First detections of nonnative insect species are often made by curious members of the public rather than by specialists or trained professionals. Passive surveillance is a crucial component of national biosecurity surveillance, highlighted by early detection case studies of several prominent nonnative arthropod pests (e.g., Asian longhorned beetle [ALB], Jorō spider, spotted lanternfly). These examples demonstrate that curiosity and the recognition of novelty in the natural world, along with enabling technology and systems, are a critical part of early detection and effective invasive species management. This is particularly impactful when dealing with conspicuous pests or for new and emerging nonnative species that have yet to be detected in a new location. Data from historical and recent accounts of first detections of ALB incursions and other invasive forest pests underscore the need to invest in passive surveillance reporting systems and fully integrate public observations into existing surveillance frameworks. New automated approaches streamline the assessment of public observations and can generate pest alerts to initiate a formal regulatory assessment. Biodiversity monitoring platforms, such as iNaturalist, provide a focal point for community engagement and aggregate verified public observations. Empowering proactive reporting of biological novelty provides needed support for early detection of invasive species. Embracing the public as active members of the surveillance community can be cost effective and lead to the greatest gains in the proactive management of invasive species around the world.

The impact of the programmatic use of larvicides for mosquito control on native stingless bees (e.g., Apidae, Meliponini) is a growing concern in Australia due to heightened conservation awareness and the growth of hobbyist stingless bee keeping. In Australia, the two most widely used mosquito larvicides are the bacterium Bacillus thuringiensis var. israelensis (Bti) and the insect hormone mimic methoprene (as S-methoprene). Each has a unique mode of action that could present a risk to stingless bees and other pollinators. Herein, we review the potential impacts of these larvicides on native Australian bees and conclude that their influence is mitigated by their low recommended field rates, poor environmental persistence, and the seasonal and intermittent nature of mosquito control applications. Moreover, evidence suggests that stingless bees may display a high physiological tolerance to Bti similar to that observed in honey bees (Apis mellifera), whose interactions with B. thuringiensis-based biopesticides are widely reported. In summary, neither Bti or methoprene is likely to pose a significant risk to the health of stingless bees or their nests. However, current knowledge is limited by regulatory testing requirements that only require the use of honey bees as toxicological models.To bridge this gap, we suggest that regulatory testing is expanded to include stingless bees and other nontarget insects.This is imperative for improving our understanding of the potential risks that these and other pesticides may pose to native pollinator conservation.

Graphical Abstract

Using a selection of native grass and forb seeds commonly seeded in local restoration projects, we conducted a field experiment to evaluate the effects of seed species, distance of seed patches from nests, and distance between patches on patterns of seed removal by Owyhee harvester ants, Pogonomyrmex salinus (Olsen) (Hymenoptera: Formicidae). To provide context for ants' seed preferences, we evaluated differences in handling time among seed species. In addition, we assessed the influences of cheatgrass, Bromus tectorum (L.) (Poales: Poaceae), and Sandberg bluegrass, Poa secunda (J. Presl) (Poales: Poaceae), cover on seed removal. We found significant differences in removal rates among seed species. In general, seeds placed closer to nests were more vulnerable to predation than those placed farther away, and seeds in closely spaced patches were more vulnerable than seeds in widely spaced patches. However, the strength of these effects differed by seed species. Differences in handling time among seed species may help to explain these findings; the protective effect of from-nest distance was weaker for species that required less time to transport. For 2 of the seed species, there was an interaction between the distance of seed patches from nests and the distance between patches such that the protective effect of distance between patches decreased as the distance from nests increased. Cheatgrass and bluegrass cover both had small protective effects on seeds. Taken together, these results offer insight into the spatial ecology of harvester ant foraging and may provide context for the successful implementation of restoration efforts where harvester ants are present.

Two species of Haploembia Ramburi (Oligotomidae: Embioptera), nonnative detritivores found in the western USA, display solitary tendencies, not typical for webspinners that usually share silk galleries. Reports from the 1960s based on native populations in Italy highlighted the impact of a gregarine that depressed male sterility and female survivorship in Haploembia solieri (Rambur). Sympatric asexual Haploembia tarsalis (Ross) lives a normal lifespan when parasitized, albeit suffering from reduced fecundity. Our goal is to characterize behavioral repertoires as individuals interact and to develop methods for future investigations focused on the impact of the little-known parasite. We quantified individual responses to conspecifics or other species in 10-min dyadic interactions and, in a 3-day trial, determined whether they aggregated when given dispersed resources. Replicated groups of four adult female H. solieri or H. tarsalis settled away from each other over the 3-day trials. In 10-min bouts of same or different species pairs, focal insects bolted back, retreated and attempted to escape when they encountered one another, especially when the opponent was H. tarsalis. Males courted conspecific females, but were dramatically repelled by H. tarsalis. Serving as a positive control, Oligotoma nigra (Hagen) (Oligotomidae) adult females paired with conspecifics displayed typical webspinner behaviors by sitting together, sharing silk. Haploembia solieri males did not respond negatively to O. nigra, not known to be parasitized by the gregarine, but did so when paired with H. tarsalis. Results align with the prediction that susceptibility to parasitism may have led to antisocial behaviors observed in two Haploembia species.

Termite mounds are a ubiquitous feature of savanna ecosystems, yet the mechanisms by which termites (Blattodea: Termitoidae) mitigate the challenges posed by seasonal drought and flooding through mound construction remain insufficiently explored. This study investigates the material properties, water retention capabilities, and resistance to raindrop penetration across three distinct layers of Globitermes sulphureus (Haviland, 1898) (Blattodea: Termitidae) nests. Our findings reveal a pronounced diversification and specialization of materials and functions across these layers. Specifically, the outer layer has decreased moisture permeability, the middle layer has enhanced resistance to water penetration, and the innermost layer has a high capacity for water retention. The integration of these functionally specialized layers provides a compelling evidence for explaining how these termites are able to adapt to the fluctuating environmental conditions characteristic of savanna ecosystems. Furthermore, this highlights the nest's buffering capability against environmental stressors.The complexity of this construction, marked by a level of self-organization rarely observed in the animal kingdom, underscores a significant instance of architectural ingenuity among non-human builders.

Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae) is an important egg parasitoid of the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). Methods for laboratory-rearing O. agrili have been developed but its mass-production depends on the continuous production and storage of freshly laid EAB eggs as well as diapaused parasitoid progeny (inside parasitized EAB eggs). The purpose of this study was to determine optimal environmental conditions for long-term storage of host eggs as well as diapaused parasitoid progeny. Fresh host eggs and diapaused parasitoid progeny were stored at two low storage temperatures (1.7 and 12.8 °C) and three levels of relative humidity (low ∼31%, medium ∼74%, and high ∼99.9%) for various length of time (15–270 days) and then evaluated for host egg suitability and the reproductive fitness of stored parasitoid progeny. EAB eggs were stored for approximately 30 days without significant reduction of their viability and suitability to O. agrili parasitism at low storage temperatures under high and medium relative humidity. Neither storage temperature or humidity had any significant effects on adult parasitoid emergence for storage durations of up to 270 days. When storage durations were over 120 days, however, both adult parasitoid longevity and fecundity declined approximately 20–30% across all temperature and humidity treatments. Relevance of findings to mass-production and storage of O. agrili for biocontrol is discussed.

Anastatus orientalisYang & Choi (Hymenoptera: Eupelmidae), an egg parasitoid of spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae), has been documented emerging from host eggs in both autumn and spring, at the beginning and end of the period that spotted lanternfly eggs are present in the field, suggesting parasitoid–host specificity and synchrony. This study was designed to test whether, under conditions that simulate native and introduced ranges of spotted lanternfly, (a) A. orientalis has 2 and only 2 generations per year, (b) A. orientalis adults sometimes emerge when only nontarget species would be available for parasitization, and (c) emerging parasitoid adults can parasitize unhatched host eggs in the spring. Parasitized spotted lanternfly eggs were collected in 2019 and 2020 from Beijing, China and in 2020 and 2021 from Yantai, China. They were shipped for laboratory study in growth chambers programmed to simulate temperature and daylength for collection locations in China and in the invaded range in Pennsylvania, United States. Anastatus orientalis had a flexible lifecycle depending on environmental conditions and possibly genetic makeup, with 1–3 generations per year, and parasitoid emergence was not always synchronous with host egg availability. Additionally, given the cooler temperatures in Pennsylvania, autumn parasitoid emergence was often delayed until late October or November, no progeny were produced, and parasitoid populations died out. Anastatus orientalis does not exhibit host synchrony characteristics that would make it a good candidate for a classical biological control program.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), commonly known as spotted-wing Drosophila (SWD), is an invasive insect pest threatening the economy of many small fruit farms in the Americas and Europe. Biological control using parasitoids is a promising strategy for improving the sustainable management of SWD. To use the parasitoids as biocontrol agents, recognizing and understanding the presence and preference of North American native parasitoids and their local adaptation is necessary. We conducted 2 season-long field explorations of North American native parasitoids of SWD during 2021 and 2022 at major blueberry-producing locations in southeast GA, USA. A total of 371 parasitoids of Drosophila were collected using fruit-baited sentinel traps and classified into 3 families: Figitidae, Pteromalidae, and Diapriidae. Leptopilina boulardi (Hymenoptera: Figitidae) and Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae) were the most abundant species. The abundance of parasitoids was higher during the peak blueberry ripening period through the end of the harvest season compared to all other phenological stages. Out of the North American native parasitoids of SWD that we collected, Pachycrepoideus vindemmiae successfully parasitized SWD in its natural habitat, and L. boulardi only parasitized SWD larvae at a low rate of 7% in the laboratory, but it failed to emerge from all the parasitized SWD. Ultimately, we found that the existing North American native parasitoids were inadequate to suppress the SWD in these locations. Planned intervention with the classical release of Asian native specialist parasitoids in addition to the existing SWD management approaches was deemed necessary in these areas.

We describe experiments that evaluated potential sex pheromone components for 6 North American click beetle species. In field trials in Illinois, South Carolina, North Carolina, and Virginia, male beetles of 6 species were strongly attracted to geranyl butyrate (Agriotes insanus Candèze), 5-methylhexyl (Z)-4-decenoate (Elater abruptus Say), 11-dodecenyl butyrate (Melanotus ignobilis Melsheimer), and limoniic acid (Gambrinus griseus [Palisot de Beauvois], G. rudis [Brown], and G. plebejus [Say]). Collection of E. abruptus in South Carolina represents a new state record. For each species, capture rates varied geographically and temporally, possibly due to differences in local population densities and regional phenology, or the efficiency of different trap designs or trap placement. Structural similarities were observed between the tested attractants and previously identified pheromones of closely related species. For example, males of A. insanus were attracted to geranyl butyrate, analogous to the terpenoid ester pheromones of a number of European congeners. The attractant for E. abruptus, 5-methylhexyl (Z)-4-decenoate, is an analog of the pheromone of its European congener E. ferrugineus L., and the attractant for M. ignobilis, 11-dodecenyl butyrate, is an analog of attractants of European and Asian congeners. Attraction of the 3 Gambrinus species to limoniic acid parallels recent reports of attraction of the congeners G. seminudus (Van Dyke) and G. ursinus (Van Dyke) to this compound, which was originally identified from closely related species of Limonius. Full identifications of additional sex pheromones for elaterid species should provide a more complete picture of the diversities/similarities of the semiochemicals mediating reproductive behaviors of this biologically diverse and taxonomically complex group.

Scarab beetles use pheromones and volatiles to search for their partners and host plants. The perception of these compounds occurs in the beetle antennae, particularly in the sensilla. Relatively few studies have morphologically and physiologically characterized the sensilla of scarab beetles. Cyclocephala barrerai Martínez is a beetle distributed in Mexico. Male beetles have larger antennal lamellae than females, and in both cases, the size of this structure is related to their weight. Previous studies have reported that both sexes are attracted to bacterial volatiles isolated from the female genital chambers. Female cuticular hydrocarbons may act as a sexual contact pheromone. However, antennal sensilla and their electrophysiological responses to behaviorally relevant compounds remain to be investigated. Here, we describe and report the types, allometric relationships, and functions of sensilla found in the lamellae of both C. barrerai sexes. Sensilla were identified, classified, measured, and counted to identify intra and intersexual relationships. The single sensillum recordings showed that plant volatiles, hydrocarbons, and heat stimulated receptor neurons. We identified 2 new types of sensilla basiconica in the scape. Males have more and larger antennal sensilla placodea IV, which specializes in detecting pheromones, plant volatiles, and heat. Females have a greater diversity of sensilla.

Batocera horsfieldi is the primary stemboring pest of timber forests and economic forests in China, belonging to the Coleoptera Cerambycidae. In this study, gas chromatography-mass spectrometry was used to analyze the volatile components in the supplementary feeding hosts and oviposition hosts of B. horsfieldi, and characteristic fingerprints were constructed. A total of 168 compounds were detected, primarily consisting of terpenes, hydrocarbons, and aldehydes, with 75, 23, and 14 compounds, respectively. Hierarchical cluster analysis and principal component analysis yielded consistent results. The similarity evaluation results showed that the similarity range between healthy poplar tree bark and healthy poplar leaves was the highest, reaching 0.953–0.98, and 10 common peaks were identified. The analysis of the correlation with climatic factors shows that most compounds are positively correlated with mean annual humidity, mean annual temperature, mean annual minimum temperature, and mean annual maximum temperature. Only caryophyllene and alpha-guaiene are negatively correlated with temperature-related climatic factors. Pathway analysis also reveals differences in the direct effects of different compounds. These analytical results provide a theoretical basis for further studying the selection mechanism of B. horsfieldi on hosts and offer theoretical guidance for identifying plant-derived attractants with biological activity.

Hibiscus mealybug, Nipaecoccus viridis (Newstead) (Hemiptera: Pseudococcidae), is a recent invasive pest of citrus and many other crops in Florida. Nipaecoccus viridis attacks all above ground parts of citrus trees and heavy infestation can cause leaf drop and premature abortion of developing fruits. We quantified greater captures of N. viridis in cardboard band traps on areas of citrus trees that were intentionally injured by mechanical rasping of epidermal tissues as compared with similar but uninjured citrus branches. Direct field collection of headspace volatiles from mechanically injured or intact citrus branches revealed both qualitative and quantitative differences. Certain volatiles (γ-terpinene, citronellal, citronellyl acetate, β-E-farnesene, α-humulene, and α-E-E-farnesene) were only present in samples from damaged citrus branches. Behavioral assays using a laboratory Y-tube olfactometer revealed attraction of N. viridis to volatiles associated with mechanical damage of citrus including synthetic β-ocimene, γ-terpinene, sabinene, isomers of farnesene, and citronellal when loaded into lures at either of 2 concentrations (0.01 or 0.1 µg/µl). Subsequent field trapping experiments confirmed increased captures of various life stages of N. viridis in cardboard band traps baited with a 10.0 µg/µl concentration of farnesene:ocimene:sabinene blend (in 7:13:17 ratio), as well as those releasing either farnesene or ocimene alone at this same concentration, as compared with the mineral oil (diluent) negative control. Our results indicate that common plant related terpenes released by citrus following mechanical damage may be useful for development of an effective monitoring trap for N. viridis.

Graphical Abstract

Orchard bees of the genus Osmia Panzer are important pollinators of fruit trees in various regions of the world, with some species commercially available in the United States and Europe. In addition to their pollination services, Osmia lignaria, Osmia cornifrons, Osmia bicornis, and Osmia cornuta have been identified as potential model species for solitary bees in pesticide risk assessment and have been used for the development of new methods to test acute lethal effects via contact and oral routes of exposure. Our goal was to expand the available methodology to characterize the toxicity of pesticides for these solitary bees through a chronic oral test for adult bees. Chronic oral toxicity of pesticides to orchard bees has been reported, but methods differ among research groups. In our study, O. lignaria, O. cornifrons, O. bicornis, and O. cornuta female bees had access to sucrose solution ad libitum in separate, species-specific 10-day tests. Mean body mass, mean daily consumption, and survival differed among the studied bee species. The dose–response test design was validated with dimethoate, a reference toxic compound, and chronic toxicity endpoints were estimated for the 4 Osmia species. The median lethal daily doses normalized by weight for O. lignaria, O. bicornis, O. cornuta, and O. cornifrons were within the same order of magnitude at 0.23, 0.26, 0.49, and 0.61 µg dimethoate/g bee/day, respectively. The methodology described here was aligned as much as possible with the available honey bee and bumble bee standard methods to facilitate the comparison of chronic toxicity profiles among bee species.

Management solutions for waste in southern Thailand, such as fly larvae, are tested in a laboratory using different substrates and wastes from the Thai agricultural sector. The nutritional content of the immature stages of Musca domestica Linnaeus (Diptera: Muscidae) and Hermetia illucens (Linnaeus) (Diptera: Stratiomyidae) larvae, especially their protein and fat contents, makes them a potential animal feed. Laboratory strains of M. domestica and H. illucens were reared on selected substrates to examine how diet influenced their performance and nutritional composition. Waste from aquaculture, vegetables, and fruits in southern Thailand was examined for larval diet and showed promise as a rearing substrate for these insects. Musca domestica larvae reared on fishery waste achieved the highest larval weight and fat content, whereas H. illucens larvae reared on an aquaculture waste diet had the highest protein content.These findings imply aquaculture waste could be the best choice for large-scale fly larvae production, particularly as a protein feed additive.

Nitidulid beetles (Coleoptera: Nitidulidae), the overland vectors of the Bretziella fagacearum fungus that causes oak wilt, were monitored in infection centers in Quercus rubra stands in northern Michigan, USA using baited, wind-oriented traps for 2 years. First nitidulid captures, accounting for <1.5% of total annual captures, occurred in late April in both years (<50 cumulative degree days [DDs]; base 10°C). A total of 1,188 and 735 beetles representing 19 and 18 species were captured in 2018 (18 traps; 3 sites) and 2019 (16 traps; 4 sites), respectively. Ground traps (1.5 m high) captured more beetles and species than traps on canopy branches of red oaks. Most nitidulids (81–86%) were captured in May and June, but frequent precipitation and cool spring temperatures extended activity into early July in 2019. In 2018, 336 beetles representing 12 species were screened for B. fagacearum spores, but only 20 beetles from 4 species bore viable spores. Mycelial mats on red oaks killed were 4-fold more abundant in 2019 than in 2018. Of the 225 beetles screened in 2019, 56 beetles representing 6 species had viable spores. Nearly all (96%) spore-bearing beetles in both years were captured in late May or June. In bimonthly xylem samples collected from healthy trees, large earlywood vessels, presumably more vulnerable to infection than latewood, were present from May to June in 2018 and until early July in 2019. Results are consistent with mid-May to mid-July high-risk periods designated in current state and regional guidelines for oak wilt management.

The increase in extreme climate events in recent years has been considered as an important factor affecting forest pests. Understanding the responses of forest pests to climate is helpful for revealing the trends in forest pest dynamics and proposing effective control measures. In this study, the relationship between the dynamics of all forest pests, independent forest diseases, and forest insect pests with the climate was evaluated in China, and the corresponding differences among forest pests, diseases and insect pests were assessed. Based on cross-wavelet transform and wavelet coherence analysis, the influences of teleconnection factors on the relationship between climate and forest pests were quantitatively analyzed to determine the roles of these factors. The results indicate that (i) three types of disasters in most parts of China have decreased from 1979 to 2019, while forest pests and forest insect pests in the southwestern region have increased; (ii) the relationship among Forest Pest Occurrence Area Rate and climate factors such as the Multivariate ENSO index, Southern Oscillation index, Arctic Oscillation (AO), Atlantic Multidecadal Oscillation (AMO), and Sunspot is more significant; (iii) the cycle is short in most regions, with oscillations in 2–4 years bands being the main variation periods of disasters in East, Central, and South China; (iv) There is a significant correlation between climate and disasters in the periods of 2–4 or 8–10 years. The AO, AMO, and Sunspot were important driving factors affecting the relationship between climate and disasters. Specifically, the Sunspot had the greatest impact among these factors.

The maize crop is highly susceptible to damage caused by its primary pests, which poses considerable challenges in manually identifying and controlling them at various larval developmental stages. To mitigate this issue, we propose an automated classification system aimed at identifying the different larval developmental stages of 23 instars of 4 major lepidopteran pests: the Asian corn borer, Ostrinia furnacalis (Guenée; Lepidoptera: Crambidae), the fall armyworm, Spodoptera frugiperda (J.E. Smith; Lepidoptera: Noctuidae), the oriental armyworm, Mythimna separata (Walker; Lepidoptera: Noctuidae), and the tobacco cutworm, Spodoptera litura (Fabricius; Lepidoptera: Noctuidae). Employing 5 distinct Convolutional Neural Network architectures—Convnext, Densenet121, Efficientnetv2, Mobilenet, and Resnet—we aimed to automate the process of identifying these larval developmental stages. Each model underwent fine-tuning using 2 different optimizers: stochastic gradient descent with momentum and adaptive moment estimation (Adam). Among the array of models tested, Densenet121, coupled with the Adam optimizer, exhibited the highest classification accuracy, achieving an impressive 96.65%. The configuration performed well in identifying the larval development stages of all 4 pests, with precision, recall, and F1 score evaluation indicators reaching 98.71%, 98.66%, and 98.66%, respectively. Notably, the model was ultimately tested in a natural field environment, demonstrating that Adam_Densenet121 model achieved an accuracy of 90% in identifying the 23 instars of the 4 pests. The application of transfer learning methodology showcased its effectiveness in automating the identification of larval developmental stages, underscoring promising implications for precision-integrated pest management strategies in agriculture.

Insects that evolved in mesic regions may have difficulty establishing in xeric regions. Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) was introduced into drier western North America from mesic eastern North America while Rhagoletis indifferens Curran is native to western North America. Here, we predicted that R. indifferens survives water deprivation longer than R. pomonella, as R. indifferens is more abundant than R. pomonella in dry central Washington (WA) State, USA. Sweet and bitter cherry-origin R. indifferens and apple- and hawthorn-origin R. pomonella from xeric central or mesic western WA were provided water throughout or were water-deprived at 2–4 and 14–18 d old and held at 20°C or 30/31°C and daily survival recorded. At 20°C and 30°C, western WA apple-origin R. pomonella provided water survived longer than sweet cherry-origin R. indifferens. When water-deprived, however, 2–4 d old R. indifferens, although smaller, survived significantly longer than western WA apple-origin R. pomonella of the same age. This was also generally true for 14–18 d old flies, although differences were less often significant. Central WA large-thorn hawthorn-origin R. pomonella survived water deprivation significantly longer than western WA apple-origin R. pomonella, and as long as R. indifferens. Water-deprived flies of both species survived longer at 20°C than 30/31°C. Survival analyses suggest that low water availability rather than high temperature contributes to lower R. pomonella than R. indifferens abundances in central WA, with R. pomonella populations in that region differing from western WA R. pomonella with respect to tolerance of xeric climates.

Temperature is an elementary component in mathematical models for predicting the biotic potential of insects. In this study, the objective was to evaluate the impact of different constant temperatures of 8, 10, 15, 20, 25, 30, and 32°C on the biological parameters, lower temperature thresholds (TT), and estimating the number of annual generations (NAG) of Rachiplusia nu and Chrysodeixis includens, both pests associated with the soybean crop in Brazil. There was no development of the immature stages of R. nu at 8°C, as was also found for C. includens at 8 and 10°C. However, at 10°C all stages of R. nu developed. In general, temperatures of 20 and 25°C were the most suitable for the development of R. nu and C. includens, providing egg to adult viability of over 60% and the highest total fecundities. However, the temperature of 32°C negatively affected the parameters of the fertility life table. Rachiplusia nu showed the lowest TT (eggs: 4.9°C; larvae: 10.8°C; pupa: 14.1°C; and egg to adult: 8.9°C) when compared with C. includens (eggs: 7.5°C; larvae: 15.3°C; pupa: 16.1°C; and egg to adult: 11.3°C). Based on TT values, the NAG varied from 3.9 in cold regions to 7.5 in warm regions. However, for C. includens, we can infer that the species can reach up to 8.8 generations in warm regions. The results of the present study are important for understanding the occurrence of R. nu and C. includens in field conditions and can help with the implications of management strategies.

Changing climate patterns will likely affect insect pressure on many agricultural crops. Mild winters may decrease the number of insects that experience reduced fecundity or that are killed during hard freezes. This may result in larger populations in subsequent years and allow for range expansion. Direct effects from pests are compounded by indirect effects, such as crop damage resulting from insect-vectored diseases. Corn flea beetle (Chaetocnema pulicaria) infestations have both direct and indirect effects on crops. This beetle is a pest on all types of corn in the United States, including sweet corn and grain corn (sometimes referred to as dent corn). It is responsible for damage to plant foliage and also serves as the primary overwintering vector for Pantoea stewartii bacterium, which causes Stewart's Wilt, a disease that can severely impact the health and productivity of corn. Evidence suggests that warmer winters will contribute to a geographic range expansion for the corn flea beetle. Here we show the projected northward expansion of economically damaging crop losses caused by Stewart's Wilt: (A) from 1980 to 2011, (B) projected by mid-century, and (C) projected by end-century. Our work suggests that climate change and associated increasing winter temperatures in the United States will lead to a dramatic increase in the probability of severe damage from corn flea beetle across the United States, including the Corn Belt. Predicted increases in pest and disease pressure will have negative ramifications for corn production and are likely to exacerbate issues associated with specific management tactics, such as pesticide application.

Atmospheric and soil nitrogen levels are increasing across the world. Nitrogen addition can alter vegetative and flower traits, including flowering phenology, floral production, and flower morphology, and the quantity and quality of floral rewards such as nectar. However, it is not well understood if and how these changes in floral traits will affect foraging preferences and pollination by different pollinator species. We hypothesized that honey bees (Apis mellifera) would exhibit a preference for plants with increased numbers of flowers, while bumble bees (Bombus spp.) would exhibit a preference for plants with increased nectar production as a result of soil nitrogen addition. A 2-yr field experiment was conducted to investigate the effects of varying nitrogen supply levels (e.g., 0, 4, 8 kg N ha^–1 yr^–1 of N0, N4, and N8) on the vegetative and floral traits of a perennial plant (Saussurea nigrescens), as well as the visitation rates of introduced managed honey bees (A. mellifera) and the native wild bumble bees. The results showed that adding nitrogen increased the number of flowers and nectar production. However, honey bees and bumble bees were responding to different floral resources that induced by nitrogen addition, with honey bees prioritizing the number of flowers and bumble bees prioritizing nectar quantity. The findings shed new light on how plants and pollinators interact when nitrogen is added, as well as how pollinator communities will be affected in the future.

Red maples (Acer rubrum L.; Sapindales: Sapindaceae) are common shade trees well known for their stunning autumn foliage and fast growth. They are a popular choice for landscapes, parks, and public places across the United States. Flatheaded borer species in the genus Chrysobothris (Coleoptera: Buprestidae) are some of the most damaging insects in red maple production, with attacks being most common on stressed and newly transplanted trees. In nurseries, red maples routinely experience flatheaded borer attacks, while the Freeman maple hybrid ‘Autumn Blaze’ has been reported as potentially resistant to flatheaded borers. In this study, traits of three borer susceptible red maple cultivars (‘Brandywine’, ‘Sun Valley’, and ‘October Glory’) were compared against a potentially resistant Freeman maple hybrid cultivar for baseline differences as well as differences under the stress of a foliar herbicide application Scythe (pelargonic acid 57%). Morphological, physiological, and biochemical traits of the red maple cultivars were evaluated and contrasted with the hybrid to identify traits related with borer resistance. Under normal conditions, the hybrid maple exhibited faster growth, greater concentrations of sulfur, and lower concentrations of zinc and flavonoids in leaf tissues compared to red maples. The herbicide stress treatment resulted in greater nitrogen and sulfur concentrations in hybrid foliage, but less chlorophyll, flavonoid, and zinc concentrations compared to the red maple cultivars. Field trials validated borer preference for red maples over the hybrid. Traits associated with the hybrid warrant additional study if an understanding of the causal relationship with borer resistance is to be achieved.

Psyllids (Hemiptera: Psylloidea) are herbivores that feed and reproduce on narrow subsets of hosts within a few related genera. During surveys of Solanum umbelliferum (Eschsch) (Solanaceae), we collected multiple life stages of Bactericera maculipennis (Crawford), a species exclusively associated with bindweeds (Convolvulaceae). We hypothesized that B. maculipennis has expanded its host range to include this solanaceous host. To test this, we quantified egg to adult development time on S. umbelliferum, 2 other solanaceous hosts, and Convolvulus arvensis L., the most suitable host for B. maculipennis in North America. B. maculipennis failed to develop on additional solanaceous hosts but developed significantly faster on S. umbelliferum than on C. arvensis. We also sampled for B. maculipennis at 27 S. umbelliferum populations and collected 24 individuals directly from S. umbelliferum plants. We confirmed all individuals are B. maculipennis and found that 10/24 were infected with the plant pathogen ‘Candidatus Liberibacter solanacearum’ (CLso), which is transmitted by the potato psyllid, B. cockerelli (Šulc). Half of infected individuals harbored CLso haplotype B, which is dominant in crops, but rare in S. umbelliferum. The other 50% harbored CLso haplotype Sumb2, previously documented in S. umbelliferum, but never in crops. Our results suggest that the host range of B. maculipennis has expanded to include a key wild host plant of B. cockerelli. This may create opportunities for exchange of multiple haplotypes of CLso between these 2 species, possibly facilitating the emergence of CLso variants as pathogens of plants in the Convolvulaceae.

Mason bees, subgenus Osmia Panzer (Hymenoptera: Megachilidae), are economically and ecologically significant pollinators. In eastern North America, the rapid spread of 2 non-native species from Asia, Osmia cornifrons Radoszkowski and Osmia taurus Smith, has coincided with declines in native Osmia populations, raising concern about the effects of further exotic arrivals. Here we investigate the recent establishment in British Columbia, Canada of the European orchard bee, Osmia cornuta Latreille, previously thought to be limited to Europe and its periphery. We document O. cornuta records ranging more than 170 km, including sightings of live adults and the discovery of a multigenerational nest with hundreds of cocoons. We tested whether these cocoons could be discriminated from other Osmia species by training a machine learning classifier on features extracted from images. The best performing model could not reliably discriminate cocoons by species, raising the possibility O. cornuta could be inadvertently intermingled in future commercial shipments. Recent occurrence records of O. cornifrons and O. taurus were spatially isolated, suggesting ongoing anthropogenic dispersal of these species. We predicted the suitability of North American habitats for O. cornuta by estimating its native climate niche. This analysis indicated broad regions of the Pacific Northwest and eastern North America contain potentially suitable habitat. Our findings document the establishment of O. cornuta in North America and the potential for its expansion. Our study demonstrates the utility of accessible biodiversity data archives and public observation programs in tracking non-native species spread and highlights the need for future monitoring of exotic Osmia.

Body size is an important functional trait to animals. Caste division of eusocial insects can exert a profound influence on their interactions with environment. We investigate the intra-specific variation of body size between caste within Odontotermes formosanus (Shiraki) (Blattodea: Termitidae), the most common and widely distributed termite species in Taiwan Island. By utilizing specimens from the NCHU Termite Collection and WorldClim data, we describe the body size distribution pattern of O. formosanus on two castes, worker and alate, and relationship with climatic factors is examined. The body size of workers is positively correlated with latitude and elevation. The body size of alates does not correlate with latitude but is positively correlated with elevation. Temperature factors negatively affect the body size of both castes. Precipitation has a positive effect on the body size of alates and no effect on workers. Additionally, humidity and temperature fluctuations over time have divergent effects on the body size of alates and workers. The results provide evidence of trait evolution decoupling at the intraspecific level, which may be shaped by climatic factors.

The monarch butterfly (Danaus plexippus) is a vagile species that undertakes an annual, multi-generational migration across North America. The abundance of this species at both eastern and western overwintering sites in Central Mexico and California indicates a population decline. Success of continental-scale conservation programs for a migratory species depends on providing, maintaining, and protecting habitats at appropriate temporal and spatial scales. Here, dynamics of monarch continental-scale migration and gene flow were obtained by combined stable isotope, morphological, and genetic analyses. These analyses were applied to temporal monarch samples collected from May to September during 2016–2021 at locations in Iowa, USA and spatial collections from Pennsylvania, Delaware, Iowa, Ohio, Nevada, Idaho, Hawaii, 3 Australian locations during July and August 2016, andTexas in April 2021. Evidence of seasonal multi-generational migration was obtained through δ²H analyses of spatial collections, which was corroborated by decreased wing hue (a morphological marker for non-migratory individuals). In Iowa, 10–15% of monarchs represented migrants from southern areas throughout the breeding season and 6% were migrants from the North in midsummer. Limited sequence variation detected across the mitochondrial genome impacted the capability to detect significant population genetic variation in our North American samples. However, 2 novel substitutions were identified and predicted to be fixed among Australia samples, contributing to intercontinental differentiation from counterparts in North America. Our assessment of temporal and spatial population dynamics across the North American monarch breeding range provides insight into continental-scale migration and previously undetected mitochondrial DNA variation among globally distributed populations.

Here, we describe patterns of reproduction and flight phenology of putative Phloeosinus punctatus in giant sequoia groves and compare morphology and genotypes of beetles from sympatric giant sequoia (Sequoiadendron giganteum) and California incense-cedar (Calocedrus decurrens). Surveys conducted in 2022 revealed that numerous branches fall from giant sequoia crowns (on average ∼30 branches/tree), with 20%–50% of trees per site shedding branches, depositing breeding material for beetles on the forest floor that subsequently becomes colonized. When noninfested branches cut from mature giant sequoias were placed at the ground surface, they were colonized by P. punctatus and produced an average of 28 beetles/kg branch. Climbing and examination of sequoia crowns in 2023 showed that 75% of mature trees across 11 groves showed evidence of adult beetle entrance holes in their crowns. In 2021, tests with sticky traps showed that beetles alighted on fallen branches from 20th May to 20th August (peak landing: 2nd July); a logistic model developed from emergence data in 2021 and 2022 predicts the emergence of F1 offspring from branches between 10th July and 1st September (peak emergence: 8th August). Beetles emerging from giant sequoia preferred to settle on giant sequoia, did not reproduce in incense-cedar, and diverged morphologically from beetles emerging from incense-cedar. However, phylogenetic analysis of three genes (28S, CAD, and COI) revealed no clear pattern of sequence divergence, suggesting a single species (P. punctatus) that colonizes both hosts, though cryptic speciation may not be detectable with standard barcoding genes. Ecological and potential management implications are discussed.