Environmental Entomology最新文献

Floral visitors adapt their foraging behavior through time and space, focusing their efforts to maximize floral resource collection. They are therefore vulnerable to variations in local environmental conditions. However, most studies focusing on understanding insect sensitivity to environmental variables are based on taxonomic identity rather than their role as pollinators. Consequently, frequent visits by neutral and antagonistic species can obscure the interactions between plants and effective pollinators unless their contributions to pollination are distinguished. Here, we investigated whether local environmental variables differentially influence the daily visitation frequency of effective pollinators compared to ineffective pollinators of cultivated highbush blueberry in southern Chile. Flower visitation was recorded alongside temperature, light intensity, and wind speed. Effective pollinators were defined as those that deposited more conspecific pollen on stigmas per visit than unvisited flowers, as opposed to ineffective pollinators. Our findings demonstrate that the dominant floral visitors in Chilean highbush blueberry crops are not necessarily the most effective pollinators. Although honeybees accounted for most floral visits, their pollination effectiveness was comparatively low. While light intensity positively influenced the frequency of all visitors (effective and ineffective pollinators) to blueberry flowers, wind speed had a negative effect. Although exotic managed bees may mask the visitation patterns of native insects, our results showed that they respond similarly to environmental variables. This suggests that, despite significant differences in pollination outcomes for the blueberry crops, all functional groups exhibit similar environmental sensitivity. Blueberry flower reward may interact with environmental variables to influence flower visitation patterns.

Soybean gall midge, Resseliella maxima Gagné (Diptera: Cecidomyiidae), is a soybean pest in the midwestern United States. Pterostichus melanarius (Illiger) (Coleoptera: Carabidae), an abundant predator in R. maxima-infested fields, feeds on and prefers R. maxima in the laboratory. However, it remains unknown if P. melanarius feeds on R. maxima in the field. We used experiments to assess whether P. melanarius feeds on R. maxima in the field and determine how quickly R. maxima DNA degrades in P. melanarius guts (ie the half-life). Molecular gut content analysis of P. melanarius adults collected from soybean fields in 2021 and 2022 detected R. maxima DNA in P. melanarius guts in both years (3.5% of all P. melanarius in 2021, and 10% in 2022). Across pitfall traps deployed on a single sampling date, up to 20% of P. melanarius had recently fed on R. maxima. Pterostichus melanarius predation on R. maxima was density dependent, and the half-life for detection of DNA from a single R. maxima larva in P. melanarius guts was 6.59 h. Overall, results confirm that (i) P. melanarius is a predator of R. maxima in the field, (ii) predation of R. maxima is dependent on R. maxima density, and (iii) field predation estimates are likely an underestimate due to the short detection half-life. These findings indicate P. melanarius may contribute to natural control of R. maxima in the field.

The fungal disease Rapid 'Ōhi'a Death (ROD) has caused extensive mortality in 'ōhi'a (Metrosideros polymorpha Gaudich) forests on Hawai'i Island since the mid-2010s. As the keystone species in native Hawaiian wet forests, the decimation of 'ōhi'a threatens the stability of Hawaiian forest communities. Invasive ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are the primary agents producing ROD inoculum and can directly transmit the pathogens as well. The most common management recommendation for ROD-infected trees is to fell and tarp. However, this is often logistically impractical and does not proactively suppress inoculum production. Alternatively, the semiochemical verbenone has proven effective in repelling ROD-associated beetles from standing 'ōhi'a and may have application in post-felling management. Across two 10-wk field and lab trials, we evaluated two semiochemical formulations, SPLAT Verb (10% verbenone) and SPLAT Beetle Guard (10% verbenone + 10% methyl salicylate), in reducing ambrosia beetle attack, emergence, and frass production when applied to felled ROD-Ceratocystis--infected 'ōhi'a. Verbenone alone significantly reduced beetle attacks and frass production, while verbenone + methyl salicylate also reduced attacks, outperforming verbenone alone by 37% in one trial, and reduced frass production and emergence. Beetle attacks subsided to near zero by week 10, presumably due to bolt desiccation, suggesting a single application may provide sufficient protection for the extent of a felled tree's host-suitability period. Semiochemical repellents may play a pivotal role in the multifaceted management approach needed to control ROD, and these findings validate and expand the emerging body of evidence establishing their efficacy in repelling beetles within the ROD pathosystem.

In the Great Lakes and Pacific Northwest regions of North America, maggots (Diptera: Anthomyiidae) threaten the production of dry bulb onion (Allium cepa L.). Onion maggot (Delia antiqua [Meigen]) is considered the primary Delia spp. pest in the Great Lakes, whereas seedcorn maggot (Delia platura [Meigen]) is considered most common in the Pacific Northwest. Bean seed maggot, Delia florilega (Zetterstedt), is also reported to infest onions, but has not been detected widely in these regions. Where these Delia spp. co-occur, D. platura/D. florilega are presumed to infest onions before D. antiqua, but this also has been poorly documented. To address these assumptions, larvae from infested onion plants were identified to species from 2022 to 2024. We hypothesized that D. antiqua and D. platura would be the predominant Delia spp. in the Great Lakes and Pacific Northwest, respectively, and that D. platura would infest onions before D. antiqua where they co-occur. Results indicated that D. antiqua was most common in the Great Lakes (87% of Delia spp.) and in eastern Oregon/western Idaho (USA) (79% of Delia spp.), but sample sizes were too small to make inferences about northern California and eastern Washington. Delia florilega was not detected in our study. Delia platura was most prevalent infesting onions early in spring, whereas D. antiqua was dominant in late spring and early summer. Our findings document Delia spp. composition and phenology in selected onion production regions and will inform regionally tailored monitoring and pest management strategies.

Previous research showed that the pheromone lure commercially formulated and produced for the exotic species Spodoptera exempta (Walker) also captured 2 native species, Spodoptera albula (Walker) and Spodoptera latifascia (Walker). This study expanded that work to identify the Spodoptera species that were attracted to lures specifically formulated for S. albula, Spodoptera cosmioides (Walker), Spodoptera eridania (Stoll in Cramer), Spodoptera exempta (Walker), Spodoptera exigua (Hübner), Spodoptera frugiperda (J. E. Smith), S. latifascia, Spodoptera litura (F.), and Spodoptera mauritia (Boisduval). In all trapping sites in Texas and Florida, S. exempta lures attracted S. latifascia and S. albula moths, sometimes at densities of over 80 moths per night. These lures, along with those designed for S. latifascia and S. albula, provided seasonal information for other Spodoptera species that are not routinely monitored. Lures for the South American species S. cosmioides consistently attracted the native non-pest Spodoptera dolichos (F.). Lures formulated for Spodoptera littoralis (Boisduval) from the Old World and S. litura from Asia also attracted native species. Trapping in a strawberry production area highlighted the possibility that S. latifascia and S. albula are potential pest species. Trials comparing different plastic-colored traps suggest that all white and green traps attracted fewer Spodoptera species moths than standard-colored Unitraps, which are green, yellow, and white.

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.

Phosphocholine cytidylyltransferase (CCT) and phosphoethanolamine cytidylyltransferase (ECT) are key enzymes in glycerophospholipid metabolism. They not only participate in the Kennedy pathway for phosphatidylcholine (PC) and phosphatidylethanolamine (PE) synthesis but also indirectly regulate triglyceride (TG) and cholesterol metabolism, contributing to lipid homeostasis. In this study, we revealed the roles of NlCCT and NlECT in the growth and lipid metabolism of Nilaparvata lugens. Despite conserved domains, RNAi knockdown of NlCCT or NlECT caused distinct phenotypes: both reduced survival, while dsNlECT also led to molting failure, increased body weight, and elevated TG levels. Lipidomics of dsNlECT-treated insects identified 86 significantly altered metabolites across nine lipid classes, mainly enriched in glycerophospholipid metabolism and TG biosynthesis pathways. RT-qPCR further validated 15 key metabolic enzyme genes correlated with these lipid changes. Notably, NlCCT expression was suppressed after NlECT knockdown, indicating close functional crosstalk. These results suggest that CCT and ECT coordinately regulate lipid homeostasis via a complex metabolic network in N. lugens. These findings highlight the critical roles of NlCCT and NlECT in regulating lipid metabolism in N. lugens, providing novel insights into the lipid metabolic network in insects and offering a theoretical foundation for the development of environmentally friendly pest control strategies targeting lipid metabolic pathways.

The alfalfa leafcutting bee (LCB) (Megachile rotundata Fabricius) is a solitary, managed pollinator widely used in North American agriculture to produce alfalfa and hybrid canola seed. Despite its economic importance, and known sensitivity to certain pesticides, little is known about the specific pesticide residues LCBs encounter during pollination, and toxicity data for this species remains limited. To determine what residues LCBs are commonly exposed to, we screened larval LCB provisions from nine alfalfa sites during pollination in southern Alberta for 69 pesticide residues. Eight residues amongst three classes of pesticides were detected including four fungicides (boscalid, cyprodinil, fludioxonil, and pyraclostrobin), three insecticides (chlorpyrifos, cyhalothrin lambda, and deltamethrin), and the herbicide Velpar (hexazinone). Using the residue data, we calculated site-specific hazard quotients (HQ) using Apis mellifera L. LD50s to provide context for exposure risk. Sites with residues from multiple pesticide classes tended to have higher-though not always significantly higher-HQs than sites with residues from only one class. These findings provide a regional profile for pesticide exposure for LCBs in southern Alberta and identifies compounds of potential concern for future toxicological testing and pollinator management.