Environmental Entomology最新文献

Evolution of resistance within insects to pest control has resulted in changes to the organism's morphotype, including changes in wing shape. Both geometric morphometric and finite element method (FEM) were used to examine wing changes in Helicoverpa zea sampled from 4 different Bt corn treatments in North and South Carolina, United States. The 4 treatments were pure-stand non-Bt corn (treatment 1); pure-stand Bt corn with 2 toxins (Cry1Ab and Cry1F; treatment 2); pure-stand Bt corn with 3 toxins (Cry1Ab, Cry1F, and Vip3A; treatment 3); and seed blended Bt corn with 80% containing 3 toxins (Cry1AB, Cry1F, and Vip3A) and 20% having no toxins (treatment 5). Geometric morphometric analyses revealed significant wing shape differences in both female and male moths were driven by moderately selected moths (treatments 2 and 5). Male and female moths, especially from treatment 5, had longer and more slender forewing shape conducive for longer distance flight. FEM modeling of the flight potential in both male and female H. zea revealed that the highest wing elastic deformation values for wind speed, indicating the most impact on wing structure, occurred for treatment 2> treatment 1> treatment 3> treatment 5. Wing elastic deformation was significantly more pronounced in female than male moths. In conclusion, we found that one generation of selection on Bt corn in the field could induce H. zea wing phenotypes more conducive for potential long-distance dispersal and should be further investigated by directly testing the impact on migratory flight. Our study contributes to the growing body of evidence that selection of H. zea on Bt crops may influence adult dispersal behavior.

The decreasing abundance of insect species is a common phenomenon of the present era. To detect the change in species abundance, it is essential to have a sufficiently long time series over which the change can be detected. We examined the time series of the abundance of 110 moth species using annual captures in a light trap operated nightly from April to November of 1967-1995. For each species, the time series was fitted by a state-space model allowing for a time-varying slope (ie for a locally linear trend with the slope allowed to change over time). We then determined the position in time and the length of the period when the estimate of the slope became significant. No significant change in abundance was detected for 65 species. Significant negative trends were established in 29 species; at first after 17 yr from the beginning of the study, significant positive trends were established in 16 species, with the earliest trend being detected after 15 yr. The trends were either transient or remained significant for the duration of the study (and possibly longer), demonstrating that the state-space modelling approach is suitable for detecting long-term changes in species abundance. The time series needed to be long (≥15 yr) to detect significant trends in abundance.

Plants emit hundreds, if not thousands, of different volatile chemical compounds, although the function of most individual volatiles remains elusive. Individual volatiles, as well as blends of many chemicals, are likely multifunctional in regulating plant interactions with different groups of insects, including herbivores, natural enemies, and pollinators. However, research on these insect groups has historically been siloed, limiting our understanding of connections between different volatile-mediated ecological processes and how to apply this knowledge to agroecosystems. Here, we review recent literature on volatile multifunctionality in mediating plant interactions with insect herbivores, natural enemies, and pollinators. Ultimately, we propose that future research shifts towards a holistic approach in the study of volatile-mediated interactions between plants and insect communities. By elucidating how specific volatiles, chemical classes, and blends regulate behaviors across different groups of insects, we will uncover new semiochemical tools for controlling pests and protecting beneficial insects in agroecosystems.

The unreasonable disposal of polyurethane leads to resource waste and environmental pollution. Black soldier fly (Hermetia illucens) larvae facilitate the bioconversion of various organic wastes, but the degradation of polyurethane by black soldier fly larvae and the response mechanism of black soldier fly larvae gut microorganisms remain unclear. In this study, a s tandard diet (CK), polyurethane foam, and starvation were applied to rear black soldier fly larvae. We found that 82% of black soldier fly larvae survived, and their weight increased by 19 mg per larva after 16 d of feeding with polyurethane foam and water. The consumption rate of polyurethane was 0.35 mg/day per larva, and the cellular texture of polyurethane foam was damaged. X-ray photoelectron spectrometer and Fourier transform infrared spectroscopy suggested that ester, ether and urethane bonds were cracked. Analysis of gut microorganisms indicated that Dysgonomonas, Morganella, and Klebsiella were the most abundant genera in CK, while Providencia, Scatolibacter, and Chryseobacterium were the most abundant genera in polyurethane, indicating that gut microbial community could respond to a harsh environment and offer a stable survival and adaption strategy for black soldier fly larvae. In addition, a polyurethane-degradation strain from black soldier fly larvae gut named Delftia sp. A2 was isolated, suggesting the potential of gut microorganisms to discover other functional strains. In summary, we found that black soldier fly larvae could survive and gain weight with the polyurethane as the sole substrate and polyurethane consumption influenced gut microbial community.

In response to herbivory, plants emit herbivore-induced plant volatiles (HIPVs), many of which attract natural enemies of herbivores. One such HIPV, methyl salicylate (MeSA), has been deployed in agroecosystems to enhance biological control. However, the broader agroecosystem context-including field-level management and landscape complexity-can strongly influence natural enemy community dynamics. In this 2-yr study, we evaluated the interactive effects of MeSA, field-level practices (eg pesticide use and cultivar selection), and landscape complexity on natural enemy communities and their ecosystem services (eg predation) across 50 georeferenced sites on the 3 largest commercial cranberry farms in New Jersey (USA). At each site, we deployed 2 yellow sticky traps-1 baited with MeSA and 1 unbaited control-to monitor natural enemies and placed sentinel caterpillar egg masses to measure predation. Landscape metrics were quantified within 100, 250, 500, and 1500 m buffers. MeSA significantly increased the abundance and diversity of natural enemies, including 7 taxa. Field management practices also interacted with MeSA, with greater fungicide use associated with higher Syrphidae captures. Landscape features further modified MeSA effects across spatial scales; for example, a higher proportion of wetlands within 1500 m enhanced Empididae captures on MeSA-baited traps. However, MeSA and its interactions had no detectable effects on predation rates. Together, these findings demonstrate that the efficacy of HIPVs like MeSA in attracting natural enemies can be context dependent, underscoring the importance of integrating field management and landscape ecology into conservation biological control strategies in agroecosystems.

Forecasting insect pest populations before crops are planted can help improve management and reduce pesticide use. Pests with long dispersal potentials and wide host ranges are difficult to predict but often cause losses in crops across broad spatial scales. Here, we use corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), as a case study of a regional crop pest to develop a forecasting framework. Models used historical H. zea trap data to predict populations across 12 states in the southern United States. Three regression models and one machine learning model were used to evaluate predictive performance in either space or time (ie year over year): linear regression model with fixed-effects only, Bayesian spatial-intercept model with and without fixed effects, and random forest. Results of random forest model provided the most useful information about H. zea population dynamics. We found that the location and year of trap location was the most meaningful predictor of H. zea abundance. The importance of local host crop abundance was less meaningful than the prior predictors. We also tested the importance of trap density to recover forecasting signals in North Carolina. Results showed that the trap density could be reduced by approximately 25% while still recovering reasonable predictions of H. zea density. However, it is clear from prior work that some trap locations are more important for prediction, so further assessment of the specific roles individual trap nodes present would be useful. Together this study highlights opportunities to improve annual H. zea forecasting across the US Cotton Belt.

Evaluation of potential classical biological control agents typically begins with laboratory testing for their fundamental host range. These experiments are intended to evaluate the propensity for nontarget attack but often do so in highly artificial conditions without considering the unique ecology of different agents. Understanding ecological characteristics early in evaluation is important as it can influence the methods or implications of host range tests and natural enemies are being increasingly found in adventive populations before host range testing is complete. We used Trissolcus japonicus, a potential classical biological control agent of the brown marmorated stink bug (Halyomorpha halys) to evaluate the ecological factors influencing nontarget host use of 5 different nontarget species. Female wasps were equally likely to select nontarget hosts when foraging for separated egg masses in cage experiments, contrary to expectations of previous host range tests. However, when hosts were placed close together, wasps selected the target host more often, suggesting T. japonicus does not perceive choices among separated egg masses. In no-choice experiments, we show that parasitoids exhibit polyphenism when developing on different sized hosts with corresponding reductions in egg load. Emergence success was also influenced by humidity for some but not all host species. Nutrient content differed between host species but was not clearly correlated with fitness of T. japonicus on different hosts. Our results suggest that T. japonicus is likely to parasitize nontarget species that share a niche with H. halys with high success in Podisus maculiventris and Chinavia hilaris hosts.

Artificial light at night (ALAN) can disrupt circadian rhythms and phenology for lepidoptera since photoperiod is a dominant cue for their life cycles. The goal of this study was to discover how ALAN exposure affects the timing of caterpillar development into chrysalis and metamorphosis into a butterfly. The painted lady butterfly (Vanessa cardui) frequents Texas from spring through fall. For this project, commercially sourced V. cardui caterpillars were used to study effects of ALAN in controlled indoor conditions, at a constant temperature of 23 °C. Throughout October 2020, April 2021, October 2021, and March 2022, caterpillars were exposed to 0, 9.5, 17.5, or 24 h of 300 lux white light emitting diode (LED) lights, and the days until chrysalis formation and butterfly emergence were observed. The 17.5 and 24 h ALAN light cycles caused butterflies to emerge 1 to 3 days faster than 9.5 h exposure. V. cardui development was expected to be faster under blue versus orange LED lights as their photoreceptors are more sensitive to blue wavelengths. This was tested in July through September of 2022 with exposure to 24 h white, blue, or orange LEDs versus no ALAN. Orange LED exposed butterflies emerged a day or 2 slower than blue or white LED exposed ones. Studies in 2023 with 12 h ALAN from white, blue, or orange LEDs yielded similar results, and hemolymph melatonin was reduced by blue LED exposures. Therefore, orange ALAN seems to be less disruptive to V. cardui metamorphosis than blue or white ALAN.

Invasion by non-native species is a growing threat to ecosystems and economies. In eastern North American woodlands, invasive exotic shrubs are displacing native plants and transforming understory communities. The displacement of native plants by invasive non-natives may reduce the resources available to higher trophic levels by supporting diminished arthropod communities. Despite a conceptual understanding of the potential for invasive shrubs to transform forest communities, little research has focused on characterizing the arthropod communities they support or their impact on higher trophic levels in eastern North American forests. To address this gap, we compared arthropod diversity, abundance, and community composition on a highly invasive shrub in southwestern Ohio, Amur honeysuckle (Lonicera maackii, Maxim., Dipscales: Caprifoliaceae), to a related, ecologically similar, native shrub, blackhaw (Viburnum prunifolium, Linnaeus, Dipscales: Adoxaceae), over a growing season. Relative to the native shrub, we found that L. maackii hosted a depauperate arthropod community overall, with about 25% fewer individuals and 28% fewer species than its native counterpart, V. prunifolium-primarily driven by a smaller herbivore community on L. maackii. In contrast, the abundance and richness of predatory arthropods were similar between the native and invasive shrubs. The arthropod communities on the native and exotic plants broadly overlapped in ordination space; however, community composition varied significantly, albeit modestly. These findings support the prediction that invasive plants support depauperate arthropod communities and provide reduced ecosystem services.

Spiders are dominant predators of agroecosystems, where they must adapt to regular disturbances. Recent studies show that their abundance in crop fields has declined, even at sites not sprayed with agrochemicals. These declines have been attributed mainly to reduced ecosystem complexity, which decreases herbivore populations and consequently limits the prey available to predators. Moreover, spiders, similar to other arthropods, are sensitive to frequent disturbances, such as plowing and mowing. In addition to these well-established drivers, undernourishment of spiders following repeated anthropogenic disturbance may further contribute to declines. We hypothesized that the food preferences of agrobiont spiders change in response to the previously provided diet. As a model, we used females of Heliophanus cupreus (Walckenaer, 1802) and Heliophanus flavipes (Hahn, 1832) (both Araneae: Salticidae), provided with Drosophila melanogaster Meigen, 1830 of various nutrient compositions, and then provided with a protein-rich intraguild prey represented by Dictyna Sundevaal, 1833 spiders and a lipid-rich agricultural pest prey represented by rose-grain aphids Metopolophium dirhodum (Walker, 1849). The prey preferences of the spiders changed in response to the previously provided diet. The lipid-rich diet increased spider survival and led to a preference for agricultural pest prey. In contrast, spiders on standard or protein-rich diets did not prefer agricultural pest or intraguild prey. Agrobiont spiders are able to adjust the spectrum of captured prey to pests dominating the respective crop type. However, the present findings suggest that the nutritional status of spiders may shape their food preferences, with potential, but untested, implications for predator-prey interactions in agroecosystems.