Environmental Entomology最新文献

The fall armyworm Spodoptera frugiperda (J. E. Smith, 1797) has evolved resistance to different Bt maize technologies carrying Bacillus thuringiensis genes. One hypothesis for the rapid evolution of resistance may be associated with the species' ability to multiply and survive on alternative host plants, especially during the off-season of the main crops. The aim of this study was to evaluate the biological parameters and fertility life table of susceptible (SS), heterozygous (RS) and resistant (RR) strains of S. frugiperda to Bt YieldGard VT PRO maize when kept in summer-winter cover crops. Based on the results, S. frugiperda did not survive on weeds Barnyardgrass (Echinochloa crus-galli). SS, RR, and RS larvae fed on white oats (Avena sativa), ryegrass (Lolium multiflorum), maize (non-Bt isoline) showed an egg to adult generation of approximately 30 d. The RS strain performed better than both the SS and RR strains, this is consistent with the individuals' high heterosis index. In addition, the insects reared on these hosts showed the highest reproductive rates (Ro = 496.2 to 578.1) and growth rates (rm = 0.143 to 0.185). In contrast, sorghum (Sorghum bicolor) or Persian clover (Trifolium resupinatum) prolonged the cycle by 4 d and reduced egg-to-adult viability parameters by 13%, larval weight (0.057 to 0.74 mg), pupal weight (0.36 to 0.86 mg), Ro (196.4 to 324.0), and rm (0.104 to 0.122). However, it is worth noting that all the host plants evaluated, except for Barnyardgrass, can serve to multiply S. frugiperda in the field and favor the reestablishment of the insect during the corn off-season and, consequently, accelerate the evolution of the pest's resistance.

Previous studies investigating the relationship between landscape composition surrounding a crop, and either plant pathogen vectors or vector-borne plant pathogens in the crop, have not observed consistent relationships, and no quantitative synthesis of the current literature has been conducted. We conducted a meta-analysis of 289 published effect sizes from 28 studies to better understand the relationships between landscape composition and plant pathogen vectors or vector-borne pathogens, while considering a series of biological, ecological, and environmental factors that may contribute to variation in the relationships. We found that vector and vector-borne pathogens were positively associated with landscape composition metrics, including the percentages of the landscape surrounding the study areas that were crop, non-crop, and natural habitat but not with habitat diversity. Vector host plant specialists exhibited a significant positive association with various landscape composition metrics, while host plant generalists did not, supporting the idea that specialists are more dependent upon specific host landscape features, whereas generalists have hosts that are generally more abundant across various landscapes. Measurements of both abundance and incidence of pests exhibited significant positive associations with landscape composition metrics. For both persistent and non-persistent pathogens, the positive association between pathogens and landscape composition became stronger at larger spatial scales (500 to 10,000 m). This meta-analysis demonstrated that increasing the percentage of crop, non-crop, or natural habitat within a landscape can increase vectors or vector-borne pathogens in the crop. However, the specific landscape feature that contributes to increased pest abundance or incidence will depend on the crop-pest system.

The maize caterpillar, Mythimna loreyi (Duponchel, 1827) (Lepidoptera: Noctuidae), is an important migratory pest for agricultural production in Asia, but its flight performance remains poorly understood. Here, we utilized a computer-monitored flight mill system and a stroboscope to assess how adult age, sex, temperature, and relative humidity affect the flight capacity of M. loreyi. The results indicated that the flight ability of M. loreyi was most highly developed in 2-day-old adults and decreased significantly with age. Two-day-old adults under conditions of 24 °C and 80% relative humidity throughout a 12-h scotophase recorded a total flight distance of 23.5 ± 2.8 km for males and 27.2 ± 2.6 km for females, suggesting that M. loreyi has a strong potential for long-distance migration. Temperature and relative humidity had significant effects on the flight performance of M. loreyi, with the maximum flight capacity in the range 20 to 28 °C and 50% to 85% relative humidity. In addition, the wingbeat frequencies of M. loreyi adults ranged from 22.6 to 57.6 Hz and 18.6 to 56.8 Hz among different age groups and temperatures. The highest wingbeat frequency (46.0 ± 0.8 Hz) was recorded for 6-day-old moths. Wingbeat frequency increased with temperature, with maximum (47.0 ± 0.6 Hz) recorded at 36 °C. Wingbeat frequency of male moths was significantly higher than that of female moths. These findings provide a foundation for understanding M. loreyi's migration behavior and can guide the improvement of regional monitoring strategies.

Two species of Leucotaraxis Gaimari & Havill (Diptera: Chamaemyiidae), predators of hemlock woolly adelgid, Adelges tsugae Annand (HWA, Hemiptera: Adelgidae) on western hemlock, Tsuga heterophylla (Raf.) Sarg. (Pinales: Pinaceae), in western North America, are currently being investigated as potential biological control agents for HWA in eastern North America. To evaluate their potential for biological control of HWA on eastern hemlock, Tsuga canadensis (L.) Carrière (Pinales: Pinaceae), we conducted laboratory studies to assess their feeding and oviposition responses to different HWA densities. Leucotaraxis argenticollis Zetterstedt was only assessed on the first of 2 generations of HWA, while Leucotaraxis piniperda Malloch was assessed on both generations of HWA, as their phenology in the eastern United States is unknown. Increasing prey densities of HWA ovisacs were used to assess the oviposition of both species of silver flies. Leucotaraxis argenticollis significantly increased their oviposition in response to an increase in HWA densities on the sistens ovisacs containing progrediens eggs, while Le. piniperda showed no significant response for either generation of HWA. Overall, there was no difference in oviposition rates between species; however, Le. argenticollis laid their eggs more frequently on or under the ovisac than Le. piniperda. Increasing prey densities of HWA ovisacs were utilized to assess the feeding response of Le. argenticollis larval feeding. Leucotaraxis argenticollis significantly increased their feeding in response to increased prey densities. These laboratory studies suggest Le. argenticollis has potential as a biological control agent, and both species warrant further investigation.

Bumble bees (Hymenoptera: Apidae: Bombus spp.) are crucial pollinators of many natural and agricultural systems, but some species are undergoing declines in response to diverse stressors, including climate change and habitat loss. For example, some species (eg Bombus affinis) have undergone significant range contractions, while others have remained stable or even expanded their range, and the factors driving this disparity remain unclear. We used records of preserved specimens from over 35 unique sources to study occupancy trends in 9 common Indiana bumble bee species from the early 1900s until 2022. We created 2 occupancy models to estimate the effects of crop richness, crop extent, and temperature on county-level bumble bee occupancy. We found that the probability of occupancy increased over time for 4 species (Bombus bimaculatus, Bombus citrinus, Bombus fervidus, and Bombus griseocollis). Responses to temperature were highly variable among species, with Bombus fervidus and Bombus vagans having a significantly lower likelihood of occupancy with higher temperatures. Crop richness and crop extent did not have a significant effect on occupancy. With future climate warming, some bumble bee species are more likely to persist than others, which could lead to significant restructuring in pollinator communities in Indiana. Our dataset al.o reveals that only 47 out of 92 Indiana counties have specimen records post-1990, highlighting the need for expanded sampling throughout the state. With declines already documented in the Midwest and beyond, it is crucial to continue monitoring our pollinators to understand how to best conserve their populations.

The tropical nut borer, Hypothenemus obscurus (F.) (Coleoptera: Curculionidae: Scolytinae), is a significant economic pest in Hawaii's macadamia orchards, contributing to substantial pre- and postharvest losses. Existing management strategies relying on cultural controls and generalist predators have been proven inefficient. This study developed and evaluated a trap-based monitoring system integrating both olfactory and visual cues to improve pest monitoring and management for H. obscurus. Field trials conducted over 2 yr assessed various alcohol-based lure formulations and trap color preferences under commercial orchard conditions. Results demonstrated that lures containing higher proportions of methanol, particularly at a 100% concentration and 3:1 methanol-to-ethanol ratio, captured significantly more H. obscurus than ethanol-only lures. Trap placement at 1.5 m in the lower canopy yielded higher captures compared to ground-deployed traps. Color trials revealed that transparent bottle traps achieved the highest captures, followed by brown and red, while yellow and white traps were the least effective. In summary, methanol-baited, transparent bottle traps deployed in the lower canopy of trees proved to be most effective in capturing H. obscurus, highlighting the importance of integrating semiochemical and visual stimuli as well as trap placement to enhance trap effectiveness. The implications of our findings for the enhancement of early detection, timely interventions, and improvement of integrated pest management strategies for H. obscurus are discussed.

The soybean aphid, Aphis glycines Matsumura, is a major pest that can significantly reduce soybean yields during heavy infestations. Planting resistant varieties is essential for managing this pest, requiring effective breeding and screening. In the United States, Dowling is resistant while Williams 82 is susceptible to A. glycines. This study assessed A. glycines from Harbin, China, feeding on soybean varieties Dowling, Williams 82, Shennong 9, and line P 3 under controlled conditions. Results showed that A. glycines thrived on Dowling and Williams 82, with no significant differences in longevity, oviposition, or fecundity. Line P 3 showed greater resistance to A. glycines than Dowling, with shorter adult longevity and lower fecundity. Shennong 9 was more susceptible than Williams 82, exhibiting longer adult longevity and higher fecundity. P 3 may serve as a valuable resource for breeding resistant soybeans, while Shennong 9's susceptibility could aid in control strategies. These results are crucial for developing A. glycines-resistant soybean varieties.

Stink bugs (Hemiptera: Pentatomidae) have emerged as an important pest species complex in soybean production systems across the southeastern United States. Changing cropping practices and climatic conditions are reshaping the stink bug communities in the region. Understanding community differences will be important to tailor integrated pest management programs sensitive to variation in species composition. In this 3-year study (2022-2024), we characterized stink bug diversity and abundance in 154 commercial soybean fields distributed across 3 soybean-producing ecoregions (Coastal Plain, Piedmont, and Mountains) in 2 southeastern states, North Carolina and Virginia. Standardized 25-sweep samples were collected at 10 locations per field during the soybean reproductive stages. Field-level samples were used to evaluate the probability of exceeding the recommended economic threshold for damage. We observed differences in stink bug community composition and spatial variation in the distribution of common stink bug species across the ecoregions. Additionally, the risk of soybean fields exceeding the recommended economic threshold differed across the ecoregions, with the Mountain region at the greatest risk. This result highlights the importance of regionally specific scouting and management recommendations that are sensitive to species composition differences. This work also provides a benchmark to assess range shifts of stink bug species in North Carolina and Virginia.

We reared the predatory bug Orius albidipennis Reuter (Hemiptera: Anthocoridae) on a diet of Ephestia kuehniella Zeller eggs and bee pollen and subjected separate lines to selection for either increased or decreased fecundity. After 18 generations, we obtained a line with 76% greater egg production compared to unselected controls, with fecundity exhibiting an estimated heritability of 0.10 ± 0.005. The line selected for low fecundity experienced rapid population decline followed by extinction after 6 generations. Compared to controls, the high-fecundity line showed no reduction in longevity or functional response to female Tetranychus urticae as prey, suggesting no inherent tradeoffs in either lifespan or foraging efficiency, which might affect biocontrol efficacy, although this may not hold true in nature where energy demands will be greater than in a laboratory setting. The high-fecundity trait remained stable for 9 generations following relaxation of selection. Although genetic admixture with wild populations, along with unknown selective forces, are likely to eventually dilute trait expression in the field, the high reproductive rate obtained via artificial selection could serve to reduce production costs substantially and improve levels of pest control for several generations post-release in augmentation applications.

The cuticular wax layer of insects comprises a blend of compounds ranging from ∼20 to 40 carbons, which can be straight-chain or branched, saturated, or unsaturated hydrocarbons, along with lesser amounts of long-chain alcohols, aldehydes, ketones, and fatty acids. The species specificity of the chemical profiles of wax layers suggests they may be exploited as chemotaxonomic characters, and they have proven useful for differentiating between morphologically similar species of many insect taxa. We tested the hypothesis that cuticular hydrocarbon (CHC) profiles offer a convenient method of discriminating between morphologically similar species of cerambycid beetles, in particular, the congeners Graphisurus despectus (LeConte in Agassiz 1850) and G. fasciatus (Degeer 1775) (subfamily Lamiinae: tribe Acanthocinini) that are native to the eastern United States. Adults of the 2 species were collected from field sites in east-central Illinois, their cuticular lipids were extracted, and the CHC compositions were characterized by coupled gas chromatography-mass spectrometry. Analysis of the CHC profiles revealed distinct patterns consistent with the designation of the congeners as distinct species, and particular diagnostic hydrocarbons were identified for each species. Sanger sequencing of the mitochondrial cytochrome oxidase I gene supported the hypothesis that the CHC profiles were reliable characters for differentiating the 2 species. These findings demonstrate that analysis of CHC profiles of cerambycid beetles may provide a convenient, rapid, and inexpensive method for reliably distinguishing morphologically similar species, and can guide identification of diagnostic taxonomic characters.