Insect Species Research Articles

Knockdown of the cap ‘n’ collar isoform C gene increases the susceptibility of Agrotis ipsilon to chlorantraniliprole and phoxim

In insects, the transcription factor cap ‘n’ collar isoform C (CncC) plays a critical role in the regulation of multiple genes involved in insecticide detoxification. Knockdown of CncC genes leads to increased susceptibility to different types of insecticides in several insect species. However, the CncC gene has not yet been fully characterized in the black cutworm Agrotis ipsilon, a notorious insect pest that causes severe damage to field crops. In this study, the CncC gene (designated AiCncC) was identified from A. ipsilon. Exposure to a median lethal concentration (LC50) of chlorantraniliprole (CAP) or phoxim (PHO) strongly increased the expression of AiCncC. Silencing of AiCncC by RNA interference significantly increased the susceptibility of A. ipsilon larvae to both insecticides. Moreover, CncC/Maf binding sites were predicted in the putative promoters of two glutathione S-transferase (GST) genes (AiGSTe1 and AiGSTu1) involved in the detoxification of CAP and PHO. The transcription levels of AiGSTe1 and AiGSTu1 were dramatically decreased by silencing AiCncC. These findings indicate that AiCncC is associated with CAP and PHO susceptibility through the regulation of GST genes.

Odorant receptor co-receptors affect expression of tuning receptors in Drosophila

Insects detect odorants using two large families of heteromeric receptors, the Odorant Receptors (ORs) and Ionotropic Receptors (IRs). Most OR and IR genes encode odorant-binding “tuning” subunits, whereas four (Orco, Ir8a, Ir25a, and Ir76b) encode co-receptor subunits required for receptor function. Olfactory neurons are thought to degenerate in the absence of Orco in ants and bees, and limited data suggest this may happen to some olfactory neurons in Drosophila fruit flies as well. Here, we thoroughly examined the role of co-receptors on olfactory neuron survival in Drosophila. Leveraging knowledge that olfactory neuron classes are defined by the expression of different tuning receptors, we used tuning receptor expression in antennal transcriptomes as a proxy for the survival of distinct olfactory neuron classes. Consistent with olfactory neuron degeneration, expression of many OR-family tuning receptors is decreased in Orco mutants relative to controls, and transcript loss is progressive with age. The effects of Orco are highly receptor-dependent, with expression of some receptor transcripts nearly eliminated and others unaffected. Surprisingly, further studies revealed that olfactory neuron classes with reduced tuning receptor expression generally survive in Orco mutant flies. Furthermore, there is little apoptosis or neuronal loss in the antenna of these flies. We went on to investigate the effects of IR family co-receptor mutants using similar approaches and found that expression of IR tuning receptors is decreased in the absence of Ir8a and Ir25a, but not Ir76b. As in Orco mutants, Ir8a-dependent olfactory neurons mostly endure despite near-absent expression of associated tuning receptors. Finally, we used differential expression analysis to identify other antennal genes whose expression is changed in IR and OR co-receptor mutants. Taken together, our data indicate that odorant co-receptors are necessary for maintaining expression of many tuning receptors at the mRNA level. Further, most Drosophila olfactory neurons persist in OR and IR co-receptor mutants, suggesting that the impact of co-receptors on neuronal survival may vary across insect species.

Comparative study of endocrine pancreatic tissue in bats: Assessing variations among frugivorous, insectivorous, and nectarivorous diets

Whether the endocrine pancreas exhibits structural features to couple with dietary patterns is not fully explored. Considering the lack of data comparing endocrine pancreas and islet cell distribution among different bat species in the same study, we considered this an opportunity to explore the topic, including five species within three different predominant diets. For this, we applied morphometric techniques to compare the islets of frugivorous Artibeus lituratus and Carollia perspicillata, insectivorous Molossus molossus and Myotis nigricans, and nectarivorous Glossophaga soricina bats. Data for islet size, cellularity, and mass were equivalent between frugivorous A. lituratus and nectarivorous G. soricina, which differed from insectivorous bats. The frugivorous C. perspicillata bat exhibited morphometric islet values between A. lituratus and the insectivorous species. A. lituratus and G. soricina but not C. perspicillata bats had higher islet mass than insectivorous species due to larger size, instead of a higher number of islets per area. Insectivorous bats, on the other hand, had a higher proportion of α-cells per islet. These differences in the endocrine pancreas across species with different eating habits indicate the occurrence of species-specific adjustments along the years of evolution, with the demand for α-cells higher in bats with higher protein intake.

Carrion insects living within the bones of large mammals: insect conservation and forensic entomology implications.

Succession patterns of carrion insects on large mammal's carrion has been widely studied, notably to estimate the post-mortem interval in forensic investigations as accurately as possible. However, little attention has been paid to the carrion insects living inside these bones once a carcass is skeletonized. One very recent study documented flies emerging from pig carcasses, and only scarce authors reported the presence of other carrion insects taking advantage of the bone marrow. We, thus, aimed to (1) estimate the frequency of inner-bone space colonization by carrion insects, with particular attention to bone-skipper flies; (2) identify the insects living inside the carrion bones; and (3) determine whether or not carrion insects found within the bones can successfully exit the bones and complete their development. We extensively sampled 185 large mammals' bones collected from twelve vulture feeding stations and four isolated carcasses in southwest France and northern Spain. Sampled bones were opened, and the insects found inside were identified. For two bones, foramen, i.e., the holes providing a natural entrance and exit to the bone's inner cavity, was monitored with a camera to assess the insect's putative exit. We describe the entomofauna, i.e., the set of insect species, living within the bones, and illustrate insects' ability to exit the bones for their subsequent development and maturity. These results are discussed in the framework of carrion insect conservation and forensic entomology perspectives.

Climate change effects on animal presence in the Massaciuccoli Lake basin

Big-data mining approaches based on Artificial Intelligence models can help forecast biodiversity changes before they happen. These approaches can predict macroscopic species distribution patterns and trends that can inform preventive measures to avoid the loss of ecosystem functions and services. They can, therefore, help study and mitigate climate change implications on biodiversity conservation in fragile ecosystems. Wetlands are particularly fragile ecosystems where climate change poses severe risks and has dramatically reduced their size over the past century, with profound consequences on biodiversity and ecosystem services. Through big-data mining approaches, we can predict future wetland biodiversity trends in the context of climate change. This paper proposes such predictive analysis for a specific wetland: The Massaciuccoli Lake basin in Tuscany, Italy. This basin is a critical tourist attraction due to its rich biodiversity, making it an area of interest for citizens, tourists, and scientists. However, the region's suitability for native and non-native species is at risk due to climate and land-use change. Using machine-learning models, we predict the potential effects of climate change on animal spatial distribution in the basin under different greenhouse gas emission scenarios. The results suggest that habitat suitability has generally improved from 1950 to today, presumably owing to the targeted conservation strategies adopted in the area, but climate change will severely reduce bird biodiversity by 2050 while favouring several insect species' proliferation and other species' habitat change, even under a medium-emission scenario. This will lead to significant changes in the basin's biodiversity. Our methodology is adaptable to other wetland basins, being fully based on open data and models. The spatially explicit modelling used in this research provides valuable information for policymakers and spatial planners, complementing traditional biodiversity trend analyses.

Heterogeneric Diversity and Richness of Avifauna in a Degraded Landscape of Arial Beel in Bangladesh

Bird diversity and richness reflect the habitat quality of ecosystems. The species composition, diversity, and richness of birds were studied at Shologhar Union, a degraded landscape of Arial Beel, from March 2016 to February 2017, using line transect and point count methods. A total of 75 species of birds belonging to 14 orders and 35 families were recorded; most of them were residents (83%). Non-passerine birds were predominant (40 species, 53% of total species), with 18 families and 38 genera. Only one near-threatened species (Yellow Wattled Lapwing Vanellus malabaricus) was recorded. Among resident birds, Baya weaver (Ploceus philippinus) was dominant, and the Yellow Wagtail (Motacilla flava) was predominant among migratory birds. Most species were terrestrial (51 spp., 68% of total birds), contributing only 23% of the population. The individual rarefaction revealed the highest species richness in March and the lowest in May and June. The highest population was recorded in winter (38%), and insectivore species (40%) were the highest. No significant seasonal variation occurred in the richness of birds (Kruskal-Wallis test: K = 0.05 df = 2, p = 0.971) and in different feeding guilds (Kruskal-Wallis test: K = 0.86, df = 5, p = 0.65). Ardeidae and Sturnidae represented the highest diversified families (6 species in each, RDi = 8), and Baya Weaver contributed the highest (26%) population. The presence of different species of birds suggests that this site could provide a suitable habitat for wild birds, and restoration management of this part of Arial Beel should require conserving the habitat of avifauna. Jagannath University Journal of Life and Earth Sciences, 9(1): 19-44, 2023 (June)

Regional differences of functional and taxonomic bird diversity in tropical agroforests of Peru

AbstractDiversity and functionality of bird communities in tropical agroforests are shaped by their surrounding landscape, particularly the extent and type of natural forest. However, most evidence comes from tropical rainforest landscapes, whereas the bearing of such trends in other forest types remains understudied. We compared functional and beta diversity of bird communities in 23 cacao agroforests embedded in landscapes of two contrasting Peruvian regions: seasonally‐dry tropical forests and subtropical rainforests from the Andean foothills. Strong climatic seasonality affects both landscapes, but forest vegetation structure and complexity differ. We found higher bird species richness (n = 179 spp) and higher species turnover in the subtropical forest than in the dry forest landscape (n = 64 spp). Only in the dry forest landscape, distance from forest increased dissimilarity driven by species loss, that is, the nestedness component of beta diversity. This points to the importance of conserving dry tropical forests within the broader landscape matrix, with known benefits for pest control and cacao yield. Functional diversity indices were not influenced by forest distance in either landscape, but the proportion of insects in birds' diet decreased by 27% along a 1 km distance gradient from forest in the subtropical forest landscape. In the dry forest landscape, however, it decreased by only 3% across the same distance gradient. Far from forest (≥1 km), forest specialization decreased by ~33% and 20% in the subtropical and dry forest landscapes, respectively. These differences indicate that regionally‐adapted agroforest management is paramount for conserving bird diversity and ecosystem services as pest control. Procuring high‐canopy shade trees and adequate microhabitats for insectivorous species is essential to maintain biocontrol services in the subtropical forest. Conversely, in the dry forest enhancing low‐canopy vegetation with a focus on frugivores and ensuring forest closeness to agroforests may maximize bird diversity and their ecosystem services. A complete version of this article is translated to Spanish in the supplements.

ECR Spotlight – Adèle Léger

ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Adèle Léger is an author on ‘ Investigating the thermal sensitivity of key enzymes involved in the energetic metabolism of three insect species’, published in JEB. Adèle is a graduate student in the lab of Nicolas Pichaud at Université de Moncton, Canada, investigating how insect metabolism is affected by environmental changes such as temperature.

Development of a multiplex real-time quantitative reverse-transcription polymerase chain reaction for the detection of four bee viruses

Viruses in the families Dicistroviridae and Iflaviridae are among the main threats to western honey bees (Apis mellifera) and native bee species. Polymerase chain reaction (PCR) is the gold standard for pathogen detection in bees. However, high throughput screening for bee virus infections in singleplex PCR reactions is cumbersome and limited by the high quantities of sample RNA required. Thus, the development of a sensitive and specific multiplex PCR detection method for screening for multiple viruses simultaneously is necessary. Here, we report the development of a one-step multiplex reverse-transcription quantitative polymerase chain reaction (RT-qPCR) assay to detect four viruses commonly encountered in pollinator species. The optimized multiplex RT-qPCR protocol described in this study allows simultaneous detection of two dicistroviruses (Israeli acute paralysis virus and Black queen cell virus) and two iflaviruses (Sacbrood virus and Deformed wing virus) with high efficiency and specificity comparable to singleplex detection assays. This assay provides a broad range of detection and quantification, and the results of virus quantification in this study are similar to those performed in other studies using singleplex detection assays. This method will be particularly useful for data generation from small-bodied insect species that yield low amounts of RNA.

Honeydew: A keystone in insect–plant interactions, current insights and future perspectives

AbstractHoneydew, a sugary excretion produced by sap‐feeding insects, plays a pivotal role in shaping intricate interactions between insects and plants. This review explains the multifaceted aspects of honeydew, beginning with an overview of its production mechanisms and factors influencing its variability across insect species and plant hosts. Exploring its composition, we examine the chemical components and nutritional aspects, highlighting variations based on insect species and plant sources. The impact of honeydew on microbial communities is explored, shedding light on its role in influencing the diversity and abundance of microorganisms. Furthermore, the review investigates how honeydew affects pest behaviour and population dynamics, elucidating plant responses to honeydew deposition. In the realm of biocontrol, we examine the intricate relationships between honeydew and natural enemies, considering potential implications for integrated pest management. Beyond these individual components, the paper discusses the broader ecological consequences of honeydew in ecosystems, emphasizing the interconnected relationships between insects, plants and microorganisms. The review concludes by identifying research gaps and suggesting future directions, recognizing the need for further investigation into areas with potential applications for agriculture and ecology. This review provides a comprehensive synthesis of the current understanding of honeydew's significance in insect–plant interactions, offering insights for both researchers and practitioners in the field.

Using eDNA to play whack-a-mole with invasive species in green yard waste.

As large cities begin to overrun their landfill capacities, they begin to look for alternative locations to handle the waste stream. Seeing an opportunity to bring in revenue, rural communities offer to handle municipal waste in their landfills. However, many rural communities are also places of agricultural production, which are vulnerable to attacks by invasive insect species, which could be present in green yard waste, the component of municipal waste most likely to contain agriculturally harmful insect species. We used environmental DNA (eDNA) to determine whether green yard waste could be a pathway for invasive insect species to enter and establish in the landfill-receiving agricultural community. We identified several target species that could be in green yard waste coming from Vancouver, BC, Canada, to Central Washington State, USA. We sampled green yard waste from 3 sites every 2 weeks from June to October in 2019 and 2020. DNA was extracted from the nearly 400 samples and subjected to amplification with COI barcoding primers followed by sequencing to identify target insects in the samples. Sequence analyses identified 3 species from the target list: 2 species that are pests of deciduous tree fruits and a generalist root-feeding crop pest. This eDNA technique was useful in identifying potential invasive species in green yard waste and may prove to be an important tool informing policy on the movement of biological material across borders and stemming the spread of invasive species.

Notes on the distribution, food plants and morphology of Chlorophanus C. R. Sahlberg, 1823 species (Coleoptera: Curculionidae) in Turkey

Chlorophanus vittatus Schoenherr, 1832, known from the Caucasus and northern Iran, is here newly reported from eastern Turkey. Salix L., Populus L., Tamarix L. and Glycyrrhiza glabra L. are revealed as host plants of adults in Turkey. Feeding and mating behavior of adults were observed on leaves of G. glabra during the summer period in the Aras River valley. The lectotype of Ch. vittatus is designated, description and digital photographs of the genitalia are presented based on newly collected material. Distributional data for Ch. vittatus, Ch. excisus (Fabricius, 1801) and Ch. pollinosus (Fabricius, 1792) in Turkey are reported, the latter species is also recorded from Turkey for the first time. Chlorophanus flavescens (Fabricius, 1787) is deleted from the list of the Iranian fauna, and Ch. excisus, from the list of the Russian fauna. Characteristic ecological and distributional features of the genus Chlorophanus C. R. Sahlberg, 1823 are discussed, and notes on the riparian habitats in Turkey are given to attract attention to the necessity of their preservation. As a fragile member of the riparian insect species complex, a weevil, Corimalia aliena (Faust, 1890), formerly known only from Central Palaearctic, is reported for the first time from Turkey where it was found on Myricaria sp. in Erzurum Province. Chlorophanus excisus co-occurs with Ch. vittatus in eastern Turkey and western Iran, or at least their ranges overlap there. These two species contribute to the maximum local Chlorophanus diversity in Erzincan and Erzurum provinces. Chlorophanus micans is recorded in Crimean Mountains and Southern Bug River valley indicating a potential current contact between Ch. micans and Ch. pollinosus in Podolian Upland.

Crop type rather than production method determines functional trait composition of insect communities on arable land in boreal agricultural landscapes

Abstract To understand the potential consequences of arable land use changes for insect conservation and ecosystem functioning, it is fundamental to know how insect species with different functional traits respond to crop choice and production method. This study examined the effects of crop type and production method on functional traits of butterfly, bumblebee and carabid beetle communities using species abundance data from 78 fields in Southern Finland. Surrounding landscape composition was also accounted for. The studied traits were associated with dispersal capacity, habitat or diet specialization and phenology—the key determinants modifying species responses to agricultural disturbances and land use changes. Butterfly habitat breadth was narrowest and wingspan shortest in long‐term fallows. Fallows also supported the highest share of butterflies overwintering in early development stages and bumblebees with late‐emerging queens. The tongue length of bumblebees was longest in organic oat fields, probably due to flowering weeds with long corolla. For carabid beetles, the proportion of poor flyers and carnivores was highest in perennial crops and fallows. Carabid beetles overwintering as adults were relatively more abundant in organic than in conventional production, probably due to more intensive tillage in organic fields. In all insect groups, poor dispersers and/or specialists decreased with increasing arable land cover in the surrounding landscape. Increasing the area of long‐term fallows and perennial crops and enhancing within‐field plant diversity while maintaining landscape heterogeneity would promote insect species sensitive to agricultural disturbances and land use changes and their associated ecosystem services in boreal farmland.

Detection of edible insect as a component of snack bars using histochemical method

The edible insects are commonly used in food products, but the methods for detection are not yet established. This study presents a new bright-field method for detecting insects in food using histochemical staining (PAS-Calleja and Pasini). For the purpose of the study, snack bars from house cricket (Acheta domesticus) and mealworm (Tenebrio molitor) were produced in the concentration range of 0.0–25.0%, and for the purpose of verification, also samples from the market network were obtained. A 100% consensus of evaluators on the presence of both insect species was demonstrated in the snack bars from the concentration of 2.5%. Sensitivity and specificity were 100%, reliability was 95.4% for PAS-Calleja staining For Pasini staining sensitivity was 93%, specificity was also 100% as PAS-Calleja staining and reliability was 94.2%. The cuticle appears to be crucial for evaluating the presence of insects due to its high affinity for the PAS-Calleja staining used. A homogeneity test was carried out within the evaluation. The distance between individual fragments of insects was statistically significant at low concentrations. In conclusion, it can be assessed that evaluators can confirm the positivity of a bar samples for the presence of insects (ACH and TM) from a 1% content using the PAS-C staining histochemical method.

Symbiont infection and psyllid haplotype influence phenotypic plasticity during host switching events

Abstract Many herbivorous insect species exhibit phenotypic plasticity when using multiple hosts, which facilitates survival in heterogeneous host environments. Physiological host acclimation is an important part of it, yet the effects of host acclimation on insect feeding behaviour are not well studied, particularly for insect vectors of plant pathogens. We studied the combined effects of host acclimation and infection with a plant pathogenic symbiont on feeding behaviour of Bactericera cockerelli, an oligophagous psyllid widespread in both crop and natural habitats that feed primarily on Solanaceae and transmit an economically important plant pathogen, Candidatus Liberibacter solanacearum (CLso). We used a factorial design and the electrical penetration graphing technique to disentangle the effects of host acclimation, CLso infection and psyllid haplotype on the within‐plant feeding behaviour of B. cockerelli during conspecific and heterospecific host switches. This approach allows to connect phenotypic plasticity with the role of B. cockerelli as a vector by quantifying the frequency and duration of behaviours involved in CLso transmission. We found significant reductions in multiple metrics of B. cockerelli feeding efficiency, exacerbated by infection with CLso, which could lead to reduced transmission of this pathogen. Psyllid genotype was also important; the Central haplotype exhibited less dramatic changes in feeding efficiency than the Western haplotype during heterospecific host switches. Our study shows that host acclimation and heterospecific host switching directly alter feeding behaviours underlying pathogen transmission, and that the magnitude of feeding efficiency reductions depends on both host genotype and infection status.

Population genomics of the invasive Northern Giant Hornet Vespa mandarinia in North America and across its native range

The northern giant hornet Vespa mandarinia (NGH) is a voracious predator of other insect species, including honey bees. NGH’s native range spans subtropical and temperate regions across much of east and southeast Asia and, in 2019, exotic populations of the species were discovered in North America. Despite this broad range and invasive potential, investigation of the population genomic structure of NGH across its native and introduced ranges has thus far been limited to a small number of mitochondrial samples. Here, we present analyses of genomic data from NGH individuals collected across the species’ native range and from exotic individuals collected in North America. We provide the first survey of whole-genome population variation for any hornet species, covering this species’ native and invasive ranges, and in doing so confirm likely origins in Japan and South Korea for the two introductions. We additionally show that, while this introduced population exhibited strongly elevated levels of inbreeding, these signatures of inbreeding are also present in some long-standing native populations, which may indicate that inbreeding depression alone is insufficient to prevent the persistence of NGH populations. As well as highlighting the importance of ongoing monitoring and eradication efforts to limit the spread of this species outside of its natural range, our data will serve as a foundational database for future genomic studies into introduced hornet populations.

Development and characterization of novel EST-SSR markers for Gentiana straminea Maxim., a traditional Tibetan herb in China and cross-amplification in related species

Abstract Gentiana straminea Maxim. (Gentianaceae) is an important traditional Tibetan herb that is mainly distributed on the Qinghai-Tibetan Plateau. Despite its agricultural and pharmacological importance, there remains a paucity of microsatellite markers, particularly expressed sequence tag-simple sequence repeat (EST-SSR) markers, available for this local endemic species. In this study, based on previous Illumina transcriptome data of G. straminea, a total of 96 EST-SSR markers were initially designed and tested. Thirty-two of 96 loci (33.33%) were successfully amplified and verified for validation. Among them, 10 were polymorphic and had clear bands. The polymorphism information content values were 0.09–0.799, the number of alleles per locus ranged from 3 to 14, and the levels of observed and expected heterozygosity were 0.078–0.722 and 0.238–0.884, respectively, which suggested a high level of information. Moreover, cross-amplification was successful for 10 loci in two other related species, Gentiana macrophylla Pallas and Gentiana dahurica Fischer. These EST-SSR markers provide a valuable tool for investigating the genetic diversity related to quantitative traits and population genetic studies on G. straminea and related species in sect. Cruciata Gaudin.

Microbial and insect oils: A sustainable approach to functional lipid

AbstractThe increasing global population, coupled with the effects of climate change on agricultural activities has spurred a demand for sustainable food production to meet human needs. In response to this, there has been a growing interest in sustainable food production initiatives. One of such initiatives is harnessing microbial and insect lipids as valuable ingredients to address increase in demand for lipids across various sectors, including functional food, nutritional supplements, and biodiesel production. Over the last decades, there has been increasing scientific investigations exploring lipid from algae, microbes, and insects as alternatives to traditional agro‐ and marine‐based sources. This review, therefore, presents progress made in microbial and insect oils production, with emphasis on sustainability. Emerging extraction techniques, regulatory and safety requirements, and challenges that exist in the production and utilization of these new lipids are also discussed. The review shows that lipids from a wide range of oleaginous microorganisms and insect species have the potential to serve as a valuable ingredient for healthful food preparation. However, challenges such as cultural acceptance, lack of standardized regulations, high cost, and low yield associated with most emerging environmentally friendly extraction technologies continue to hinder widespread use or adoption of microbial and insect lipids on a global scale. These challenges call for innovations to reduce cost of production and improve lipids yield. So far, a substantial progress has been made in the utilization of readily available feedstocks such as industrial food wastes and sugar‐rich industrial wastewater to grow insects and microorganisms which will significantly reduce the processing costs.

All-you-can-eat buffet: A spider-specialized bat species (Myotis emarginatus) turns into a pest fly eater around cattle.

Determining the dietary spectrum of European insectivorous bats over time is the cornerstone of their conservation, as it will aid our understanding of foraging behavior plasticity in response to plummeting insect populations. Despite the global decline in insects, a restricted number of arthropod pest species thrive. Yet past research has overlooked the potential of European bats to suppress pests harmful to woodlands or livestock, in spite of their economic relevance. Here we investigated the diet composition, its breeding season variations and pest consumption of an insectivorous bat species (Myotis emarginatus), at the northern edge of its range (Wallonia, Belgium). We also explored the prey ecology to gain insight into the hunting strategies and foraging habitats of this bat species. We used DNA metabarcoding to amplify two COI markers within 195 bat droppings collected in June, July and August, thereby identifying 512 prey taxa predominated by Diptera, Araneae and Lepidoptera. Overall, in 97% of the samples we detected at least one of the 58 potential pest taxa, 41 of which targeting trees. The June samples were marked by a diet rich in orb-weaver spiders, in accordance with the archetypal diet of M. emarginatus bats. However, during the highly energy demanding July-August parturition and lactation period, roughly 55% of the dropping samples contained two cattle fly pests (Stomoxys calcitrans and Musca domestica). Moreover, among the 88 Diptera species preyed upon by M. emarginatus in July and August, these flies accounted for around 50% of the taxa occurrences. This plasticity-the switch from a spider-rich to a fly-rich diet-seems providential considering the dramatic ongoing drop in insect populations but this involves ensuring bat-friendly cattle farming. Our results revealed that bats widely consume pest entomofauna, thereby highlighting their potential role as allies of forest managers and farmers.

Hirundo rustica (Barn Swallows) and Tachycineta bicolor (Tree Swallows) select wetlands in agriculturally intensive landscapes, as revealed by GPS tracking

Abstract Aerial insectivorous birds breeding in North America have experienced decades of population declines for reasons hypothesized to be related to changes in their insect prey. In agricultural landscapes, land management practices affect insect communities, leading to concerns that ongoing trends toward more intensive cultivation could affect the ability of farmland-breeding aerial insectivores to forage and provision their offspring with aerial insect prey. To understand how differences in agricultural intensity may affect the foraging behavior of different aerial insectivore species, we used GPS tags to compare the foraging movements and foraging habitat use of 2 species with different foraging ecologies, Hirundo rustica (Barn Swallow) and Tachycineta bicolor (Tree Swallow), breeding at 17 sites in agricultural landscapes in Saskatchewan, Canada. Although we identified differences in foraging behavior consistent with each species’ reported ecological traits, including T. bicolor foraging farther and over larger areas than H. rustica, overall foraging behavior was similar between species. Resource selection function analyses indicated that both species used wetlands disproportionately often relative to local wetland availability, especially when detected farther from their nests. Hirundo rustica and T. bicolor both also avoided cropped foraging habitat, using it proportionally less than it was locally available. In landscapes with greater wetland cover, both species selected for wetland habitat more strongly, and among T. bicolor, higher wetland density decreased maximum foraging distance and home range area. In contrast, we found no effect of crop cover on foraging habitat selection or foraging movements. These findings suggest that H. rustica and T. bicolor breeding in Saskatchewan agroecosystems share similar foraging strategies, with wetland habitats appearing to be highly important despite comprising only a small proportion of land area. Overall, these results indicate that protecting wetland habitats should be a priority for aerial insectivore conservation in the intensive agricultural landscapes of the Canadian prairies.