Insect Conservation and Diversity

Urbanization often reduces local biodiversity, yet cities can maintain surprisingly high total species richness at broader spatial scales. This paradox has led to the "cities-as-bioarks" hypothesis, which proposes that protected remnant habitats within cities can function as refuges for native species. However, most evidence supporting this hypothesis comes from higher latitudes, and it remains unclear whether remnant habitats in low-latitude cities can serve the same role. We surveyed ant communities across 60 sites in Atlanta, Georgia (USA), spanning streetscapes, manicured parks, and forested parks, to test whether relatively undisturbed urban forests support the highest native diversity. Contrary to the bioark prediction, native species richness was lowest in forested parks and highest in habitats with intermediate disturbance. Community composition varied with habitat structure, but surface temperature was not a significant predictor of richness or composition. Instead, native abundance and richness declined strongly with increasing abundance of the invasive Asian needle ant, Brachyponera chinensis, a forest-adapted invader capable of dominating relatively intact habitats. In contrast, two other invasive species, the red imported fire ant Solenopsis invicta and the Argentine ant Linepithema humile, were largely restricted to more disturbed habitats and had comparatively weaker associations with native diversity loss. These findings refine the bioark hypothesis by demonstrating that habitat protection alone may be insufficient to conserve insect diversity in warmer regions, and instead must be paired with active invasive species management.

Urban green spaces are increasingly recognised as important refuges for biodiversity, yet their ecological value depends strongly on design and management. Here, we investigate how fine-scale structural and microhabitat components shape urban ant assemblages, using ants as indicators of broader arthropod responses to urbanisation. Ant communities were sampled in twelve urban green spaces in Cordoba (southern Spain) over a ten-year period (2004 to 2013) using pitfall traps, alongside detailed characterisation of vegetation structure and ground-layer microhabitats. In total, 38 species and 25,578 individuals were recorded. Microhabitat variables explained 58% of the variation in species occurrence. Community differences among microhabitats were driven primarily by nestedness, with dense herbaceous cover acting as a core habitat and edge-related components contributing disproportionately to beta diversity. Tree abundance showed a unimodal relationship with species richness, with maximum diversity at intermediate densities, while shrub and lawn cover had weak or inconsistent effects. Fine-scale elements such as leaf litter, stones, woody debris, and small bare-ground patches strongly influenced species occurrence by providing thermal refugia, nesting substrates, and foraging opportunities. The invasive Argentine ant (Linepithema humile) exhibited strong but spatially restricted dominance and species-specific negative effects on native ants, emphasising the role of habitat context in mediating invasion impacts. Our results demonstrate that urban biodiversity is maximised by enhancing fine-scale habitat heterogeneity rather than increasing green cover alone. We highlight practical design principles for urban green infrastructure that prioritise structural diversity and ground-layer complexity to support resilient arthropod communities.

A basic question in ecological research and biodiversity monitoring concerns the estimation of species abundances from trap catches. As a case in point, a Malaise trap can yield thousands of arthropod individuals, but how this count should be converted to numbers of individuals per unit area has remained an open question. Here, we supplement observational data with an experimental approach targeted at quantifying catchability. We released marked insects in a boreal forest and examined their capture rate by a grid of Malaise traps around the release location. We estimated insect movement rates, mortality rates, and Malaise trapping capture rates by fitting a joint species movement model to these data. As a methodological novelty, we show how to convert the movement model parameters to the expected number of captured individuals, given their actual population density. Our results show that multiplying the sample content by 30 000 yields a rough estimate of the number of individuals per hectare. This conversion factor depends on the species, generally decreasing with increasing body size. We apply the estimated conversion factors to conclude that typical boreal forest contains some four million insect individuals per hectare, out of which around half belong to Diptera. SIGNIFICANCE STATEMENTTraditionally, the Malaise trap method has been used for assessing the state of the local communities and to estimate population abundances. However, a topical question is: how does the number of individuals observed in a sample relate to the true density of individuals in the surrounding community? To answer this question, we implement a movement model parametrized by a carefully designed mark-recapture experiment, in which we are able to obtain taxon-specific conversion factors for different groups of insects. We found that different insect groups come with different conversion factors, causing a mismatch between sample contents and true community composition. Thus, treating the sample contents as a direct representation of the reference community will be misleading.

Wild bees face declines, and forests may serve as critical habitats for pollinators. However, how forest composition and the associated floral environment shape pollen provisioning and resource partitioning among cavity-nesting bees remains poorly understood. Here, we leveraged BEF-China, a large-scale subtropical forest biodiversity experiment with experimentally controlled plant (tree and shrub) communities, to investigate how forest composition and spatial context shape pollen provisioning, resource partitioning, and reproductive success of cavity-nesting bees. We used DNA metabarcoding to analyze floral composition of pollen provisioned by five cavity-nesting bee species, with samples collected from BEF-China across three years (2022- 2024). By comparing pollen taxonomic composition from whole-nest pooled samples and individual brood-cell samples with the experimentally planted species pool, we characterized dietary patterns and temporal dynamics of five bee species. Bees primarily relied on floral resources from the surrounding landscape, with planted trees providing essential but temporally restricted pollen supplements during specific phenological stages. Co-occurring bee species exhibited staggered nesting phenology and distinct dietary preferences for different plant families, with fine-scale resource differentiation even during periods of phenological overlap. Our results suggest that managed forests support cavity-nesting bees by providing critical woody floral resources during specific phenological gaps and offering stable nesting environments. To mitigate pollinator declines, forest management should prioritize maintaining diverse, phenologically complementary flowering vegetation within and surrounding forest stands. This ensures temporal continuity of pollen availability throughout the nesting season, which is particularly crucial for restoring pollinator services in simplified forest landscapes.

O_LIAgricultural intensification can support the expansion of introduced species which are highly adapted to human-modified landscapes, but the mechanisms by which this occurs are often unclear. C_LIO_LIHere we investigate the spatial ecology of a rapidly expanding introduced bumble bee (Bombus impatiens) and a native congener (B. mixtus) in agricultural landscapes of southwestern British Columbia, Canada. We used microsatellite genotyping and spatially explicit capture-recapture models to compare the foraging distance of the two species, and fitted hierarchical models to compare their abundance, behaviour (nest searching vs foraging), and lineage survival as a function of landscape composition and configuration. C_LIO_LIWe found that B. impatiens had a broader foraging range than B. mixtus, and that its colony/worker abundance were positively associated with the surrounding area of residential gardens, but decreased relative to B. mixtus abundance in response to increasing seminatural area. In contrast, B. mixtus colony abundance decreased in landscapes with a greater area of intensively managed berry crops. C_LIO_LIWe observed fewer B. impatiens queens per survey in landscapes with more low-disturbance landcover, and hypothesize space use of this species could be shaped by concentration on potential nesting habitat. Consistent with this observation, nest searching behaviour was more common for B. impatiens queens, while B. mixtus queens were primarily observed foraging, suggesting these two species derive different value from agricultural landscapes during colony establishment. C_LIO_LIFinally, we found that the rate of lineage re-capture between 2022 colonies and 2023 spring queens was nearly 10-fold higher for B. impatiens than for B. mixtus, indicating a greater capacity of the introduced species to complete its life cycle in agro-natural landscape mosaics. C_LIO_LIOur results suggest that differences in spatial ecology may contribute to the differential success of these two species in human-modified landscapes, and provide insight into the mechanisms by which land-use change shapes community composition. C_LI O_FIG O_LINKSMALLFIG WIDTH=184 HEIGHT=200 SRC="FIGDIR/small/723627v1_ufig1.gif" ALT="Figure 1"> View larger version (62K): org.highwire.dtl.DTLVardef@1e72eacorg.highwire.dtl.DTLVardef@a958a0org.highwire.dtl.DTLVardef@1f970b6org.highwire.dtl.DTLVardef@156f522_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical abstract. Coloured diagrams of B. mixtus and B. impatiens are credited to Elaine Evans and the Xerces Society, with permission.

Urbanization presents a significant challenge to pollinator communities worldwide, altering ecological dynamics and species interactions. Understanding the impact of urbanization on pollinators is crucial for developing strategies to mitigate pollinator declines and enhance urban biodiversity. This study investigates hymenopteran pollination ecology in the inter-Andean valley of Quito, Ecuador, using participatory science data. Our dataset, consisting of 2113 hymenopteran records and 556 pollination interactions, reveals complex insect-plant relationships in Quitos urban environment. We found that alien plant species interacted with more pollinator taxa on average, in contrast to the more specialized interactions involving native plant species. Non-native honeybees (Apis mellifera) play a dominant role in these pollination networks, strongly shaping overall network structure. Additionally, both native and alien plants acted as pollination hubs, driving important and diverse interactions. The study documents numerous previously unreported pollination interactions, underscoring the value of participatory science in revealing novel ecological insights. Our findings suggest that Quitos green spaces function as important refuges for urban pollinators. The use of participatory science records proved invaluable for advancing knowledge of urban pollination ecology, despite its inherent limitations. Encouraging native plant cultivation and public awareness can help mitigate pollinator declines in urban settings. This study adds to growing evidence on urban pollinator ecology and highlights participatory science as a practical tool for addressing ecological challenges in cities.

Urban pollinator gardens can provide refugia and support diverse populations of native bees amid threats from habitat destruction, pesticides, and potential ecological pressures from the introduced honey bee (Apis mellifera (Linnaeus, 1748)). The University of California, Berkeley, maintained a native bee garden at the Oxford Tract research facility to study the biodiversity, phenology, and foraging habits of urban bees from 2003 to 2009. That garden was decommissioned, and a new garden was re-established in 2019. Using diversity observations from the early 2000s garden and non-lethal sampling techniques, we characterized plant-pollinator interactions between flowers and urban bees in the newer bee garden with a bipartite interaction network. Across 12 flower species, we observed two non-native pollinators, the honey bee (A. mellifera) and the alfalfa leafcutter (Megachile rotundata (Fabricius, 1793)), along with at least ten native bee species across three families (Apidae, Halictidae, Megachilidae). We found that, despite the garden being created for native bees, honey bees accounted for 84% of all pollination interactions. The most abundant native bees were sweat bees (Family: Halictidae). Generalist interactions dominated the network, as both honey and sweat bees foraged on most available flowers. Honey bees showed a significant positive correlation with floral abundance, visiting flowers with the highest number of inflorescences, whereas native bees did not show this preference. These results indicate that native bee garden stewardship could benefit from greater floral diversity, while avoiding the dominance of any single species with high floral abundance, thereby reducing the likelihood of direct competition with honey bees.

Remote island systems with small landmasses and reliable estimates of human occupancy are ideal model systems to disentangle the roles of global climatic changes and local human occupation on biota. Here, we used mitochondrial and nuclear genomic data from five endemic Fijian Lasioglossum (Homalictus) bee species to infer changes in effective population size (Ne). These ground-nesting bees are native, with non-specialised floral visitation habits, and distributed across the elevational gradient. All lowland species and populations showed strong signals of increasing Ne that correspond to the timing of human occupation of Fiji, but not Holocene climatic change. Highland populations, with greater isolation and present in regions less affected by anthropogenic impacts, did not show evidence of recent rapid increases in Ne. Population expansion rates across the elevational gradient differed between taxa, with significantly earlier and larger increases in predominantly lowland species than those with more restricted ranges in the highlands. This is consistent with the movement of people inland from coastal regions and into montane elevations of the island, and corresponding landscape changes that benefit the ecology of these bees. Specific life history traits of these bees, combined with substantive clearing of forest cover and floristic changes at lower elevations, has likely increased nesting opportunities and abundance of invasive floral resources. Our findings contrast with recent evidence that human occupation of Fiji has resulted in decreased ant biodiversity and raise the paradoxical possibility that human-mediated environmental changes may benefit some native montane tropical insect faunas.

O_LIIslands are priority areas for the study and conservation of biodiversity, as they frequently harbour distinct lineages. Yet they are particularly threatened by the global change. In the frame of an accelerated biodiversity crisis, many insular species risk disappearing before they are even discovered. C_LIO_LIFireflies, despite their ecological and cultural significance, remain poorly investigated, especially in temperate regions, where they have shown marked decline over the last decades. C_LIO_LIWe investigated firefly diversity across a Mediterranean biodiversity hotspot by genotyping 114 fireflies of the genus Luciola from 29 locations across the Tuscan Archipelago and the adjacent Italian peninsula and applied phylogenetic and species delimitation methods to characterise genetic differentiation and its geographic structure. C_LIO_LIWe found an unexpectedly high level of genetic differentiation in this area. Phylogenetic inference recovered six deeply divergent and geographically structured mitochondrial lineages: three restricted to Elba Island and three to the Italian Peninsula. Genetic divergence among these lineages ranged from 1.97% to 4.58%, values comparable to or exceeding those typically observed among distinct species. Accordingly, species delimitation methods consistently supported their status as distinct species. C_LIO_LIThe coexistence of three divergent lineages on Elba Island suggests a biogeographic scenario characterised by ancient island colonisations and possible in situ diversification. These findings reveal a previously unrecognised depth of evolutionary diversity in Italian fireflies and identify the Tuscan Archipelago as a priority area for future research on firefly evolution and conservation, emphasizing that fireflies are a major gap in our knowledge of insect biodiversity in Europe. C_LI

Pollinator populations are facing worldwide declines, underscoring conservation needs. Yet, conservation assessments still mostly rely on occurrence data, often derived from heterogeneous and opportunistic observations. While such data can inform on species presence and distribution, they may overlook important markers of population declines. This is particularly problematic for social species such as bumble bees, which typically exhibit low effective population sizes despite high abundance of workers observed in the field. Despite these putative pitfalls, the relationship between occurrence-based and genetic-based estimates remains largely unexplored in social bees. We here investigated spatio-temporal genetic patterns in five Swiss Bombus species representing contrasting population trajectories over the last century: B. humilis and B. sylvarum (stable), B. ruderatus (increasing), B. pomorum (regionally extinct), and B. veteranus (declining). Museum specimens collected between 1929 and 2023 were genotyped at 11 microsatellite loci to compare spatio-temporal fluctuations in genetic diversity and population structure with occurrence data. Overall, multilocus heterozygosity and allelic richness remained stable in all species during the time period investigated, indicating that the diverging population trends did not result in substantial variation of genetic diversity. In contrast, strong and significant shifts in allelic frequencies between time periods were detected in three species, suggesting recent immigration events. Isolation by distance was detected in the cold-adapted B. veteranus, while the extant warm-adapted species (B. humilis, B. sylvarum, B. ruderatus) showed high levels of gene flow between locations. In B. pomorum, increasing genetic homogenization was observed before extinction. Altogether, these findings show that genetic diversity indexes are not the most adapted tools to monitor conservation status of social bee populations, and that estimates of population structure such as allelic shifts may be more informative. Moreover, these results highlight the importance of monitoring metapopulation dynamics and ensuring connectivity among populations to facilitate gene flow and enable demographic rescue processes.

Tropical forest succession can reorganize biodiversity not only by changing species richness, but also by filtering the functional traits that represent ecological strategies. Harvestmen are highly sensitive to microclimatic and structural changes in Neotropical forests, yet their functional diversity remains poorly explored. We investigated taxonomic and functional diversity of harvestmen in a local scale, an Atlantic Forest remnant in southeastern Brazil containing forest patches at different successional stages. Standardized nocturnal active searches and leaf-litter sampling yielded 384 individuals belonging to 14 morphospecies. Functional diversity was quantified from four morphological traits using Hill numbers (q = 0, 1 and 2), morphofunctional ordination, beta-diversity partitioning and environmental models based on forest-structure variables and PCA-derived gradients. Functional diversity was highest when rare species were weighted equally and declined strongly from q = 0 to q = 2, indicating that uncommon species carried much of the regional morphofunctional variation. Functional alpha diversity was positively associated with taxonomic alpha diversity, and Mantel tests showed that taxonomic and functional dissimilarities among sampling points were significantly correlated. However, formal beta-diversity partitioning refined this interpretation: functional beta diversity was dominated by nestedness-resultant dissimilarity rather than turnover, suggesting that functionally poorer assemblages represented contracted subsets of the regional trait space. Morphofunctional analyses identified compact, robust and long-legged species groups, and environmental models showed that lower vegetation structure, litter depth and forest-maturity gradients significantly influenced functional diversity. These findings indicate that mature, structurally complex Atlantic Forest patches help maintain the full spectrum of harvestman morphofunctional strategies and highlight harvestmen as promising models for trait-based conservation ecology. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/731358v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@1f91597org.highwire.dtl.DTLVardef@1f89aa6org.highwire.dtl.DTLVardef@7141b8org.highwire.dtl.DTLVardef@191accc_HPS_FORMAT_FIGEXP M_FIG C_FIG

Plants, as structural elements of habitats, contribute greatly to the maintenance of local biodiversity through their biological interactions. In this study we explore whether their rarity, according to Rabinowitzs (1981) three criteria, is related to the richness and diversity of arthropods and other plants they are associated to, in a gypsum-rich steppe. We first analysed whether the geographic abundance and ecological specialisation of 32 characteristic and dominant plant species are related to the diversity (richness and phylogenetic diversity (MPD)) and degree of local specialisation of arthropods associated with them (1,694 taxa). Then, we focused on a non endemic and non specialized plant in the study area (Krascheninnikovia ceratoides) to explore the effect of population size on two types of interactions: aerial arthropods and plant facilitation. Results indicate that: 1) plant species abundance (geographical range) is not related to the richness or MPD of communities of associated arthropods, 2) plant species ecological specialization (edaphic endemisms or gypsophiles) do not contribute differentially to the maintenance of singular arthropod communities, and 3) the community of aerial arthropods and plants interacting with K. ceratoides in a small population are not necessarily less diverse than those in patches of similar size in a large population. Results also revealed that the two plant species with fewer interactions (one rare, one widespread) do show the highest singularity in their interactions with arthropods. Our study illustrates the important contribution of rare plants to the conservation of local biodiversity.

1. Ruby-throated hummingbirds (Archilochus colubris) exhibit flower preferences and readily visit human subsidies like feeders. However, foraging behavior and plant-animal interactions may vary across spatial, temporal, and landscape gradients. Despite the popularity and ubiquity of Ruby-throated Hummingbirds in the eastern U.S., there has never been a quantitative assessment of their flower preferences or feeder use across broad scales. 2. We investigated how feeder visitation, flower visitation, and flower trait preferences vary by latitude, season, and land use in the northeastern United States using over 6 million occurrence records of Ruby-throated Hummingbirds and flowering plants, >2,100 annotated hummingbird-flower interactions, and >2,700 feeder visit occurrences. 3. We found that hummingbird feeder use declined over the year, increased with latitude, and was higher in developed landscapes. Flower visitation increased over the year across all latitudes, with higher visitation in developed landscapes. Finally, we found that native plant use diverged between landscapes, such that the probability of visiting a native flower increased over time in non-developed land uses but declined over time in developed ones, demonstrating that hummingbirds track the advancement of native floral phenology and use non-native, cultivated flowers as a human subsidy due to either availability or preferences. 4. Our preference and network models revealed that while hummingbird-plant network structure was similar across landscapes, the composition of important taxa shifted from native, wild species like Monarda and Impatiens to non-native, cultivated species like Salvia. 5. Using trait-based models of flower visitation, we found that hummingbirds preferred native, tubular, and red/orange flowers fitting the hummingbird pollination syndrome despite visiting >260 different plant species. Red and orange flowers were preferred across all seasons, suggesting color may be a reliable signal of nectar availability across species and contexts. Native and tubular flowers were strongly preferred during the breeding season; however, preferences relaxed during spring and fall migration. 6. These findings reveal the consistent preferences of Ruby-throated Hummingbirds for native, tubular, and red/orange flowers, and underscore how spatial and temporal factors reshape foraging behavior and trait preferences. Our results also highlight the value of community-collected data in characterizing plant-pollinator interactions across broad spatial and temporal scales.

AimOur aim was to study the effects of energy availability and landscape habitat heterogeneity on bird taxonomic and functional gamma-diversity and propose conservation guidelines based on the results. LocationSouthern and Central Finland Time Period2009-2020 Major Taxa StudiedBirds MethodsWe derived biodiversity variables from bird monitoring line transects to assess the effects of latitude, longitude, and landscape composition, configuration, and heterogeneity at multiple spatial scales: 100, 500, 2,000, and 5,000 m. We tested the effects of these landscape metrics on the total community, bird ecological guilds (species richness and abundance), functional diversity, and overall species specialization index. ResultsWe found clear evidence supporting a positive effect of energy (latitude and soil fertility) and habitat amount on bird abundances. Our results also revealed a northward increasing trend in functional diversity and species specialization. Habitat heterogeneity positively affected both bird abundance and species richness. Heterogeneity of land cover types was shown to promote abundances, while functional measure of landscape heterogeneity was positively connected to species richness. Land use with high anthropogenic activities, such as urban areas and cropland, negatively affected forest specialists and species sensitive to human activities. Main ConclusionsEnergy and habitat heterogeneity and amount are major mutually nonexclusive factors shaping bird communities in Finnish landscapes. Nonetheless, certain land use types favour some guilds while excluding others (for example, urbanized areas or cropland favouring open area species while excluding old-growth forest specialists), showing that biodiversity conservation is a matter of specialized landscapes. Furthermore, different measures of landscape heterogeneity demonstrated positive relationships with the studied bird guilds, highlighting the consistency of the species-heterogeneity relationship.

Frugivorous insect larvae are dependent on fruiting plants for development, leading to complex host-parasite interactions that may be influenced by many factors at various scales. We compared the relative effects of factors at the individual, neighborhood, and landscape scales in forest patches. Our results suggest that in areas like upstate New York, where agricultural land uses are dominant, individual scale factors are the most influential. Specifically, parasitism increased with host fruit crop size, but was not associated with host species richness or proximity to forest edge. Notably, the most parasitized hosts were non-native species, including Frangula alnus Mill. (Glossy Buckthorn), indicating a potential role of invasive species to shape host-parasite interactions in our system. Our results underscore the importance of host-specific traits in structuring parasitism patterns and suggest management could consider both the ecological context of host traits and the influence of invasive species at multiple scales.

The introduction of alien species into new habitats stands as a pressing economic and ecological challenge but it is also essential for unveiling evolutionary processes. The introduction of the Argentine ant (Linepithema humile) led to the spread of a single supercolony through different continents and thousands of kilometres like in Europe, from Northwest Spain to Greece. It was assumed that the high invasiveness of the species mainly relied on the lack of agonism among colonies, an effect derived from its introduction. However, recent studies suggest that local adaptations and evolutionary divergence could involve the disruption of the Argentine ant "empire" into a mosaic of competitive colonies. We investigated how isolation affects population divergence by comparing mainland and island populations in two distant regions colonized in Spain and in Greece with morphology, agonism, cuticular hydrocarbons, and genetic diversity of ant workers. Our results showed that all colonies sampled belonged to the most spread supercolony in Europe (main supercolony) except one sampled in Crete (Heraklion; Greece), which resulted to be a supercolony not registered in Europe. The Heraklian supercolony showed a different chemical and genetic profile and hostile agonism towards the other Greek colonies. Differences between islands and mainland colonies belonging to the main supercolony were higher in Galiza than in Greece. Surprisingly, the chemical profile of the Cretan colony belonging to the main supercolony showed more similarity with the Galizan colonies than with the Greek mainland, suggesting that L. humile may have been introduced into Greece through this island instead of the mainland. Our study suggests that local adaptations in Argentine ant colonies can trigger competition between colonies. Our data strongly support the existence of a candidate supercolony which highlights either ongoing introductions of L. humile in Europe or gaps in our understanding of its metapopulation dynamics.

AimHuman land-use change contributes to biodiversity declines, but also creates new niches that facilitate novel biotic interactions. These interactions can reshape ecological communities and ecosystem function, yet remain poorly understood. Swiftlets and swallows in Southeast Asia present a classic example: coexistence is facilitated by fine-scale diet partitioning, with population sizes historically limited by available nesting substrates. However, several species now nest on manmade structures, particularly "nest farms" built to harvest edible swiftlet nests. We evaluated whether land-use change, especially the spread of nest farms, is leading to breakdowns in niche partitioning and increased competition among six sympatric swiftlets and swallows. LocationNorthern Borneo MethodsWe calculated geographic niche overlap using species distribution models (SDMs) with different environmental predictors, hypothesizing greater overlap when land-use variables were included. We then implemented joint species distribution models (JSDMs) to partition shared environmental responses from potential biotic interactions, predicting that competition would emerge as negative residual correlations. We used sightings from citizen-science datasets and structured surveys to evaluate the influence of climate, land-use, nest farms, morphology, and foraging behavior on species occurrences. ResultsSDMs that included land-use variables showed high niche overlap, suggesting that human activity homogenizes niches. The optimal JSDM, based on structured survey data, identified distance to nest farms as the strongest predictor of occurrence for all species, with species showing both positive and negative responses. Morphology and behavior had small effects, and residual correlations were weak, indicating limited unexplained biotic interactions. Main conclusionsHuman activity, through the creation of artificial nesting sites, broadly drives co-occurrence of swallows and swiftlets across our study region. These effects appear to operate primarily through environmental filtering rather than direct competition. Our findings reveal substantial and complex impacts of land-use change and anthropogenic nest sites on the distribution and composition of aerial insectivore communities.

The multivoltine non-native box tree moth, Cydalima perspectalis (Lepidoptera: Crambidae), was accidentally introduced in several continents and exhibited a very rapid expansion in its invaded ranges, colonising around 40 countries in less than twenty years. Initially observed in urban areas, it quickly spread to forest stands, causing significant damage to boxwood trees. If the role of the ornamental plant trade in its fast invasion has been investigated, the insects flight capabilities has thus far been overlooked, limiting estimations of its natural dispersal. In this context, we assessed the flight performance of the adults and investigated potential effects of sex, age and generation using computer-monitored flight mills. Under these controled conditions, we estimated the distance flown per night and over the adults lifespan in both sexes for each generation. The adults were able to fly on average 18 km within their lifespan, even though distances flown were highly variable, including several females capable of performing long-distance flights (up to 150 km). The distances covered were partly correlated with the age and body mass of the adults. Mated females flew longer distances than virgin ones, but long dispersal seemed to limit their fecundity. Finally, the overwintering generation presented the highest flight capabilities with individuals able to cover 22 km on average while the late summer generation covered only 10 km. The box tree moth showed good dispersal abilities that likely played a significant role in its rapid local expansion, while human-mediated dispersal favoured its long-distance dispersal.

Xenoglossa cressoniana, also known as Tetraloniella cressoniana or Xenoglossodes cressoniana, is a eucerine bee known mainly from the US Great Plains. The species was described from a female collected somewhere in Texas in the early 1900s. Here, we report rediscovery of this species in Texas after over a century with no intervening observations. While surveying north Texas ranches, we collected six specimens, including both males and females, at four sites northwest of the Dallas-Fort Worth Metroplex. Xenoglossa cressonianas range, the Great Plains and parts of the deep South, covers a large proportion of the United States. The southern and northern Great Plains, and deep South, have been historically overlooked by most bee researchers. Our results show the urgent need to increase data from under-sampled regions, even within a heavily sampled country such as the US.

The global spread of invasive insects poses serious ecological and economic threats to forest ecosystems. Euwallacea fornicatus and E. perbrevis are cryptic ambrosia beetles native to Southeast Asia that have invaded multiple regions worldwide, damaging diverse woody hosts through gallery formation and fungal symbiont inoculation. We compiled confirmed and novel occurrence records to describe their global distributions, reconstruct invasion histories and likely origins using mitochondrial COI phylogenies, and compare their potential distributions through models based on bioclimatic variables. Euwallacea fornicatus has expanded rapidly over the past decades, establishing in North America (2003), Israel (2009), South Africa (2016), South America (2020), Australia (2021), Europe (2022) and Turkey (2024). In contrast, E. perbrevis has an earlier but slower invasion history, with establishments in Hawaii (1918), Central America (1979), Oceania (1982), and North America (2004). Phylogenetic analyses revealed at least six independent introductions for each species. Euwallacea fornicatus primarily originated from native populations in China, Taiwan and Vietnam, whereas E. perbrevis from Indonesia and Thailand, with additional introductions from unknown sources. Secondary spread from invaded regions is also likely. Distribution models indicated distinct climatic niches. Euwallacea fornicatus tolerates broader thermal ranges and drier conditions, enabling establishment from subtropical to temperate regions, whereas E. perbrevis appears restricted to tropical climates. Only 32% of predicted suitable habitat overlapped, indicating low coexistence potential. The broader climatic tolerance and faster recent spread of E. fornicatus highlights a higher invasion risk and greater management challenges. These findings provide key insights to strengthen biosecurity strategies aimed at preventing further spread. Key messageO_LIWe updated the global distribution and likely invasion routes of two cryptic ambrosia beetles. C_LIO_LIWe identified multiple independent and secondary introductions worldwide. C_LIO_LIWe revealed distinct climatic niches and limited habitat overlap. C_LIO_LIWe showed higher invasion risk for E. fornicatus due to broader climatic tolerance. C_LIO_LIWe identified high-risk regions for surveillance based on climate suitability. C_LI