1 yr. In total, 16 species, 10 genera, and 6 families of odonates were collected. Shannon diversity index values declined significantly during a period of 1 mo in 2001 and >5 mo in 2002. However, the abundance of odonates captured was not affected by algal extraction. In contrast, year-to-year variation in the diversity and abundance of the odonate community was strongly influenced by precipitation and river volume. Despite the importance of algae in river ecology, we conclude that the mosquito control intervention resulted in minimal impact on the odonate community in southern Mexico.

Large screened cages trials were conducted to assess the potential of honey bees, Apis mellifera L., to vector Beauveria bassiana (Balsamo) to canola, Brassica napus L., against the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois). The bees effectively vectored the inoculum from the hives to the crop. Conidia of B. bassiana was recovered from 100, 64–77, 70–82, and 47–83% of bees, flowers, leaves, and L. lineolaris samples, respectively, collected on four sampling dates in 2002 and 2003. Mean mortalities of L. lineolaris collected from the Beauveria-treated cages in the field were 56 and 48% compared with 9 and 10% in the controls on the first and second sampling dates in 2002, respectively, and 22 and 45% in the treated cages in the field compared with 15 and 22% in the controls on the first and second sampling dates, respectively, in 2003. These results indicate that bees may provide a new novel means for applying B. bassiana to manage L. lineolaris on canola. The benefits are better pollination, reduction in pest pressure of L. lineolaris, and reduced reliance on insecticides.

Multipiece sand columns were used to study the dispersal and interspecific interactions at different depths among three nematode species with different foraging strategies. Steinernema carpocapsae Weiser, strain ‘NY001’, an ambusher nematode, Heterorhabditis bacteriophora Poinar, strain ‘Oswego’, a cruiser nematode, and S. feltiae Filipjev, strain ‘Valko’, an intermediate nematode were applied to multipiece sand columns in single-, two-, and three-species combinations 7 d before host introduction. The effect of interspecific interactions on nematode performance was estimated by comparing the percent host infected by a nematode species at specified depths when applied alone to the performance of the same nematode species when applied in combination with other nematode species. All three nematodes were capable of infecting some proportion of hosts down to the 32.5-cm depth when applied singly. In nematode combinations, interspecific competition occurred, but negative impacts of competition on nematode performance were not observed at all depths. S. carpocapsae ‘NY001’ was only affected negatively in the surface layer when combined in the three-species combination but not in the two-species combinations. S. feltiae ‘Valko’ was positively affected by the presence of S. carpocapsae ‘NY001’ at 26- and 32.5-cm depths in the two-species combination. In the presence of S. carpocapsae ‘NY001’ and S. carpocapsae ‘NY001’ S. feltiae ‘Valko’, the performance of H. bacteriophora ‘Oswego’ was positively affected at 32.5-cm depth. The results suggest spatial niche separation of nematodes with different foraging and dispersal strategies that may contribute to coexistence in the field.

Xenorhabdus sp. (X. sp.) and Photorhabdus temperata subsp. temperata (Ptt) are the symbiotic bacteria of the entomopathogenic nematodes, Steinernema monticolum and Heterorhabditis megidis, respectively. When the nematodes enter target insects, the symbiotic bacteria are released into the insect hemocoel. The bacteria cause septicemia and kill the insect host. When ingested, the bacteria caused high mortality of third-instar larvae of Spodoptera exigua, but did not show such high pathogenicity to the fifth-instar larvae. The high mortalities in the third-instar larvae seem to be caused by antibiotic activity against Bacillus cereus, a gut symbiont required for optimal development of S. exigua. To increase their pathogenicity in the fifth instar, the bacteria should be delivered into the hemocoel. To this end, Bacillus thuringiensis aizawai (Bt) as a synergist was used to facilitate entry of the bacteria from the gut lumen into the hemocoel of S. exigua by its disruption of the insect gut epithelium. The bacterial mixture treatment was highly synergistic against the fifth-instar larvae of S. exigua. The synergistic effects were shown by the successful infection of X. sp. or Ptt in the insect hemocoel. This research shows a possibility that Xenorhabdus or Photorhabdus can be applied to kill S. exigua by oral treatment in a mixture with Bt.

The root-feeding weevil Cyphocleonus achates (Fahraeus) is a promising biological control agent for managing the exotic, invasive weed spotted knapweed. The objective of this study was to compare the relative and potentially interactive effects of competition and specialized herbivory on spotted knapweed fitness. Competition was assessed through three grass seeding treatments: a nonseeded control and seeding to long-lived wheatgrasses originating either from North America, Pseudoroegneria spicata (Pursh) A. Löve ssp. spicata, or Europe, Thinopyrum intermedium (Host) Barkworth and D.R. Dewey. Comparisons were made of above-ground biomass, stem length, number of flowers, and life stage densities for spotted knapweed plants either infested or free of C. achates and growing under one of the grass seeding treatments. Infested adult spotted knapweed plants had lower shoot weight, stem length, and flowers/plant. The density of adult spotted knapweed plants was lower in grass-seeded plots than in nonseeded control plots. Results indicate C. achates herbivory is correlated with a reduction in measures of fitness and reproductive potential in field populations of spotted knapweed in North America. Furthermore, these results suggest that this agent might play a significant role in reducing spotted knapweed populations when competitive grasses are also present.

Studies were conducted in apple, Malus domestica (Borkhausen), to evaluate the attractiveness of semiochemical-baited orange plastic versus the standard white plastic delta-shaped sticky trap in capturing adult codling moth, Cydia pomonella L. Initial field tests showed that both orange- and green-painted sex pheromone-baited traps caught more male codling moths than the unpainted white trap. An orange plastic trap caught a similar number of moths as the orange painted trap. The orange plastic trap caught significantly more moths in field tests than either a solid white plastic trap or a white plastic trap with an orange logo covering 25% of the surface of the trap. Trap color and light level (2.0 versus 6.0 lux) significantly impacted the proportion of male moths contacting and subsequently caught in sex pheromone-baited traps in a flight tunnel. A significantly higher proportion of moths flew directly into versus landing on the outside of orange than white traps. Capture of male moths flying into traps was reduced under the higher light level. Trap color did not influence the catch of female codling moths in traps baited with a combination of sex pheromone and pear ester in field tests or in traps baited with pear ester in the flight tunnel. The capture of female moths was reduced in the flight tunnel at the higher light level. We hypothesize that this effect of trap color on the capture of male codling moth is caused by both the lower overall reflectance and the absence of reflectance at wavelengths <560 nm in orange versus white traps.

The Costa Rican weevil, Exophthalmus jekelianus (White) (Coleoptera: Curculionidae), is an economically important defoliator of coffee, Coffea arabica, in the Turrialba region of Costa Rica. Preliminary observations of E. jekelianus behavior suggest a preference for shaded microhabitat, which could have important implications for E. jekelianus management. Our results support that E. jekelianus prefer shade to sun microhabitat in a controlled environment, and furthermore, that E. jekelianus location within the coffee agroecosystem is strongly influenced by both shade and the amount and type of fertilizer applied. We postulate that temperature and humidity of the microclimate surrounding a coffee plant and coffee plant nutritional quality are the key factors in determining microhabitat location for E. jekelianus. Our findings contribute to knowledge of curculionid microhabitat selection and provide novel approaches to monitoring and management of E. jekelianus on Costa Rican coffee.

Both environment and genotype have a significant influence on the foraging behavior of honey bees (Apis mellifera). We compared the colony-level foraging behaviors of two honey bee stocks at three different sites by sampling 50 foragers each from 16 Russian-hybrid and 16 Italian colonies distributed among the Coastal Plain, Piedmont, and Mountain regions of North Carolina. We detected highly significant differences in foraging behavior among the different sites, but we found very few differences between the stocks. Moreover, there were very few environment–genotype interactions on foraging behavior, suggesting that the effect of genotype does not vary significantly depending on the environment in which it is located. These findings suggest that, while there are some notable differences between Russian-hybrid and Italian honey bees, the environment has a relatively larger impact on honey bee foraging behavior for these two stocks.

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), is an important vector of Xylella fastidiosa Wells et al., a bacterium that has caused substantial losses in the viticulture and ornamental industries in California. Area-wide management programs have been implemented to reduce vector populations and limit the spread of this disease. However, there is still a lack of information on the factors that influence this insect’s movement within and between host crops. In this study, we used mark-release-recapture (MRR) to examine the dispersal of H. vitripennis in a mature orange grove, Citrus sinensis Osbeck. Insects were doubly marked with chicken or rabbit immunoglobulin G (IgG) proteins and fluorescent dusts to enable monitoring over several weeks. Our objectives were to examine the reliability of IgG protein markers relative to fluorescent dusts, determine how sharpshooter movement differed in this landscape relative to a previous study, and develop a better understanding of the biotic and abiotic factors that could influence sharpshooter dispersal. Linear regressions of recapture data with a diffusion model provided significant fits to the data in five of six releases. Recapture data were fitted to a diffusion model, and based on parameters generated with the model, estimated dispersal distances for H. vitripennis at 72 h showed 50 and 99% remained within annuli of 31 and 150 m from the release site, respectively. Flight activity was greatest between 1000 and 1400 hours, and no flights occurred between 2200 and 0600 hours. Only temperature explained a significant amount of the variability in recapture of H. vitripennis, with sharpshooters rarely trapped below 18°C.

We assessed the toxicity of permethrin residues from barrier treatments for mosquito control on monarch butterfly (Danaus plexippus L.) larvae and adults. The motivation for this study was an absence of work on the effects of this commonly used insecticide on nontarget herbivorous insects and the fact that monarchs’ host plant, milkweed (Asclepias spp.), is often found in treated areas. In one experiment, larvae fed leaves from naturally growing milkweeds in operationally treated areas were much less likely to survive than control larvae, even when treated leaves were collected up to 21 d after spraying. In a second experiment, larvae fed leaves from potted milkweeds sprayed with 0.5 and 0.1% dilutions of the operational dose had lower survival and longer development times than control larvae. In a third experiment, ovipositing females did not discriminate against permethrin-treated plants. Female survival in 0.66-m³ cages with plants sprayed 1 d earlier was very low, whereas survival was greater if plants were assayed 8 or 15 d later. In a fourth experiment, neither frequent overhead watering (versus watering from below) nor outdoor sunlight (versus in a glasshouse) over a 14-d period lessened the toxicity of sprayed plants to larvae. These findings indicate that monarch larvae and adults are likely to be killed if exposed to residues of permethrin after barrier treatments for mosquito control. Extent of mortality in a field population of monarch butterflies will depend, among other things, on the proportion of host plants that are treated in a given area.

We explored remote sensing methods for their potential to distinguish aphid- (Aphis gossypii Glover) and spider mite–infested (Tetranychus spp.) cotton (Gossypium hirsutum L.) from uninfested cotton. Field plots were established using selective and disruptive pesticides to establish a range of aphid and mite populations over 2 yr. Aerial and satellite remote sensing data in 2003 and 2004 were supplemented with ground-based remote sensing data in 2004 and by ground-truthing of arthropod populations in both years. Mite- and aphid-infested cotton was detected using aerial data in the green and near-infrared (NIR) wavelengths in 2003, with subeconomic threshold aphid population levels. At the time aerial data were collected, mite populations peaked at 95% leaves infested and exceeded treatment threshold levels of 30–50% leaves infested. However, the number of mites per leaf in the treatments was low to moderate (32, 9, 4, 6, and 2 average mites/leaf). Moreover, cotton infested with cotton aphids above economic threshold levels was consistently detected using NIR wavelengths from the satellite data in 2004. Similarly, aphid-infested cotton was detected at both sub- and supraeconomic threshold aphid levels using NIR wavelengths from the ground-based remote sensing data. Finally, accumulated mite-days were linearly correlated with a canopy, false color, and a vegetation index using satellite data in 2004. Wavelengths in the NIR were fair to moderately accurate predictors of aphid- and mite-infested cotton.

Insect traps of different designs should sample some species more effectively than others. I used three different traps to survey longhorned beetles (Coleoptera: Cerambycidae) at 43 locations throughout the state of Indiana to test the prediction that these traps would sample different assemblages of cerambycids. Nonmetric multidimensional scaling revealed that, while there was little difference between the assemblages sampled by Lindgren multiple funnel traps and Intercept panel traps, window traps caught quite different assemblages. Several species of cerambycids that showed differences in trap efficiencies seem to be differentially caught by different trap designs according to the nature of the larval host. These results can be used to plan monitoring according to the guild of the target beetles.

In this paper, we studied the use of polyethylene bubble wrap and corrugated cardboard bark traps to sample spiders inhabiting tree trunks, with special reference to test whether they function the same way despite the differences in the spider community imposed by the different tree species and surroundings and times of sampling. The survey was carried out from July 1997 to July 1998 in Turin, Italy, in a green urban area on three poplars and four American basswoods. Differences between the two methods were tested in terms of abundance, diversity, dominance, mean body length of specimens, and proportion of juveniles, calculating Spearman’s correlations. Three-factor analysis of variance, multiresponse permutation procedure, and indicator species analysis were used for further analysis. Results obtained by the two traps were correlated following a similar trend over sampling time. Bubble polyethylene seemed to be more effective than corrugated cardboard at trapping higher number of specimens. The dimension and total amount of interstices and the different microhabitat conditions of temperature and humidity seemed to be the main factors influencing spider composition in terms of the selected variables. On the basis of our results, polyethylene bark traps are recommended for sampling spiders living on trees. It is important to consider seasonality in experimental design, autumn being the period with the highest abundance of spiders but a lower level of diversity.

The effects of pollen of regular cotton and transgenic Bt CpTI cotton expressing the Cry1Ac protein of Bacillus thuringiensis and cowpea trypsin inhibitor (CpTI) as a food source for Trichogramma chilonis (Hymenoptera: Trichogrammatidae) were assessed in the laboratory by studying longevity, parasitization rate, progeny survival, and sex ratio. Females fed on suspension of pollen of regular cotton or transgenic Bt CpTI cotton in water lived as long as those fed on water alone or those that were unfed. However, the females’ longevity was significantly reduced compared with that of females fed on 10% honey alone or suspension of pollen of regular cotton or transgenic Bt CpTI cotton in 10% honey, either with or without eggs of rice moth (Corcyra cephalonica). T. chilonis females fed on suspension of pollen of regular cotton or transgenic Bt CpTI cotton in 10% honey parasitized more eggs and produced significantly more offspring than those fed on 10% honey or water alone, suspension of pollen of regular cotton or transgenic Bt CpTI cotton in water, or nothing. T. chilonis females fed on 10% honey parasitized more eggs and produced significantly more offspring than those fed on suspension of pollen of regular cotton or transgenic Bt CpTI cotton in water, water alone, or nothing. No significant differences were found among those feeding on suspension of pollen of regular cotton or transgenic Bt CpTI cotton in water, water alone, or nothing. The longevity, numbers of parasitized eggs, numbers of progeny emerged, and sex ratio of T. chilonis fed on suspension of pollen of transgenic Bt CpTI cotton in water or 10% honey did not differ significantly from those fed on suspension of pollen of regular cotton in water or 10% honey. Pollen and honey supplied a complete diet for reproduction and survival of T. chilonis, and transgenic Bt CpTI cotton pollen did not adversely affect T. chilonis.

Optimal oviposition theory predicts that females prefer a host that assures the highest offspring fitness. I compared the host preference of females and larvae of a lichenivorous moth, Cleorodes lichenaria, and subsequent larval performance on host lichens with laboratory experiments and field observations. Both females and larvae preferred Ramalina fraxinea and Ramalina farinacea over Xanthoria parietina and Parmelia sulcata. Larvae reached the pupal stage faster on Ramalina species than on other lichens, whereas other fitness parameters including larval survival and pupal size did not differ between the lichen species. Interestingly, growth rates before overwintering were higher on P. sulcata and X. parietina than on Ramalina species, whereas after overwintering, the situation was reversed. The results of this study support the preference–performance hypothesis. Females clearly preferred host lichens that ensure the shortest developmental period at the expense of higher growth rates at the beginning of the larval period. Moreover, ecological and/or evolutionary factors in addition to females’ oviposition in host selection of C. lichenaria seem to be important. Because more larvae were found on Ramalina species than expected according to the oviposition pattern of females, final host selection is at least partially determined by larval behavior. It is also suggested that the physical and chemical properties of the hosts may provide a basis for enemy-free space for larvae.

Physiological responses of the halophyte, Atriplex subspicata Nutt. Rydb., to defoliation injury were evaluated through a series of experiments measuring plant gas exchange, fluorometry, and enzyme activity. Leaves exposed to simulated insect herbivory exhibited reductions in photosynthesis, stomatal conductance, and transpiration. Carboxylation efficiency, maximum assimilation, and CO₂ compensation were also negatively associated with mechanical leaf injury. Insect injury by a herbivore generalist, Spilosoma virginica, also reduced photosynthesis and carboxylation efficiency within the saturated spectrum of A/C_i response curves. Initially, declines in photosynthesis occurred because of transient stomatal limitations. However, after time, mesophyll limitations impaired photosynthesis and the plant’s ability to compensate for injury. Fluorescence data and light assimilation responses indicated that defoliation did not play a role in limiting light reactions of photosynthesis. Enzyme analyses showed increased peroxidase activity with insect injury, suggesting the need for future characterization of oxidative enzymes, which have been associated with traits of resistance. Overall, we found a salt-tolerant plant to be susceptible to insect herbivory through a reduction in the efficiency of the plant to allocate energy resources. If salt tolerance comes at the cost of susceptibility to biotic interference, natural occurring halophytes or plants with transgenic salt tolerance may be at risk for heightened deleterious response to insect herbivory.

Neotyphodium coenophialum is a fungus that commonly grows endosymbiotically within cool season grasses. The fungus can provide protection against biotic stresses to its host through the production of alkaloids. We tested if combinations of two cultivars (Georgia 5 and Jesup) of tall fescue with different isolates of N. coenophialum alter resistance to the aphid, Rhopalosiphum padi, in a greenhouse experiment. Aphid populations grew faster on uninfected plants of both cultivars. In Georgia 5, all fungal isolates depressed aphid reproduction, whereas only one of three did so in Jesup. In choice experiments, we found aphids preferred uninfected blades over blades infected with any of the fungal isolates. We conclude that R. padi is sensitive to a variety of fungal isolate and plant cultivar combinations, but that genetic variation in both plant and fungus can influence the degree of resistance provided by the fungus.

Ecological effects of genetically modified plants cannot always be predicted based on knowledge of the plant species or transgene. We studied the effects of transgenic aspen (Populus tremuloides Michaux) with reduced lignin and altered growth phenotypes on the feeding performance of gypsy moth larvae (Lymantria dispar L.) and forest tent caterpillars (Malacosoma disstria Hübner). Developmental trials were conducted using one control line and four separate transgenic lines of aspen. Gypsy moth larvae showed a significant reduction in survival on one high-lignin reduction transgenic tree line relative to all other lines, but weights of surviving larvae were similar across tree lines. Forest tent caterpillars showed similar survival and weights on all tree lines. Trials were also conducted to evaluate whether gypsy moth larvae preferred feeding on high-lignin reduction transgenic aspen lines or control trees. While gypsy moth larvae showed no significant preference between the control line and the transgenic line that caused significant reductions in larval survival during developmental trials, they did strongly prefer transgenic leaves causing no such reductions in larval survival. Because effects on feeding larvae varied among tree lines, we concluded that any potential phytochemical alterations in the transgenic lines could not be directly linked to lignin reduction. Because only one transgenic tree line had a negative effect on the herbivores, we propose that this may be an indirect consequence of transgenic manipulation resulting from the insertion point of the antisense Pt4CL gene in the genome, rather than 4CL suppression or lignin reduction.

The impact of different levels of whole plant partial defoliation (WPPD) on the photosynthesis and primary metabolism of wheat, Triticum aestivum L., was evaluated at the vegetative and reproductive (grain-filling) developmental stages. Photosynthetic parameters such as photosynthesis, stomatal conductance, and transpiration, chlorophyll a fluorescence, and plant morphological parameters, such as main stem height, flag-leaf and undefoliated leaf areas, and number of tillers, were recorded 1 h and 1, 9, and 12 d after defoliation in 2004 and 1 h, 3 d, and 6 d after defoliation in 2005. Plants with high defoliation levels (i.e., defoliation > 75%) had ≈21 and 20% greater photosynthesis rates compared with control and low defoliation level treatments, respectively. Our data show that stomatal conductance for flag leaves was not significantly affected by WPPD. In addition, we did not observe a significant effect of defoliation on intercellular CO₂ concentrations or on transpiration rates remaining flag leaf tissue. Similar responses were observed for the overall photosynthesis of defoliated plants during vegetative stages. Whole plant source-sink manipulation of wheat by WPPD during the major plant developmental stages (i.e., vegetative and reproductive) did not elicit any significant long-term modifications to growth, morphological, or primary physiological characteristics of wheat plants.

We report the first study of gut-associated bacteria of bark beetles using both culture-dependent and culture-independent methods. These insects are major pests of pine trees but also contribute to important ecological functions such as nutrient cycling. We found members of the α- and γ-Proteobacteria and Firmicutes in larvae of the southern pine beetle, Dendroctonus frontalis Zimmermann. Sequences from three larval guts were grouped into one to three operational taxonomic units (OTUs) at 3% difference among sequences. Communities in adult southern pine beetle guts consisted solely of members of the γ-Proteobacteria. These could be grouped into three to five OTUs at 3% difference between sequences. These gut communities have relatively low species richness, which may reflect the specialization needed to exploit a nutrient-poor food source, colonize a chemically complex habitat, and maintain consistent associations with mutualistic fungi. However, there is considerable variation in gut microbiota composition among individual insects, suggesting the need for additional studies on sources of variation and potential substitutability among species performing similar functions.