There is a growing concern about the impact of environmental contamination by metals on insects owing to their biodiversity and important ecological roles.We investigated the neurobehavioral traits, cellular responses, and levels of metals in tissues of Nauphoeta cinerea nymphs exposed, separately and in ternary mixtures, to arsenic (15 and 7.5 mg/L), copper (15 and 7.5 mg/L), and zinc (100 and 50 µg/L), in drinking water for 35 consecutive days. Results showed that the diminutions in locomotor parameters (maximum speed, motility time, and distance traveled), motor and turning capabilities (path efficiency, turn angle, and body rotation) and the increase in anxiety-like behavior (total time freezing and freezing episodes) were more pronounced in individual metal exposure than triple metal mixtures groups. Barring zinc alone group, acetylcholinesterase activity decreased significantly in all the treatment groups compared to the control. The diminutions in glutathione level and antioxidant enzyme activities were partially attenuated in the fat body, midgut, and head of insects in the triple metal mixtures groups. Further, the levels of nitric oxide, hydrogen peroxide, lipid peroxidation, and reactive oxygen and nitrogen species were higher in individual metal exposed insects than the ternary mixture groups.The concentrations of arsenic, copper, and zinc in the fat body, midgut, and head of insects were significantly higher in individual metal exposure groups than the ternary metal mixtures groups. Collectively, the detrimental effects of elevated ecological concentrations of arsenic, copper, and zinc were more pronounced in insects exposed to individual metal than those in ternary mixtures groups.

Protected crops like greenhouses and indoor farms using light-emitting diodes (LEDs) allow precise control of light spectrum, intensity, and photoperiod for agronomic purposes.These artificial light conditions also influence insects and arachnids, including predators used in biological control. Despite growing interest, the effects of LEDs on predator behavior and control efficacy remain poorly understood. In microcosm experiments, we studied the locomotion and predation behaviors of the generalist predator Orius insidiosus against thrips (Frankliniella occidentalis) under different light spectra and intensities. We tested narrowband blue, green, and red spectra, 3 blue-red ratios, and a spectrum combining all 3 colors across a light-intensity gradient. Predators attacked prey under all lighting conditions, with 70% of individuals showing predatory behavior during observations. Spectral composition significantly influenced behaviors of interest, while light intensity had negligible effects. Narrowband spectra elicited the highest attack probabilities, but the mixed blue-red spectrum with a higher proportion of red light yielded the highest prey capture rates.The spectrum combining all 3 colors showed intermediate prey capture success. In complex environments with cucumber plants and 24-h artificial light sequences, prey capture probabilities followed similar trends to microcosm experiments. However, thrips survival rates remained similar across all lighting treatments. Our findings suggest that while lighting influences O. insidiosus behavior, this predator remains effective under various conditions, providing a foundation for lighting strategies that balance plant productivity with biological control.

Mating disruption is achieved by releasing synthetic pheromones into crop systems to disrupt natural mating behavior of targeted pests. Dispensers of synthetic pheromones are deployed in various crops with the intent of limiting males from finding females thereby reducing or delaying mating to lower pest populations over time. Codling moth (CM) (Cydia pomonella L.) and oriental fruit moth (OFM) (Grapholita molesta) (Busck) are worldwide pests of pome and stone fruits. We investigated the hypothesis that pupal exposure to species-specific sex pheromones affects subsequent mate-finding ability, mating behavior, and reproductive output of adult CM and OFM. Laboratory experiments revealed that pheromone exposure during the pupal stage significantly impacts CM reproductive output and mate-finding, whereas these effects were not observed with OFM. Our findings suggest that targeted deployment of pheromones to cause pupal exposure may enhance control of certain species such as CM.

Lateralization in mating behavior is increasingly recognized as a significant trait in insect species, yet its influence associated with gender, and sexual experience in Ostrinia furnacalis (Guenée) remains poorly understood. This study examines how lateralized mating behaviors, gender, and sexual experience interact to influence mating success and efficiency in O. furnacalis. We conducted controlled mating trials to assess how gender and sexual experience shape lateralized directional approaches (eg right- or left-biased) and turnings (eg 180° right- or left-biased) across the pre-copulatory, copulatory, and post-copulatory phases. Our results indicated that, in terms of gender, males were more likely to approach females, whereas females rarely initiated approaches, with both approaches each other simultaneously being infrequent. Both virgin and experienced males showed higher right-biased directional approaches than the front approaches to the females with more left-biased directional turns for successful intromissive copulation. Experienced males showed greater mating success than virgins. In contrast, experienced females exhibited lower mating success and longer post-copulatory interactions compared to virgin females, particularly duration of copulation. Post-copulatory interactions showed that antennal touching occurred more frequently in the experienced pairs. This study is the first to demonstrate the combined influence of gender and sexual experience on lateralized mating dynamics, with male courtship behaviors linked to learning processes. The results indicate that sexual experience, potentially involving learning and memory processes, significantly enhances mating efficiency and fitness in O. furnacalis. This research provides a more nuanced understanding of lateralized mating behaviors in O. furnacalis, with implications for refining pest management strategies in agricultural environments.

Graphical Abstract

The mealybug, Hypogeococcus pungens Granara de Willink (Hemiptera: Pseudococcidae), was released in Australia as a biological control agent for Harrisia martinii (Labour.) Britton (Cactaceae) in 1975. Although the mealybug successfully established in all released locations, its impact has been variable among regions, possibly as a result of climatic differences. Life-history traits (settling time, survival, development time, female reproduction, adult longevity) were compared at 6 constant temperatures (15 to 40 °C) in the laboratory. The mealybug settled on H. martinii at all temperatures tested, but at 15 °C and 40 °C, insects failed to develop and died. Temperature affected female size, fecundity, and integrated performance, all of which were highest at 25 °C. A linear model that fitted temperature to development time indicated a lower developmental threshold of 14.5 °C for both male and female mealybugs. CLIMEX models were developed for the mealybug and its host, H. martinii, and used to investigate the suitability of different regions of Australia, where H. martinii occurs for Hy. pungens. The Hy. pungens CLIMEX model suggests that cold stress limits mealybug growth in southern Queensland and that mealybug performance will vary between regions based on local temperatures. Locations with extreme low winter and extreme high summer temperatures are likely to have the most constrained populations. This may account for the observed differences in the effectiveness of Hy. pungens as a biological control agent at locations within the established range of H. martini in Australia.

In 2007 to 2008, I assessed the effects of ethanol release rate (dose) on trap catches of bark and woodboring beetles, and associated species of predators, in 6 experiments in north-central Georgia. Multiple-funnel traps were baited with ethanol alone or co-baited with α-pinene (with or without the bark beetle pheromones ipsenol and ipsdienol). The following species of bark and ambrosia beetles exhibited a positive dose-dependent response to ethanol, regardless of co-baits: Corthylus columbianus Hopkins, Dryoxylon onoharaense (Murayama), Hylastes porculus Erichson, Hylastes salebrosus Eichhoff, Hylobius pales (Herbst), Monarthrum fasciatum (Say), Orthotomicus caelatus (Eichhoff), Xyleborinus saxesenii (Ratzeburg), Xyleborus species, and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae). Hylastes tenuis Eichhoff (Coleoptera: Curculionidae) exhibited a positive dose-dependent response to ethanol alone but not when traps were co-baited with α-pinene, or α-pinene and bark beetle pheromones. A consistent negative dose-dependent response was exhibited by Ips grandicollis (Eichhoff) whereas results with Ips avulsus (Eichhoff) and Dendroctonus terebrans (Olivier) (Coleoptera: Curculionidae) were variable. Longhorn beetles were unaffected by ethanol dose except for Curius dentatus Newman (Coleoptera: Cerambycidae), which exhibited a positive dose-dependent response to ethanol.Three species of predators exhibited positive dose-dependent responses to ethanol: Temnoscheila virescens (F.) (Coleoptera: Trogossitidae), Platysoma parallelum (Say) (Coleoptera: Histeridae), and Lasconotus species (Coleoptera: Zopheridae). Ethanol is a key kairomone for many species of bark and woodboring beetles.

In tropical environments, insect prey face high predation rates due to the diverse interspecific interactions driven by various environmental factors. However, a detailed understanding of how these factors interact to influence predation rate remains limited.This complexity increases with the presence of both native and nonnative predators, yet no comprehensive assessment has been conducted. In this study, we used the pupae of the widely distributed fruit fly Bactrocera dorsalis to examine how 8 tropical environmental factors affect its predation rate. Principal component analysis identified 3 principal components (PCs) that collectively explain 78.86% of the variance in the influence of these environmental factors: PC1 accounted for 49.62%, PC2 for 15.59%, and PC3 for 12.65%. PC1 was strongly influenced by patch density (loading: 0.87) and altitude (loading: –0.90), with communalities of 77.8% and 82.3%, respectively. PC2 was primarily driven by native predator diversity (loading: 0.90), with the highest communality (84.1%). PC3 was characterized by temperature (loading: 0.65) and humidity (loading: 0.70), with communalities of 81.2% and 81.8%, respectively. Although no individual PC had a significant effect on predation rate, the interaction between PC1 and PC2 was highly significant, indicating a strong combined effect.This interaction likely results from the way altitude and human disturbance contribute to habitat fragmentation, which in turn affects native predator diversity and alters the predation rate for B. dorsalis.These findings offer valuable insights into the interaction between B. dorsalis and its predators, as well as into the effectiveness of potential control strategies involving predators.

In grassland ecosystems, oil and gas production areas require vegetation reclamations once extractions are completed. These reclamations take years to accomplish and may appear similar to the surrounding undeveloped grasslands. To test whether reclaimed oil/gas pads successfully recover ecological communities, we collected and utilized carabid beetles (Coleoptera: Carabidae) as bioindicators of reclamation success. We compared carabid beetle communities on well pad reclamations and within undisturbed native prairie 50 m and 150 m from the well pad reclaim edges. Overall, we found lower carabid richness and abundance in native prairie at the 150-m distance compared to the well pad reclaims, with the 50 m distance generally falling between the two. The differences in carabid communities likely reflect previously documented differences in vegetation types and structure within the reclaimed well pads that have persisted for decades after reclamation. These reclaimed habitats may be acting as “islands” for certain carabid species, representing population sources or sinks that likely influence carabid dynamics within the adjacent native prairie. These findings demonstrate a long-term signature of development disturbance in the landscape.

Intercropping has the potential to enhance crop yields by modifying the farmland ecosystem. However, its influence on ground-dwelling arthropod communities, especially in disturbance-sensitive environments, such as karst areas, remains inadequately understood.To address this knowledge gap, we conducted a study from April to September 2023, in a karst area to evaluate the impacts of tobacco–soybean intercropping on grounddwelling arthropods and soil properties. Trapping methods were used to examine arthropod communities under 5 crop planting schemes: tobacco monoculture (CK1), soybean monoculture (CK2), soybean ridge and furrow intercropping (T1), soybean single-sided ridge intercropping (T2), and strip intercropping with alternate soybean and tobacco furrows (T3). Formicidae were the predominant taxa across all planting schemes, with more shared taxa than unique taxa among the planting schemes. Arthropod community composition was stable among the planting schemes, but notable variation was observed among tobacco growth stages. Although intercropping schemes did not significantly impact arthropod density and diversity, these metrics were lower during the seedling stage compared with other growth stages. The densities of herbivores and detritivores under CK2 were significantly higher than those observed under the other planting schemes. Predator and omnivore densities were not affected by the intercropping scheme. Total phosphorus content and soil compaction were critical soil properties that influenced arthropod communities, suggesting that these variables play a crucial role in shaping the trophic structure of the community under intercropping regimes. These findings highlight the potential for optimization of intercropping strategies to enhance ground-dwelling arthropod biodiversity and promote sustainable agricultural practices in karst regions.

Graphical Abstract

Increasing sustainable productive activities to provide food, fiber, and energy is a global necessity for an increasingly populated planet. However, managing productive landscapes requires integrative approaches in which changes in diversity, microhabitat effects and managing conditions are assessed. We analyzed patterns of arthropod diversity, composition, and functional guilds in response to changes in canopy structure (solar radiation, geometry, and openness) in sun and shade coffee plantations in a coffee-producing landscapes of the northern Andes. We found that the response of the arthropod community varied according to the variables analyzed. On the one hand, we found that sun coffee plantations have higher arthropod richness and diversity. However, shaded coffee plantations show higher abundance and biomass values. Similarly, when the arthropod community was separated by functional guilds, a positive effect of solar radiation was observed in shade coffee plantations. Our results suggest that sun coffee plantations are not necessarily an inhospitable environment for arthropod diversity but may be so in terms of ecosystem functions. We conclude that a wider range of variables should be included to get a clearer picture of which productive landscape designs may be best for conserving arthropod biodiversity and ecosystem functions in productive landscapes.

The invasive spotted lanternfly (Lycorma delicatula) poses a significant threat to the US grape and wine industry. Spotted lanternfly feeding affects crop yield and fruit quality while increasing production costs through the increased use of insecticides for its management. This insect has a broad host range with tree of heaven and grapevines being preferred hosts. Although spotted lanternfly can develop when feeding solely on grapevines, the extent to which different grape cultivars support its survival and reproduction is less clear. We investigated the effect of grapevines and tree of heaven diets on spotted lanternfly survival, development, and reproduction. We fed nymphs and adults on either single or mixed diets of tree of heaven and 4 grapevine cultivars: 'Cabernet Franc' (Vitis vinifera), ‘Chardonnay’ (V. vinifera), ‘Concord’ (V. labrusca), and 'Sugargate' (Muscadinia rotundifolia). We found that single Sugargate diets supported spotted lanternfly development only to the fourth-instar stage. The development time was consistent across diet treatments, but reproduction varied significantly. Spotted lanternfly fed exclusively on grapevines had limited reproductive capability, with only 2 out of 5 females in the Chardonnay treatment laying a single egg mass each, averaging 13 eggs. While spotted lanternflies fed on mixed diets or single tree of heaven laid an average of 2.53 egg masses and 89.7 eggs per female. In conclusion, some single grapevine diets support development to adulthood but reproduction is limited without tree of heaven. This suggests that reducing tree of heaven near vineyards could help growers manage spotted lanternfly populations and minimize crop damage.

Dung beetles provide key ecosystem services in pasture environments. In the Northeastern U.S., dairy is the largest agricultural sector and grass-based dairy production is increasing. Despite the importance of dung beetles as beneficial pasture insects, the consequences of changes in pasture habitat with more cattle out on pasture are not well understood, nor is dung beetle species composition known for several states in Northeastern U.S. The aims of this study were to investigate dung beetle diversity and community structure on dairy pastures across Vermont and North Country, New York, and identify relevant livestock management factors that influence these dynamics. Dung baited pitfall trapping and soil health analysis were conducted on 29 grazing dairy farms using different grazing strategies and parasite management.The results reveal an abundant and diverse dung beetle community; however, the population was dominated by individuals of introduced species of European origin, particularly Colobopterus erraticus (Linnaeus, 1758; Coleoptera; Scarabaeidae) which comprised 74% of beetles collected. Native dung beetle species abundance was lower in the Northeast Kingdom of VT. Species assemblage structure differed between management practices related to parasiticide use and grazing. The soil health outcomes bulk density (0 to 50 mm), total carbon, and total nitrogen were correlated with dung beetle biodiversity indices and grazing management. The results indicate that livestock management may influence dung beetle species assemblages and strategies to support biodiversity may support soil health and nutrient cycling in the Northeast.

Ecological risk assessment is a key component of the regulatory process required for registration of crop protection products around the world. The western honey bee (Apis mellifera) is the model organism for pesticide risk assessments for bees, but there are uncertainties over whether it is predictive of risks to other bees. Consequently, efforts are underway to develop test methodologies for other non-Apis bees. We conducted a semi-field colony-feeding study with Bombus impatiens colonies to develop a colony-level methodology for bumble bees. We exposed commercially available bumble bee colonies to diets consisting of 4 concentration treatments of dimethoate insecticide (0.05, 0.19, 0.75, and 3.0 mg a.i./L) via supplemental sugar solution for 6 wk and compared exposed colonies to untreated controls. Each treatment group had 10 replicate colonies, with 1 replicate per treatment group represented at each of the 10 study rural locations. We collected data on various colony-level endpoints including production of female reproductive (gyne) offspring, colony weight, foraging activity, and consumption of provisioned sugar solution. Our results indicated that the test design could be used to derive concentration–response relationships for several endpoints including the most sensitive, colony mass (No Observed Adverse Effect Concentration = 0.05 mg a.i./L). Overall, our study provides the foundation for a semi-field, colony-feeding study test design for bumble bees, thus adding to the growing body of studies that may be used to assess the protectiveness of the honey bee risk assessment framework for non-Apis bees exposed to pesticides.

Multiple pathogens have been identified in red imported fire ants (Solenopsis invicta Buren) in native and introduced ranges, but pathogens infecting black (Solenopsis richteri Forel) or S. invicta × S. richteri hybrids are less studied. Pathogens like Kneallhazia solenopsae (Knell, Allen & Hazard) and Solenopsis invicta virus 3 (SINV-3) negatively impact colony growth and survival and offer augmentative biocontrol potential. The objective of this work was to determine the geography and phenology of K. solenopsae, SINV-1, SINV-2, and SINV-3 pathogens within theTennessee hybrid-dominated populations. During 2015 to 2016, 62 fire ant-infested counties were gridded (12.1-by-12.1 km), and one colony sampled per grid in warm (July to October) and cool (January to April) periods. Fire ant species were determined by cuticular hydrocarbon and venom alkaloid analysis. Samples were evaluated for pathogens, parasitoids, and social form by molecular analysis. Ant frequencies were hybrid (74.1%), black (25.3%), and red (0.6%). Infection rates were low (9.5% and 1.3% in warm and cool periods, respectively). Parasite prevalence was 4.2% (SINV-1), 1.3% (K. solenopsae), 0.9% (SINV-3), 0.1% (SINV-2), and 0.1% (Pseudacteon). Hybrid colony infection rates were higher (82.2%) than black and red (17.8%) colonies. Polygyne colonies were infrequent (n = 6 of 99) but were more frequently infected (66.7%) than monogyne (11.8%). The most widely distributed pathogen was SINV-1. Higher elevations may negatively influence SINV-1 range expansion. Higher hybridity values (ie more red-like) increased viral infection likelihood, but not Kneallhazia infection. Parasite prevalence was low in Tennessee hybrid-dominated monogyne populations, which may limit their impact on fire ant populations.

The soybean looper, Chrysodeixis includens (F.) (Lepidoptera: Noctuidae), is widely distributed throughout North and South America. It appears on important crop hosts with mixed populations of other looper species, especially the cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae). One of the earliest attempts to distinguish between the 2 species was to examine the legs of caterpillars, and those that possessed “black” legs were considered soybean loopers. However, it was demonstrated that this characteristic was variable and not under simple genetic expression. We examined 3 different environmental factors (temperature, light duration, and rearing density) to determine if these had an impact on the development of dark coloration on soybean looper legs. Larvae were exposed to 5 distinct levels of each environmental variable. We found that all 3 factors impacted the amount of dark coloration in the legs. Larvae reared at the coldest temperature and most light displayed darker-colored legs as early as the third instar of larval development. As larval rearing density increased, dark coloration on legs also increased, but this was not apparent until the fifth instar of larval development.There was a general trend for pupal weight to decrease and days to pupation to increase as the percentage of darkness on soybean loopers' legs increased within the various treatments of the study. Overall, dark leg coloration was largely dependent on environment and an apparent fitness cost was associated with larvae exhibiting darker legs within the various rearing conditions examined.

Predatory soil arthropods are under-represented in insecticide toxicity studies, severely limiting our understanding of how insecticides affect soil-invertebrate communities in agroecosystems. As a step toward addressing this issue, we conducted novel acute oral, topical, and soil-based toxicity assays on 9 ground beetle species (Coleopetera: Carabidae) in response to the neonicotinoid insecticides clothianidin, thiamethoxam, and imidacloprid. From these assays, we calculated 24 h TD₅₀, TC₅₀, LD₅₀, and LC₅₀ values, measured 24 h feeding activity, and recorded beetle survival for 7 d after exposure. Field-realistic oral, topical, or soil-based exposure to neonicotinoids rarely led to acute (<24 h) beetle mortality. Field-realistic topical and oral exposure of multiple tested species did, however, lead to significant sublethal effects—changes to mobility and feeding behavior—and decreased week-long survival. Under field conditions, carabids exposed to neonicotinoid sprays or contaminated food will be at higher risk of mortality from other factors (eg predation and starvation) which may affect their ability to contribute to biocontrol in agroecosystems. Similar toxicity assays with other carabid species, immature life stages, and additional taxa of predatory soil arthropods will further improve our understanding of how these insecticides affect soil-invertebrate communities in agroecosystems.

Variation in dark coloration due to melanin, i.e., melanism, in insects is often phenotypically plastic and adaptive. However, the pigment melanin and/or components of the melanin synthesis pathway, have many functions in insects beyond just coloration, such as roles in immune defense and cuticular hardening. For these reasons, melanism responses may sometimes be complicated, particularly if melanin-based coloration trades off with other melanin-based functions; such trade-offs may be related to resource availability.We manipulated the temperature and density (number of beetles per bean) of cowpea weevils, Callosobruchus maculatus (Fabricus) (Coleoptera: Chrysomelidae) during the larval and pupal period and found both variables affected the coloration and size (measured as area of elytra) of the emerging adults. Lower temperatures produced darker and larger beetles in both sexes, with females also being darker than males. Increased numbers of beetles per bean reduced both the size and darkness of the beetles.The effects of temperature on melanism are consistent with the adaptive thermal melanism hypothesis while the effects of per-bean density on melanism may reflect resource-based trade-offs. However, both effects were modest and left considerable variation in color unexplained.

Herbivorous insects can have their reproductive potential influenced by the quality and species of host plants they feed upon. The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive pest of ash trees (Fraxinus spp.) within its introduced range. As adults, EAB must feed upon foliage to sexually mature. We compared the influence of 4 North American ash species on EAB via foliage feeding to assess impacts on female lifespan and reproductive metrics. We fed 136 female EAB, 34 in each foliage group, either black, green, tropical, or white ash throughout their adult life. We performed daily inspections for adult mortality, oviposition, and egg hatching. We found that the mean female lifespan, fertility rate, and mean egg development time were not affected by the ash species. Potential and realized fecundity each increased with summed female group lifespan (days), but this rate differed among ash species. Consequently, there was a statistically significant interaction effect of the summed female group lifespan and the host foliage. Green ash-fed EAB laid (2.94 ± 0.86 eggs/female days) and hatched (1.67 ± 0.59 eggs/female days) the most eggs, more than double the rates of EAB feeding on black (1.39 ± 0.48 laid and 0.75 ± 0.30 hatched eggs/female days) and white (1.08 ± 0.35 laid and 0.65 ± 0.22 hatched eggs/female days) ash. Adults feeding on green ash resulted in the greatest EAB fecundity suggesting that the presence of green ash may promote population growth and provide a pathway to overwhelm other ash species nearby.

Four North American and one Asian ash species were planted in 2007 in 30 complete randomized blocks in a common garden in Ingham County, Michigan USA to evaluate host resistance and preference of emerald ash borer (EAB) (Agrilus planipennis Fairmaire), first detected in this area in 2003. Trees were protected from EAB colonization until 2012. We recorded current-year woodpecker holes and EAB adult exits on live trees annually from 2017 to 2022. Annual radial growth was quantified on increment cores from live trees and cross-sections from EAB-killed trees. Every Fraxinus nigra was killed by EAB by 2013. By August 2022, 63% of F. pennsylvanica, 12% of F. americana and 86% of F. chinensis trees had died. In contrast, F. quadrangulata trees were minimally colonized and remained healthy through 2022. Average (± SE) annual increment from 2007-2021 ranged from 2.65 ± 0.18 mm for F. quadrangulata to 4.61 ± 0.46 mm for F. chinensis. In an adjacent plantation planted in 2010, we assessed size, growth and EAB signs in 2022 on 12 live F. pennsylvanica and 12 Asian F. mandshurica. All F. mandshurica remained healthy with little evidence of EAB injury. Despite heavy EAB infestation, F. pennsylvanica radial growth in 2011 to 2022 remained relatively high. Results show F. nigra is highly preferred and vulnerable to EAB, followed by F. pennsylvanica, while F. americana is an intermediate host and F. quadrangulata is resistant. Of the 2 Asian species, F. mandshurica was resistant to EAB but F. chinensis trees were heavily colonized and most died.

Arbuscular mycorrhizal fungi are key components of the soil microbiota and are characterized by their symbiosis with terrestrial plants. In addition to providing nutrients to plants during symbiosis, arbuscular mycorrhizal fungi can enhance plant defenses against herbivorous insects and pathogens, including induced systemic resistance. Previous studies have demonstrated that Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) larvae perform better in maize plants colonized by arbuscular mycorrhizal fungi, which generally exhibit greater growth and higher nitrogen and phosphorus contents. However, these studies were limited to a small number of maize varieties. Additionally, prior research has not considered the host preference of S. frugiperda females for noncolonized versus arbuscular mycorrhizal fungi-colonized maize plants, although female choice can significantly influence progeny performance. In this study, we evaluated the effects of Rhizophagus irregularis (Blaszk, Wubet, Renker, & Buscot) C. Walker & A. Schüßler (Glomerales: Glomeraceae) inoculation on 4 maize inbred lines (CML 124, CML 343, CML 122, and CML 126) susceptible to S. frugiperda on female oviposition preference and larval performance of S. frugiperda. Overall, females preferred ovipositing on uncolonized seedlings to arbuscular mycorrhizal fungi-colonized seedlings, independent of the inbred lines. Larval performance was affected by inbred lines and arbuscular mycorrhizal fungi colonization. Larvae feeding on noncolonized maize seedlings exhibited significantly higher weights than those feeding on arbuscular mycorrhizal fungi-colonized seedlings. Among the inbred lines, larvae fed CML 122 performed better than those fed CML 126 and CML 343 seedlings. The weight of the larvae fed on CML 124 seedlings was similar to that of the larvae fed on CML 122, CML 126, and CML 343 seedlings.

Pollinator habitat can be planted on farms to enhance floral and nesting resources, and subsequently, pollinator populations.There is ample evidence linking such plantings to greater pollinator abundance on farms, but less is known about their effects on pollinator reproduction. We placed Bombus impatiens Cresson (Hymenoptera: Apidae) and Megachile rotundata (F.) (Hymenoptera: Megachilidae) nests out on 19 Mid-Atlantic farms in 2018, where half (n = 10) the farms had established wildflower plantings and half (n = 9) did not. Bombus impatiens nests were placed at each farm in spring and mid-summer and repeatedly weighed to capture colony growth. We quantified the relative production of reproductive castes and assessed parasitism rates by screening for conopid fly parasitism and Nosema spores within female workers. We also released M. rotundata cocoons at each farm in spring and collected new nests and emergent adult offspring over the next year, recording female weight as an indicator of reproductive potential and quantifying Nosema parasitism and parasitoid infection rates. Bombus impatiens nests gained less weight and contained female workers with Nosema spore loads over 150 times greater on farms with wildflower plantings. In contrast, M. rotundata female offspring weighed more on farms with wildflower plantings and marginally less on farms with honey bee hives. We conclude that wildflower plantings likely enhance reproduction in some species, but that they could also enhance microsporidian parasitism rates in susceptible bee species. It will be important to determine how wildflower planting benefits can be harnessed while minimizing parasitism in wild and managed bee species.

Perennial mixed forb and grassland habitats are crucial to conservation of pollinators and connectivity of habitats in intensely farmed landscapes.This study aims to understand the effects of land use on the pollinator community by describing bee abundance, species richness and community composition in perennial conservation grasslands and adjacent annual row crops located in west central Nebraska. In 2022 and 2023, we collected and identified bees via sticky traps at 4 locations (center and edge of adjacent grasslands and crop fields) at 6 replicated sites. We collected 1,768 specimens from sticky traps, resulting in 70 species within 28 genera. Halictidae accounted for 84% of the specimens collected. Bee abundance was influenced by the simple effects of land use (grassland vs. crops), edge adjacency, and the month and year of collection. Differences in bee abundance within a collection date were found mostly in early 2022 (May and June) and late 2023 (September), when the crop center location was generally the lowest, with some evidence for spillover of bees from the grassland into the crop edge during the early summer months. Bee species richness was affected only by month and was not significantly different by land use and edge adjacency. Bee community composition overlapped across the 4 locations, although there were significant dissimilarities between crop fields and grasslands. Surveys of the plant community revealed very low abundance of blooming stems and plant taxonomic richness at crop locations for all sampling periods, while grassland locations were comparatively high and varied over time. Plant communities showed no overlap between crop field and grassland locations. Overall, we found that conservation grasslands, while not seeded specifically with pollinator-attractive forbs, provide diverse resources to support wild bee communities in west central Nebraska; crop edges may also provide non-plant resources such as nesting sites and irrigation water. Going forward, better understanding pollinator species composition and resource utilization relative to land use characteristics and drought conditions will allow for better tailoring of conservation efforts and management strategies in Nebraska and across the larger region.

The study analyzed the population dynamics of aphids and their parasitoids in winter cereals in southern Brazil, using wavelet transform (WT) to detect patterns of periodicity and synchronization over a decade (2011 to 2020). The wavelet analysis revealed different patterns of population peaks between aphid species and their parasitoids. Aphids, such as Rhopalosiphum padi L., Sitobion avenae (Fabricius), Schizaphis graminum (Rondani), and Metopolophium dirhodum (Walker), showed varied peak frequencies, with M. dirhodum consistently exhibiting a shortening interval between outbreaks. In contrast, parasitoids maintained more-constant patterns, with peak frequencies predominantly around 12 mo. Cluster analysis identified 4 highly synchronized aphid-parasitoid pairs: S. graminum–Diaeretiella rapae (MacIntosh), R. padi–Aphidius platensis Brèthes, S. avenae–Aphidius uzbekistanicus Luzhetzki, and M. dirhodum–Aphidius rhopalosiphi De Stefani-Perez. The wavelet coherence (WC) showed significant correlations between the time series of these pairs, ranging from in-phase to anti-phase relationships over time. The results indicate that wavelet analysis is a viable tool for characterizing non-stationary time series, such as aphid and parasitoid populations. Understanding these dynamics and synchronization patterns can support integrated pest-management strategies, enabling more effective and sustainable agricultural interventions.

Spongy moth, Lymantria dispar Linnaeus (Lepidoptera: Erebidae), stands as a pervasive international threat, marked by its designation as one of the “world's 100 worst invasive species” by IUCN, owing to its voracious leaf-eating habits encompassing over 500 plant species. Its strong flight ability facilitates its spread and invasion. The present study aims to uncover differential gene expression, utilizing the Illumina Novaseq6000 sequencing platform for comprehensive transcriptome sequencing and bioinformatic analysis of total RNA extracted from larvae and pupae. Results revealed pivotal processes of protein functional structure conformation, transport, and signal transduction in functional gene annotation during the 2 developmental stages of spongy moth. 18 functional genes, namely, Distal-less (Dll), Wingless (Wg), Decapentaplegic (Dpp), Hedgehog (Hh), Cubitus interruptus (Ci), Patched (Ptc), Apterous (Ap), Serrate (Ser), Fringe (Fng), Achaete (Ac), Engrailed (En), Vestigial (Vg), Scute (Sc), Invected (Inv), Scalloped (Sd), Ultrabithorax (Ubx), Serum Response Factor (SRF), and Spalt-major, associated with wing development were identified, and their expression levels were meticulously assessed through real-time quantitative PCR (RT-qPCR) in 1st–6th instar larvae and male and female pupae wing discs. The results showed that 18 genes exhibited expression. Furthermore, the relative expression values of wing development-related genes were significantly higher in the pupae stage than in the larval stage.The relative expression values of male and female pupae were also significantly different.The RT-qPCR results were in general agreement with the results of transcriptome analysis. This study establishes a foundational understanding of the developmental mechanisms governing the formation of spongy moth wings.