Biotropica

Fruit resource availability can influence the local abundance of avian frugivores through bottom-up regulation, but whether greater resource availability translates into higher visitation rates to fruiting trees remains poorly understood. Greater fruit availability could increase visitation by supporting larger frugivore populations, or reduce visitation to individual trees if increases in frugivore abundance are not proportionate to those in fruit availability or if frugivores distribute their foraging effort. Understanding these relationships can provide insights into the relative role of abundance and trait-based mechanisms in structuring plant-frugivore communities. We compared fruit availability, avian frugivore abundance, and frugivore visitation rates on fruiting trees across two protected wet tropical forest sites: Anamalai Tiger Reserve in the Western Ghats and Namdapha Tiger Reserve in the Eastern Himalaya. Specifically, we quantified the availability of bird-consumed fruits across one-ha patches, estimated local abundances of major frugivore groups, and tested whether visitation rates on individual fruiting trees were related to frugivore abundance, body mass, and degree of frugivory. We found that small-seeded fruit availability was significantly higher in Anamalai than in Namdapha. Local abundances of several relatively small-bodied frugivore groups, including bulbuls, barbets, fairy-bluebirds, and mynas, were also higher in Anamalai. However, visitation rates of several frugivore groups on individual fruiting trees were higher in Namdapha. Visitation rates across all avian frugivore species were associated with frugivore abundances only in Anamalai, and not associated with body mass or degree of frugivory in either site. Thus, although greater fruit availability was likely associated with higher frugivore abundance, this increase in abundance did not consistently translate into higher visitation rates at individual fruiting trees, which provides some support for the resource dilution hypothesis. Our results highlight the importance of considering fruit resource availability and frugivore abundance when examining variation in tropical plant-frugivore interactions.

Lianas are an integral component of tropical forests, and their increasing abundance may alter forest structure and function. Whether infested host trees are shorter and smaller-crowned because lianas suppress them, or because lianas preferentially colonise already small trees, has remained unresolved. We used a longitudinal dataset of individual liana infestation histories spanning fourteen years (2011-2025), combined with terrestrial laser scanning (TLS)-derived structural metrics for 251 trees across 67 species on Barro Colorado Island, Panama. Bayesian analyses showed that persistently infested trees were shorter (11.0%), with smaller crown projected area (22.3%) and crown volume (25.9%) than never-infested trees; the 95% credible intervals for these effects excluded zero. Pre-infestation crown architecture did not credibly predict subsequent colonisation. These patterns are more consistent with persistent infestation imposing lasting architectural legacies than with strong pre-existing architectural susceptibility, suggesting rising liana abundance may progressively reduce forest stature and canopy density, with implications for tropical carbon storage projections.

The Peruvian Andes, and especially its slopes towards the Amazonian Basin are well-known biodiversity hotspots for plants and animals, which represent the visible part of biodiversity. However, not much is known about microeukaryotic diversity, despite the significant role protists play in the ecosystem. Based on a molecular survey of the diversity of Arcellinida (a group of amoebae well known for its environmental sensitivity and restricted geographical distributions), we estimated its diversity along an elevation gradient spanning more than 3000 meters. Surprisingly, Neotropical forest Arcellinida were less abundant and diverse than in most other extratropical biomes; nevertheless, communities differed strongly in their taxonomic composition as compared with forests in higher latitudes. Notably, sequences related to Trigonopyxis were most abundant, whereas this group occurs only marginally in extratropical settings. Elevation influenced beta diversity, showing different assembly processes occurring at different elevation belts. Canopy cover positively influenced both phylogenetic and taxonomic diversity, showing the importance of above and below ground integration in tropical forests.

Frugivory is essential for the maintenance of tropical forests, influencing seed movement, spatial structure, and ecosystem functioning. Although frugivory interactions are well documented at local scales, we still know relatively little about how network structure varies across biogeographic regions, particularly in equatorial lowland forests. In this study, we compare frugivory networks in lowland forests in the Guiana Shield (South America), Malaysia (Southeast Asia), and Central Africa (Gabon and Cameroon). Because these sites occur at similar latitudes, they provide a useful setting to examine how evolutionary history and biogeographic context, rather than climate alone, might shape the structure of the network. We analyze patterns across regions, focusing on implications for frugivory interactions and, ultimately, seed dispersal. Guided by the Integrative Hypothesis of Specialization (IHS), we focus on the role of megafauna and other large-bodied frugivores, which are important consumers of large fruits and dispersers of large seeds, and have experienced different historical trajectories in each continent. We also considered whether smaller frugivores, such as rodents, might partially compensate for the loss of Megafauna in the Americas through seed handling and caching behavior. The pantropical comparison revealed structural and functional differences between the studied frugivory networks. In the Guianas, lacking megafauna, the frugivory network showed strong modularity with nestedness within modules, forming a marked compound topology. Alternatively, in Central Africa, with elephants and great apes, the network showed intermediate modularity and nestedness, reflecting a balance between local compartmentalization and regional integration. Finally, in Malaysia, the network was predominantly nested, with a few highly connected species, especially figs and flying foxes, that linked most of the partners. Across continents, frugivory networks tend toward a compound topology, but the relative influence of modular and nested components shifts with biogeography, evolution, and ecology.

Arboreal camera trapping is an emerging remote sensing tool for building plant-frugivore interaction networks with enormous potential to provide new insights into seed dispersal as an eco-evolutionary process. Interaction data derived from camera trap videos broadly falls into two categories: visitation, indicating the presence of an animal in a tree, and intake, indicating true fruit consumption. These linked approximations of seed dispersal may or may not provide distinct sets of information, shaping our understanding of network dynamics, yet the extent to which emergent network structure depends on variable choice is unknown. To address this gap, we deployed camera traps in the canopy of 21 plant species in the Costa Rican tropical dry forest, an endangered biome with sparse community-wide plant-frugivore interaction data. Our objectives were: 1) Quantify plant-frugivore network structure in the tropical dry forest via network, group, and species-level metrics; and 2) Compare metrics between visitation and intake networks. We find strong structural patterns of low connectance, low nestedness, high modularity, and low niche overlap that differ significantly from null expectations in the same direction in both networks. The visitation network exhibited significantly greater modularity & species degree than the intake network, while the intake network exhibited significantly greater plant niche overlap than the visitation network. These findings suggest that the likelihood of consuming fruit on camera differs across species, which may have downstream consequences on other emerging metric estimations. Researchers seeking to build quantitative plant-frugivore networks should therefore consider visitation and intake variables in concert when relying on camera trap data. This work provides foundational plant-frugivore interaction data for a critically endangered biome and enhances our understanding of camera trapping as a remote sensing tool in frugivory and seed dispersal research.

Elevational gradients provide a framework for understanding how environmental filtering reorganises communities and interactions, but plant-pollinator interactions along temperate forest elevational gradients remain overlooked. We studied early-spring understorey communities at four forest sites spanning the foothills towards the timberline (450-1,000 m a.s.l.) in the Krkono[s]e Mountains, Czechia. Across six transects per elevation, we quantified flowering plant species richness, floral resources and traits, and video-recorded flowers, yielding 4,003 pollinator visits. We analysed elevational patterns in species richness, community composition, floral traits, and quantitative network characteristics. Visitation frequency and flowering plant and pollinator species richness peaked at intermediate elevations. The contribution of dipteran relative to hymenopteran pollinators increased towards higher elevations, principally because of non-hoverfly flies, whereas individual bee groups showed no uniform response. Floral resources and traits showed no uniform elevational responses, although total nectar sugar availability peaked at the highest site because of the dominant Vaccinium myrtillus. Most notably, both network-level specialisation and mean species-level specialisation were generally greater at the two higher elevations, whereas nestedness was lower and other network characteristics showed no consistent patterns. These findings suggest that shifts in pollinator composition and dominant floral resources potentially shaped interactions along the gradient. The increasing specialisation with elevation contrasts with the generalisation often expected under reduced partner availability and indicates that forest networks may follow elevational patterns not predicted from open habitats. Despite limited site-level replication, this study provides, to our knowledge, the first community-wide characterisation of plant-pollinator interactions along a temperate forest elevational gradient and identifies patterns requiring evaluation across replicated gradients.

Forest canopy height is sensitive to shifts in demography (which affect tree size distributions and abundances of short-vs. tall-statured species) and allometry. Demographic and allometric effects on canopy height have not previously been studied across a large region. We analyzed more than two million individual tree measurements from about 60,000 remeasured inventory plots in non-plantation forests across 19 ecoregions of the conterminous United States to quantify changes in aboveground live tree biomass (AGB), canopy height, and its demographic and allometric components from ~2003-2025. We tested the hydraulic limitation hypothesis, which predicts decreasing tree height with increasing hydraulic stress. AGB was strongly correlated with canopy height across ecoregions, and AGB change was strongly correlated with canopy height change over time. Canopy height change was positive in nearly all eastern ecoregions but varied in sign across western ecoregions. Demographic shifts led to increased canopy height in most eastern ecoregions but decreased canopy height in most western ecoregions. In contrast, allometric shifts, averaged across species, caused either positive or no significant change in ecoregion-mean canopy height. Our results were consistent with several predictions of the hydraulic limitation hypothesis: (i) intraspecific allometric shifts were more positive for understory than for canopy trees, (ii) across ecoregions, canopy height was positively correlated with precipitation and negatively correlated with vapor pressure deficit, and (iii) canopy height change over time was positively correlated with precipitation change. However, our results suggest modifications to the hydraulic limitation hypothesis, because allometric shifts tended to be positive, even in ecoregions with decreasing precipitation and increasing vapor pressure deficits. Such allometric shifts, which seem counter to the hydraulic limitation hypothesis, may be caused by CO2-driven increases in water-use efficiency. Whatever their cause, allometric shifts should be accounted for to avoid biased estimates of canopy height change and biomass change.

Understanding the spatial distribution of species and their patterns of endemism is necessary for establishing effective conservation priorities. Despite the vital pollination services bees provide, Californias native bee distribution patterns remain largely unexplored relative to plants and butterflies. We analyzed bee species richness and endemism across California and their concordance with plant distributions. Richness was high across areas of the California Floristic Province, including the Sierra Nevada, San Francisco Bay Area and Central Coast, South Coast Ranges, and the Transverse and Peninsular ranges. Bee endemism was more localized, concentrated in the San Joaquin Valley, eastern Sierra Nevada and adjacent Great Basin, Sierra Nevada foothills, and California deserts. Because richness and endemism appear to operate at different spatial scales and likely respond to different environmental drivers, effective conservation strategies must address both. Additionally, conservation plans that incorporate both plant and bee diversity are needed to achieve more comprehensive biodiversity protection.

Urban and rural woodlands have become important habitats for wildlife, providing opportunities for ecological and ethological adaptation to changing environmental conditions. Due to limited tree resources in anthropogenic woodlands, different species are often forced to interact more closely, and one possible outcome of such interactions is hybridisation. Recent studies have shown that hybrids between the uncommon Syrian Woodpecker (Dendrocopos major) and the often common Great Spotted Woodpecker (Dendrocopos syriacus) are relatively widespread, yet rare, in sympatric populations (Bakai et al. 2026). To understand the factors determining their occurrence in rural and urban landscapes, we conducted an intensive survey across Europe. We examined the effects of environmental factors, particularly woodland characteristics, as well as the co-occurrence of hybrids with the parental species and European Starlings (Sturnus vulgaris) (hereafter Starling). Spatial analyses revealed that the parental species generally have allotopic distributions, with Syrian Woodpeckers (hereafter SW) being more common in scattered woodlands in both rural and urban landscapes, while Great Spotted Woodpeckers (hereafter GW) are more commonly associated with denser woodlands and forests. Although in some areas the two species can co-occur, which provides opportunities for interspecific hybridisation, hybrid offspring showed no clear preference for any particular woodland type. However, they tended to occur in proximity to one of the parental species, usually the species that was locally rarer. Starlings were not identified as a factor influencing hybrid distribution. These results suggest that hybrids have a relatively broad ecological tolerance, potentially facilitated by heterosis. These findings contribute to our understanding of the factors influencing interspecific hybridisation and may have implications for the management of urban and rural woodlands to preserve habitats for the SW, an uncommon and strictly protected species in the west of the European Union.

1. Assessing the conservation value of secondary forests and reforestation is important for conservation planning. Butterflies are widely used as indicators, and fruit-feeding butterflies are often used in biodiversity assessments in tropical landscapes. 2. We examined fruit-feeding butterfly diversity, abundance, and community composition across a primary forest, a secondary forest, and a plantation forest in northern Vietnam. We sampled butterflies nearly monthly during one year using baited traps. 3. Primary and secondary forest supported higher species richness than plantation forest. Moreover, while secondary forest had mainly a subset of species found in primary forest, the plantation forest had a distinct butterfly fauna. 4. Butterfly abundance and community composition varied across months, without showing a clear seasonal pattern. 5. Our results suggest that secondary and plantation forests do not fully replace primary forests, but they contribute meaningfully to butterfly conservation in human-modified tropical landscapes.

To implement adequate nutritional landscapes to bumble bees and inform conservation efforts, we need a better understanding of how different pollen sources impact bumble reproductive performances and phenology. We assessed the impact of multiple native pollen on bees reproductive success by feeding 40 wild-caught Bombus impatiens and B. griseocollis queens with either commercially wildflower pollen mix commonly used to breed Bombus queens (control group) or 75% red maple pollen (Acer rubrum) and 25% pollen mix (RM group). In a second experiment, we monitored the reproductive success of 45 microcolonies of workers, harvested from B. impatiens colonies. Microcolonies were fed either: 1) pollen mix (N=15), 2) pollen mix and hawthorn (Crataegus canadensis, N=15), or 3) pollen mix and sumac (Rhus typhina, N=15). In experiment 1, RM significantly increased reproductive outputs for both species. RM-fed founding queens were twice more likely to produce workers, and produced them significantly earlier, though total number of workers did not vary between groups. However, RM-fed founding queens produced significantly more brood cells, males and gynes than control colonies, and produced them significantly earlier. In experiment 2, we found an interaction between initial colony diet and current microcolony diet. Overall, workers harvested from RM-fed colonies produced significantly more brood cells and males than workers harvested from control colonies. However, when fed hawthorn pollen during experiment 2, workers from control colonies performed as well as workers from RM-fed colonies. This suggests carry-over effects from early pollen sources provided to colonies on workers, which may be circumstantially offset by pollen sources with specific nutrient profile. Using detailed nutritional information of each pollen (including data on 32 nutrients), we provide nutritional requirements of pollen to support bumble bee reproduction, especially regarding vitamin B3 and vitamin C contents. This study will help inform land managers and captive breeding programs on the ideal pollen sources for bumble bees to ensure reproductively successful colonies.

Aims In forest ecosystems, tree species composition and diversity are fundamental drivers of biodiversity and many species are closely associated to specific tree species as hosts. Saproxylic diversity across tree species may be shaped by interactions between ecological and environmental factors, such as resource availability. However, a throughout and unbiased quantification of diversity across tree species is missing. We investigated patterns an drivers of saproxylic beetle diversity across European tree genera while accounting for differences in sampling effort. Location Europe Methods We used a large dataset, of 25 studies, comprising 500,000 deadwood-dependent beetles, representing 1041 saproxylic beetle species, sampled from 29 tree genera. We accounted for sampling effort by estimating diversity using coverage-based standardization across Hill numbers. We than used linear models to identify drivers of saproxylic beetle diversity across tree genera and assessed differences in community composition using Nonmetric Multidimensional Scaling (NMDS). Additionally, the most abundant beetle families were identified for a subset of 14 genera. Results Quercus supported the highest richness of infrequent, frequent, and highly frequent species, while Fagus exhibited the highest observed (unstandardized) species richness. Beetle communities were less differentiated when focusing on infrequent species, whereas tree genera were separated when focusing on frequent and highly frequent species. In addition, we found that resource availability and maximum tree height best predicted infrequent beetle diversity, whereas resource availability was the main driver of frequent species. In contrast, the same analyses for unstandardized data indicated postglacial occurrence as an important factor for infrequent species. Main conclusions Although resource availability supported the species area hypothesis, standardized data revealed higher richness on smaller trees, partly contradicting this pattern. Our results highlight the importance of accounting for sampling bias and promoting tree diversity, particularly oaks, to sustain saproxylic beetle diversity.

Rapid urbanization is altering the seasonal life cycles, or phenology, of urban trees. Diverse species composition and heterogeneous urban thermal environments can generate pronounced phenological variation within cities, yet such fine-scale seasonality remains poorly understood. This limits the ability to anticipate localized ecosystem services and disservices, including canopy cooling and pollen exposure. Here, we analyzed individual-tree phenology and their response to temperature across 76 cities in the contiguous United States by integrating municipal street-tree inventories, PlanetScope satellite time series, and 1-km near-surface urban air-temperature data. We quantified intra-city and cross-city phenological variation, estimated species-level associations between phenology and fine-scale urban temperature, and tested whether these associations vary with regional climatic context. Intra-city phenological variation rivaled cross-city variation for 33.3% of species in spring and 53.7% in fall. Temperature-phenology associations were widespread: warmer local urban environments were associated with earlier spring onset in 51.5% of cases and delayed fall senescence in 66.5%, with approximately two-thirds of these responses cascading to longer growing seasons. These associations varied with regional climate, generally showing stronger spring advancement and fall delay in cooler and wetter cities, but weaker or reversed responses in hotter or drier cities. Together, these results suggest that urban tree phenology is shaped by interactions among fine-scale urban temperature, species identity, and regional climate. Accounting for this heterogeneity can improve predictions of urban forest function and inform climate-resilient species selection and management. Plain Language SummaryStreet trees within the same city do not all leaf out in spring or lose their leaves in fall at the same time. This seasonal timing, called phenology, affects services such as shade and cooling, as well as disservices such as pollen exposure. We studied individual tree phenology and their temperature response in 76 U.S. cities using street-tree records, satellite observations, and local air-temperature data. We asked how much phenology varies within cities, how it responds to neighborhood-scale temperature differences, and whether these responses depend on regional climate. Variation within a city was often as large as variation among cities, especially in fall. Trees in warmer parts of cities generally leafed out earlier and lost their leaves later, often extending the growing season. However, these responses were stronger in cooler and wetter cities and weaker or sometimes reversed in hotter or drier cities. These findings show that urban tree seasonality depends on local temperature, species identity, and regional climate, which should be considered when selecting and managing trees for future cities. Key PointsO_LISubstantial within-city phenological variation is not captured by city-level averages. C_LIO_LIFine-scale temperature shaped phenology and growing-season length, but responses varied across species, cities, and phases. C_LIO_LITemperature sensitivity depended on regional climate, weakening or reversing in hotter or drier cities. C_LI

Understanding when species diversification and phenotypic evolution are coupled remains a central challenge in macroevolution. Such coupling may depend on the traits considered, phenotypic integration, or the geographic context in which diversification occurs. Here, we investigate these relationships in Ithomiini, a diverse Neotropical butterfly tribe whose diversification is strongly associated with the Andes-Amazonia system. We quantified forewing and hindwing size and shape for 1,618 individuals representing 291 species using geometric morphometrics, and combined these data with phylogenetic comparative methods, diversification-rate estimates, and spatial analyses of species distributions. Evolutionary rate shifts were largely trait- and wing-specific, indicating limited coupling between forewing and hindwing evolution. Across the phylogeny, wing size evolution and extant wing size were not associated with species diversification, nor was hindwing shape evolution. By contrast, forewing shape evolutionary rates showed a positive association with diversification. Spatial analyses revealed that this coupling was geographically concentrated in the Andes, where high diversification rates coincided with elevated forewing size and shape diversity and increased forewing evolutionary rates. Hindwing diversity, by contrast, more closely tracked phylogenetic diversity and showed weaker or opposing relationships with diversification. Our results show that diversification and phenotypic evolution in Ithomiini are neither generally coupled nor fully independent, but linked in trait-specific and geographically structured ways. More broadly, they highlight the need to decompose complex phenotypes and integrate spatial context when testing macroevolutionary coupling.

Hibernation is a critical phase in the annual cycle of boreal bats, especially near the northern limit of their range where winter conditions are severe and suitable hibernacula are limited. In Finland, anthropogenic structures, such as abandoned bunkers, commonly serve as hibernacula for bats. In this research, we investigate how the size characteristics of bunkers affect species composition and abundance of hibernating bats. The length of the bunker was the best predictor of the presence and abundance of bats. The longest sites ([~]25-26 m) had the highest probability to host all studied species, or group of species of bats, specifically Eptesicus nilssonii, Plecotus auritus, and Myotis bats. Eptesicus nilssonii appeared to be a generalist species, utilizing a variety of bunkers regardless of their length or temperature regime. Still, its number per bunker was relatively low. The highest numbers of Myotis bats were observed in the longest bunkers with stable temperature. The number of P. auritus was positively related to the bunker length; however, it was rare in the studied hibernacula. Different species showed different patterns in hibernacula space usage. Eptesicus nilssonii hibernated in any part of the bunker, while Myotis bats used the most remote from the entrances areas in small sites, and occupied the whole area of the longest bunkers.

Madagascar hosts exceptional biodiversity and endemism, yet its native bee fauna remains poorly characterised. We assembled and cleaned the first comprehensive occurrence dataset for Malagasy bees, reducing 10,721 raw records to 4,071 validated occurrences covering 218 georeferenced species of the 224 checklist species across six families (89.3% endemic). Despite near-complete checklist coverage, the dataset remains critically sparse for Madagascar's size, with most species documented by only a few records. Sampling was highly uneven across taxa: most genera were underrepresented while a few were disproportionately sampled due to ecological prevalence, detectability, and collector specialisation. Spatial concentration within limited grid cells amplified these biases. Temporally, effort varied markedly, with historical peaks driven by individual collectors and a post-2010 shift toward Apidae-dominated records. Spatially, 79.9% of 25x25 km grid cells intersecting Madagascar held no bee records, and 77.1% of records fell within 2.5 km of roads, mirroring global sampling patterns. Sampling clustered near major cities, with common species consistently found near roads and rare species spread across wider distance ranges. Among 231 Key Biodiversity Areas (KBAs), 68.4% were entirely unsampled; sampled KBAs held only 26.7% of all records, and sampling remained uneven even there, leaving substantial undetected diversity across most sites. These results reveal pervasive temporal, spatial, taxonomic, and collector-driven biases, underscoring the need for targeted surveys within KBAs and beyond roadsides to improve coverage of data-deficient species and strengthen conservation assessments.

Wildflower plantings are an important conservation measure for supporting wild bee diversity. They aim to enhance floral resources for nutrition, but do not explicitly consider that bees also require suitable nesting and overwintering resources. Wildflower plantings may provide nesting habitat for ground-nesting bees, but the effects of soil management, e.g. ploughing, on ground-nesting bees are hardly known. To study how ploughing and age of wildflower plantings affect ground-nesting bees, we sampled bees on ploughed and unploughed wildflower plantings aged 0-4 years. We used emergence traps to sample bees directly after emergence from the ground, allowing inference on nest numbers. We found that ploughing and wildflower planting age negatively affected overwintering bee nest numbers. Nesting peaked in the year of wildflower planting establishment and declined thereafter, indicating lower habitat suitability at later successional stages. Annual ploughing caused the greatest reduction in nest numbers (-72 %), providing evidence for an ecological trap.

Assessing breeding phenology using singing intensity can potentially provide insights into a species' responses to climate or habitat change. Although male passerines are known to sing elaborate songs during the breeding season, females of several tropical passerines also sing. The Nilgiri Flycatcher (Eumyias albicaudatus) is an endemic dimorphic songbird found in the southern Western Ghats of India. Despite its limited distribution and its ecological significance as an indicator species of cloud forests, very little is known about its vocal behaviour and breeding ecology. To examine sex-specific differences in vocalisation patterns, we analysed 294 male and 102 female focal songs from two pairs of birds. We then used data from a year-long automated recorder placed near a breeding pair to study the species' singing phenology using the BirdNET Analyser. The two sexes broadly produced similar songs, although males' songs included more notes at a faster pace. The sex-specific detectors failed due to this high similarity among songs of the two sexes, but we were able to automate species-level detection (F1-score = 0.795 at a confidence threshold of 0.1). We found strong seasonality in vocal activity, with peaks in singing during the breeding season, and identified a diurnal peak at dawn. More data are required to parameterise differences in annual vocal activity between the sexes. These detection patterns provide a framework for a landscape-wide examination of Nilgiri Flycatcher phenology and occurrence. This study suggests that automatic detectors can be a reliable tool for assessing singing phenology in birds and provide insights into breeding periods.

Wildlife monitoring in arid environments is complicated by substantial temporal and spatial variation in animal activity driven by unpredictable environmental conditions. For highly mobile species, movements across the landscape may further influence activity recorded at fixed monitoring locations, raising questions about whether short-term surveys adequately represent patterns of site use. We examined temporal variation in acoustic activity of the threatened Pilbara Leaf-nosed Bat (Rhinonicteris aurantia Pilbara form), a highly mobile, cave-roosting insectivorous bat inhabiting the arid Pilbara region of north-western Australia. Acoustic activity was monitored continuously at two permanent diurnal roosts for up to two years, comprising 1601 detector-nights across three detector locations. We tested relationships between nightly activity and environmental conditions, detector location and anthropogenic disturbance. Activity varied substantially through time and among detector locations. Moon illumination and cumulative rainfall were strongly associated with activity, but their interaction differed between roosts: activity was highest under low moon illumination and low cumulative rainfall at Chateau Cave, whereas activity at Daltons was highest under low moon illumination and higher cumulative rainfall. Activity also differed markedly between detector positions within Chateau Cave, and humidity, temperature and artificial light at night had additional location-specific effects. Other measures of anthropogenic disturbance, including cave entry, blasting and mining activity, had comparatively weak support. The contrasting environmental relationships among locations demonstrate that acoustic activity at permanent roosts is strongly context dependent. For a species capable of extensive movements among roosts, temporal variation in activity may reflect behavioural responses and redistribution of individuals across the landscape rather than rapid demographic change. We suggest that facultative nomadism may provide a useful hypothesis for understanding temporal variation in roost use by Pilbara Leaf-nosed Bat. More broadly, our results demonstrate that short-duration acoustic surveys of highly mobile species in arid environments may provide an incomplete representation of longer-term site use and should incorporate temporal replication and environmental context when used for conservation and impact assessment.

Colony defence is critical for the survival of wild honeybees but presents a challenge for local populations and beekeepers. Apis mellifera scutellata is an important pollinator in its native range, a large area of Southern and Eastern Africa 1, but is reputed for its explosive temperament. Here, we present data demonstrating that this behaviour is only exhibited by a small fraction of colonies, while others are relatively docile. This sheds new light on this subspecies and on its likely evolutionary trajectory. We further characterize the different elements of this defensive response and compare them to that of A. m. carnica and A. m. mellifera. We show that each subspecies invests differently in the two steps of the behavioural sequence (alert and attack). Furthermore, our results suggest that the task of attacking is carried out by specialized workers in carnica, but not in the other subspecies tested, highlighting subtle differences in colony organization across subspecies. Finally, we discovered that defenders from A. m. scutellata and scutellata-hybrid colonies can locate a target that was stung up to 2 h and 3 h earlier, respectively, whereas European bees could only do so for 30 min. This long-term marking could confer an advantage against returning predators with few weak points, such as honey badgers and humans wearing protective clothing. Overall, we offer a fresh perspective on this controversial but important subspecies of honeybees, with implications for both future studies and daily management.