American Journal of Primatology

Nonhuman primates (NHP) are crucial models of human health and disease and offer the opportunity to bridge the gap between basic research and the clinic. Given the ethical considerations, high costs, and logistical constraints associated with NHP studies, careful planning is essential to maximize scientific rigor while minimizing animal use. Statistical power calculations, to determine optimal sample size, require knowing the expected number of animals at each timepoint, a challenge for longitudinal studies that must account for natural deaths or disease during a study. Here, we leveraged data from a recent study detailing NHP life- and healthspans to develop a web-based NHP study design tool, available at midas.wakehealth.edu. For 11 NHP species relevant to biomedical research, users can provide study details to generate estimates of sample counts based on natural healthspan trajectories. We envision this tool being used by colony managers and investigators for both study design and monitoring colony health over the course of a study.

Across different modalities, signals play a core role in attracting mates and influencing mating success. In several non-human primate species, females produce calls during mating that are thought to promote male competition over receptive females. The extent to which social system characteristics modulate the function of copulation calls remains less clear. We studied copulation calls in wild Guinea baboons (Papio papio), who live in a multilevel society structured around units in which females associate and mate almost exclusively with a single male. We hypothesised that females use copulation calls as an indirect form of mate competition, with competition increasing in larger units. In addition, we hypothesised that females are more likely to mate again after calling. We analysed 6116 copulations between 2014 and 2025, involving 99 reproductively active females and 78 subadult and adult males. Females produced copulation calls in 72.7% of copulations, with large inter-individual variation. Neither unit size nor its interaction with the female's swelling size or the presence of simultaneously receptive females affected the probability of calling. A survival analysis with a subset of the data (2353 copulations) revealed no effect of calling on the latency to the next mating. Our results render the hypothesis that female Guinea baboons use calls in indirect mate competition unlikely. Yet, the probability of calling varied with sexual swelling size, suggesting that calls signal female fertility. Possibly, Guinea baboon copulation calls represent an evolutionary remnant, no longer under selective pressure, and can be considered index signals of female fertility.

Behavioral thermoregulation allows animals to reduce the physiological costs associated with variation in the thermal environment, yet little is known about how chimpanzees respond behaviorally to the cool and humid conditions of tropical montane forests. We examined how microclimatic conditions influenced resting posture, sun/shade use, substrate use, vertical position within the canopy, and day nest use in eastern chimpanzees (Pan troglodytes schweinfurthii) in Nyungwe National Park, Rwanda. From March 2024 to February 2025, we collected 5,661 individual behavioral records during 486 contact hours and paired behavioral observations with measurements of ambient temperature, water vapor pressure, wind speed, and rainfall. Bayesian mixed models showed that temperature was the most consistent climatic correlate of resting behavior. Under cooler conditions, chimpanzees were more likely to adopt heat conserving postures, particularly curled and huddled postures, and to use day nests. As temperature increased, chimpanzees increased their use of shade, shifted from arboreal to terrestrial resting, and used lower canopy strata more frequently. Higher wind speed was also associated with reduced use of the upper canopy, whereas rainfall, water vapor pressure, and fruit availability generally showed weaker or behavior-specific associations. These findings indicate that chimpanzees in a cool montane forest flexibly adjust posture, solar exposure, substrate use, vertical position, and day nest use in relation to local thermal conditions. Resting behaviour may therefore provide an important context for behavioral thermoregulation, extending our understanding of chimpanzee thermal ecology beyond the warmer lowland and savanna habitats that have received most previous attention.

Classic socio-ecological theory predicts that males and females experience different sources and mechanisms of social competition. Whether these differences translate into sex-specific structural properties of dominance hierarchies remains unclear. Here, we compiled 156 dominance interaction matrices from 80 published studies and extracted three commonly used metrics - hierarchy steepness, linearity and the directional consistency index - to investigate the structural characteristics of male and female dominance hierarchies across primates. All three metrics were strongly affected by methodological and demographic variables. Steepness increased with the number of recorded interactions and group size, linearity decreased as matrices became sparser, and directional consistency declined with increasing numbers of interactions. Steepness covaried positively with both linearity and directional consistency, indicating that groups with steeper hierarchies also exhibited more linear and more directionally consistent relationships. We found no sex differences in steepness, linearity or directional consistency. These results suggest that current metrics primarily reflect variation in the sampling effort and the rate of interaction of the recorded behaviour and appear therefore not to capture potential sex differences in the forms of competition. Our findings highlight the need for alternative measures of power asymmetries that are less confounded by sampling effort and demographic variation to better understand how competition and conflict are structured across primate societies.

Predation is a major selective force shaping lemur behaviour and population dynamics, yet direct observations remain rare, particularly for small nocturnal species. Here, we document predation on mouse lemurs (Microcebus spp., Cheirogaleidae) in Andohahela National Park, south-eastern Madagascar, and using complementary evidence from radio-telemetry and owl pellet analyses. Two radio-collared individuals were confirmed as prey of endemic snakes, Ithycyphus oursi and Madagascarophis meridionalis (both Pseudoxyrhophiidae), representing the first documented records of Microcebus predation by these species. Examination of owl pellets and prey remains from three sites and from three owl species revealed a single predation event by Asio madagascariensis (Strigidae), likely involving M. tanosi, no evidence of mouse lemur predation by Tyto alba (Tytonidae) despite high local prey availability, and a single and first predation record from Athene superciliaris (Strigidae). Material from A. superciliaris roosts was otherwise dominated by invertebrates, indicating that primate predation is likely opportunistic. Together, these findings expand the known predator guild of mouse lemurs and suggest that snake predation is rarely detected, and its contribution to mouse lemur mortality and population dynamics is likely underestimated. Our findings demonstrate how combining behavioural field observations with dietary evidence can uncover otherwise undetected predation events and clarify predator prey relationships in nocturnal primates.

Understanding how closely related species coexist in highly seasonal and unpredictable environments is central to studies of ecological differentiation and niche partitioning. We investigated the feeding ecology of sympatric populations of Microcebus murinus and M. griseorufus within a contact zone in Andohahela National Park, southeastern Madagascar, across dry and wet seasons. Using a combination of direct behavioral observations (1,611 feeding records), fecal sample analyses (n = 56), and vegetation phenology surveys, we quantified dietary composition, seasonal shifts in resource use, and habitat-related variation. Seasonal changes in diet were pronounced, with dry-season feeding dominated by exudates and wet-season diets incorporating greater proportions of fruit and flowers, closely tracking phenological patterns at both sites. Diets of both species were dominated by plant resources, but consistent interspecific differences in dietary strategy were evident. Although both species consumed comparable proportions of insect prey, M. murinus showed pronounced wet-season increases in the use of high-sugar, carbohydrate-rich floral resources (15.9%) and hemipteran-associated honeydew (30.6%). In contrast, M. griseorufus relied more consistently on predictable exudates throughout the year. Fecal analyses supported observational data but revealed differences in the detectability of dietary components, with increased representation of invertebrates in the wet season and seeds in the dry season. These results indicate substantial dietary overlap but consistent differences in resource use, suggesting that coexistence is facilitated by fine-scale trophic differentiation within a broadly shared omnivorous niche. Such subtle but persistent differences in feeding strategy likely reduce competitive overlap and enable continued sympatry in a climatically variable and resource-limited system.

Among Madagascar primates, the sportive lemurs (family Lepilemuridae) have seen their species diversity increase from eight in 2005 to 26 in 2009 mostly by applying the phylogenetic species concept to DNA barcode data. Despite the genus being speciose, only one case of sympatry is known from northern Madagascar, where two sportive lemur species described based on low mtDNA divergence, Lepilemur ankaranensis and Lepilemur milanoii, were found to co-occur at the center of their joint distribution range. Here, to clarify the taxonomy of these two species and examine their sympatry, we apply an integrative taxonomic framework to genomic and morphological data from 84 individuals of L. ankaranensis and L. milanoii, encompassing their entire distribution range and the forest of Analafiana, beyond their southernmost limit. Using clustering, multivariate, and isolation by distance analyses, we find no evidence of a sympatric zone and show that despite clear genetic differentiation between regions, the genomic and morphological diversity of the L. ankaranensis, L. milanoii-Analafiana group is clinal and explained by geographic distance. These results clarify that L. milanoii is a junior synonym of L. ankaranensis and that the Analafiana forest population belongs to L. ankaranensis, extending its distribution. It further implies that the 'sympatric' zone, the Andrafiamena forest, hosts conspecific individuals with slightly differentiated mtDNA backgrounds, rather than slightly differentiated sympatric species. Lastly, we re-evaluate the IUCN conservation metrics of L. ankaranensis, which continue to qualify as Endangered (EN) under the B1ab(i-v) criteria.

Animals face a fundamental trade-off between food-related competition and predation risk in how they allocate time and behavior. Nocturnal mammals offer a particularly tractable system for testing this trade-off because moonlight creates a natural, quantifiable gradient in both predation risk and the visibility needed for safe movement. We used minute-by-minute focal observations of nine kinkajous (Potos flavus; 4 female, 5 male) in Panama to test how fruit abundance and moonlight predicted nocturnal activity budgets (percent time traveling, feeding, resting) and nightly travel distance. Beta-family generalized linear mixed models and a linear mixed model of log travel distance showed that fruit abundance was positively associated with percent time traveling and with nightly travel distance, and negatively associated with percent time feeding: kinkajous traveled more and fed less per hour when fruit was abundant, consistent with movement between many nearby productive trees rather than prolonged feeding at a few. Males traveled less as moonlight increased, while females traveled more. Rainfall had no independent effect. We interpret the sex-reversed moonlight response as evidence that moonlight elevates predation risk for males while facilitating movement for the more food-limited females of this frugivorous carnivore.

BackgroundThe ecological dynamics between Trypanosoma parasites and their wild mammalian hosts, such as bats and armadillos, are complex. Recent 18S rRNA metabarcoding studies have reported extraordinary levels of hidden parasite diversity and frequent multi-lineage coinfections within individual wild hosts. However, the boundary between genuine biological coinfection and methodological artifact remains difficult to establish. Based on Gauses principle of competitive exclusion, the mammalian bloodstream represents a highly constrained niche where stable coexistence of identical ecological competitors is theoretically rare. We hypothesize that previously reported hyper-diverse Trypanosoma coinfections are largely bioinformatic artifacts, and that true intra-host dynamics instead favor single-lineage dominance. MethodsTo test this hypothesis, we sequenced samples from 27 wild armadillos (Dasypus novemcinctus) and 26 bats from Ecuador. The 18S rRNA gene was amplified via nested PCR and sequenced using an Oxford Nanopore Technologies MinION platform. We developed a progressively stringent bioinformatics pipeline to evaluate coinfection hypotheses. Raw reads were processed through three alignment scenarios: Lenient, Moderate, and Conservative. These scenarios modulate sequence identity, mapping quality (MAPQ), and coverage thresholds to effectively isolate true biological signals from alignment ambiguity. ResultsUnder lenient alignment parameters, the resulting profiles mirrored previous literature, exhibiting massive apparent intra-host multi-lineage diversity. However, as bioinformatic stringency increased to conservative thresholds ([≥] 98% sequence identity, [≥] 99% coverage, and MAPQ [≥] 30), artifactual pseudo-coinfections collapsed. The highly restricted dataset demonstrated overwhelming single-lineage dominance, validating only three active mixed infections out of the retained samples. Furthermore, our rigorous pipeline isolated rare but genuine biological signals, including the detection of Trypanosoma cruzi marinkellei--historically considered a bat-restricted subgenus--within the terrestrial armadillo cohort. We also confirmed the presence of T. cruzi DTU III (TcIII) in Ecuadorian armadillos, representing a significant biogeographical record for the region. ConclusionsOnce methodological noise is computationally stripped away, active multi-strain Trypanosoma coinfections in the host bloodstream are revealed to be ecologically anomalous. Our findings strongly support the principle of competitive exclusion, suggesting established lineages actively suppress competitors. While Oxford Nanopore sequencing offers necessary resolution for wildlife parasitology, fine-tuning algorithmic parameters is critical to accurately represent host-parasite networks and prevent the artificial inflation of intra-host diversity metrics. Author summaryPrevious studies using DNA metabarcoding have reported that wild mammals, such as bats, frequently harbor complex communities of multiple Trypanosoma parasite lineages simultaneously. However, ecological principles suggest that identical competitors struggle to coexist stably within a constrained environment like the host bloodstream. To investigate whether these reported high coinfection rates reflect true biology or methodological artifacts, we sequenced the 18S rRNA gene of Trypanosoma from 26 bats and 27 armadillos in Ecuador. We processed the sequencing data through computational pipelines with progressively stricter filtering parameters. We observed that under lenient filtering, animals appeared to have highly diverse, mixed infections. Conversely, when strict parameters were applied to remove potential analytical noise, the artificial complexity collapsed, revealing that the vast majority of hosts were dominated by a single parasite lineage. We confirmed only three active mixed infections in our highly restricted dataset. Our findings indicate that active multi-strain Trypanosoma coinfections are rare, aligning with the principle of competitive exclusion. These results highlight the necessity of applying rigorous bioinformatic filters to accurately evaluate host-parasite interactions and avoid overestimating diversity metrics.

The maned wolf (Chrysocyon brachyurus) is a near-threatened canid species that suffers from gastrointestinal (GI) disease under human care. While the cause remains poorly understood, recent studies report that altered gut microbiota is linked to GI disease in the domestic dog. The goal of this study was to describe the relationship between gut bacteria and environmental factors, GI health, short chain fatty acid (SCFA) peaks, and genetic relatedness in maned wolves. Fresh fecal samples were collected twice from wolves (first collection n = 29; second collection n = 25) housed in six facilities in the United States. Fecal alpha-1 proteinase inhibitor (FA1PI), a biomarker for GI health in canids, and SCFA peaks were quantified. Information on diet, housing group and history of GI disease or inflammation was provided by the zoological facility for each wolf. We characterized gut microbiota using 16S rRNA gene amplicon sequencing with qPCR abundance corrections. We found that dietary fiber gross energy (GE), protein GE, and number of daily produce items influenced gut microbiota. Additionally, there was a negative relationship between dietary fiber GE and Fusobacterium sp. abundance, corroborating previous findings linking fiber to altered gut microbiome composition in canids. Lastly, fiber GE was negatively correlated with FA1PI, connecting fiber to GI health in the maned wolf. Findings from this study suggest that increasing dietary fiber GE changes the gut microbiome and may improve GI health in the maned wolf, highlighting important management decisions that can be considered to maintain a healthy zoo-managed maned wolf population. IMPORTANCEFindings from this study are important because gastrointestinal disease is a common health concern for maned wolves under human care, and the causes are not well understood. The current study found that diet, especially the amount of fiber gross energy, can affect gut bacteria and may support better gastrointestinal health. Diet alterations could be a practical tool for zoos to support management of gastrointestinal health issues in maned wolves. These findings also show the importance of carefully managing diets for a near-threatened species, since better gastrointestinal health may improve overall health and well-being and support reproduction. More research is needed to determine the best amount and type of fiber, but our results provide foundational information for improving care and supporting healthy zoo-managed maned wolf populations.

The 2015-2016 Zika virus (ZIKV) epidemic revealed the potential of flaviviruses to emerge rapidly, cause severe disease, and affect pregnancy outcomes. In 2016, Spondweni virus (SPOV), the closest known relative of ZIKV, was detected in mosquitoes in Haiti, suggesting it may also have the potential to emerge in the Western Hemisphere. The risks that close relatives of ZIKV pose to pregnant individuals are not well understood. Previously, we showed that SPOV can cause fetal demise, placental pathology, and vertical transmission in a mouse model. Here we report SPOVs pathogenic potential in pregnant rhesus macaques. We inoculated four macaques with SPOV at gestational day 30 (early first trimester) and compared their viral loads and fetal outcomes with those of macaques infected in the first trimester with either African-lineage ZIKV (ZIKV-DAK) or an Asian-lineage ZIKV isolate from Puerto Rico (ZIKV-PR) in previous studies. Plasma viremia persisted 10-31 days in SPOV-inoculated dams, whereas viremia resolved within 10-17 days for ZIKV-DAK and 5-52 days for ZIKV-PR. Cesarean deliveries near term (gestational day 152-157) revealed no demise, premature birth, or gross abnormalities in fetuses of dams inoculated with SPOV or ZIKV-PR. In contrast, under near-identical conditions, all ZIKV-DAK-inoculated dams experienced fetal demise between 12 and 20 days post-inoculation. At cesarean section, we did not detect SPOV RNA above the limit of detection in maternal (e.g., spleen, liver), placental, or fetal tissues, in contrast to previous findings with ZIKV-PR. Histological analysis revealed mononuclear/lymphohistiocytic villitis in all placentas of SPOV-exposed macaques, along with other pathological changes in individual placentas. Our findings suggest that SPOV infection of macaques in early pregnancy may result in placental pathology without overt fetal harm. Our results suggest that flaviviruses in the Spondweni serocomplex, which includes ZIKV and SPOV, may vary in their pathogenic potential during pregnancy. Author SummaryZika virus (ZIKV) can cause fetal harm. Does this risk extend to its closest known relative, Spondweni virus (SPOV)? Should SPOV circulate in humans, what risks would it pose in pregnancy? SPOV can injure fetuses in immunocompromised mice, but the physiology of pregnancy in mice differs greatly from that of humans. We therefore infected pregnant rhesus macaques with SPOV during early gestation and compared maternal viremia, placental pathology, and fetal outcomes with macaques infected with African- or Asian-lineage ZIKVs at the same gestational age. All fetuses survived to near-term pregnancy, fetal tissues were negative for SPOV RNA, and fetal growth tracked within expected ranges. Nonetheless, all SPOV-exposed pregnancies showed placental injury, including mononuclear/lymphohistiocytic villitis and maternal vascular malperfusion. Despite the absence of detectable SPOV RNA in fetal tissues, SPOV RNA persisted at term in maternal-fetal interface tissues in two of four animals. These data indicate placental injury without detectable vertical transmission in this translational model. Our results suggest that SPOV and ZIKV display a wide range of risks to the developing fetus. Identifying viral and host factors that increase the potential for fetal harm will be important for assessing risks posed by emerging viruses in this family.

Valid animal models are needed to evaluate how age-related changes in kidney function influence healthspan. Aging marmosets frequently develop renal insufficiency with anemia and exhibit reductions in body mass and metabolic rate. However, it remains unclear which age-related changes predict survival and which thresholds indicate increased mortality risk. We prospectively evaluated age, body composition, resting energy expenditure, hematology, and blood chemistry as predictors of 3-year survival in female and male marmosets (n = 66), 2-16 years of age. Objectives were to identify prognostic markers, define high-risk thresholds, and to develop and test a composite risk-factor scale for mortality screening in captivity. A 10-variable model showed the best predictive performance in multivariable Cox proportional hazards modeling, and was retained for further analysis (concordance = 0.881, p < 0.001). ROC curves using Youdens Index and AUC identified high-risk thresholds for predictors in the multivariable model, and threshold-defined categories were evaluated by Kaplan-Meier survival analysis. The 10 binary risk-factors were combined into a composite scale scored from 0 to 10 and tested with Cox regression. The scale explained approximately 42% of variance in survival and each additional risk factor increased mortality risk 1.75-fold (95% CI: 1.43-2.14, p < 0.001). Marmosets with [&ge;]7 risk factors exhibited a 19-month reduction in survival, and this high-risk threshold predicted 3-year survival with 89.4% accuracy. Results support the scale as a screening tool for mortality risk and highlight the high prevalence of age-associated renal disease and anemia in marmosets.

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.

This study aimed to examine entomologists' perceptions of equity, inclusion, and exclusion within the discipline, identifying perceived challenges and proposed solutions for advancing equity in the field. The present study surveyed 47 self-identified entomologists living in the United States in 2023. Using a mixed-methods design, the study examined entomologists' perceptions of inclusion and exclusion within the discipline through qualitative and quantitative measures. Respondents highlighted needs for race-conscious funding opportunities, comprehensive inclusion efforts through geographically diverse outreach, and access to role models and mentors with similar identities to future entomologists. Findings are discussed in relation to a smaller 2013 study on recruitment and retention of entomologists of color, which offers preliminary historical context. The 2013 respondents emphasized intrinsic and age-based barriers to recruitment (e.g., lack of interest, limited K-12 outreach), the 2023 findings point toward structural inequities and retention needs (e.g., systemic exclusion). The 2013 comparison is interpreted as exploratory given differences in sample size and scope between the two studies. The 2023 study highlights evolving perceptions of persistent inequities in entomology and identifies opportunities to build a more inclusive and representative discipline.

Low protein (LP) diets improve metabolic health in rodents and humans. In rodents, LP diets are typically implemented by replacing protein with carbohydrates like sucrose or cornstarch, keeping diets isocaloric. However, humans can choose from many different types of carbohydrate, and how dietary carbohydrate quality - the precise composition of the dietary sugars - impacts the response to dietary protein remains largely unexplored. Here, mice were fed control (21% protein) or LP (7% protein) diets with four different carbohydrate sources: sucrose, a 1:1 glucose/fructose mixture, glucose, or fructose. While LP diets improved metabolic health across all groups in male mice, carbohydrate quality also significantly altered specific health outcomes, with fructose-fed mice having the lowest body weight and adiposity of all control diets. In female mice, responses to LP diets were influenced by carbohydrate quality, with certain sugars inducing a stronger metabolic response to LP diets than previously seen. Finally, in female APP/PS1 mice, a model of Alzheimer's disease, we find that although LP diets reduce A-beta; plaque burden irrespective of carbohydrate type, dietary sugar type does influence spatial memory. Together, these results demonstrate that while dietary protein is a critical determinant of metabolic and neurological health, carbohydrate quality influences these outcomes in a sex-specific manner.

Dominance hierarchies are a fundamental aspect of social organization, enabling animals to minimize aggression and optimize access to resources. Previous studies have highlighted the energetic and physiological demands of dominant status, as well as the behavioral flexibility required of subordinates to navigate these hierarchies. Despite advancements in automated behavior tracking, limitations persist in tracking fine-scale, real-time interactions within complex social environments. Here, we developed and validated a novel RFID-based system to continuously monitor dominance hierarchies in group-housed male mice over 10 days. This system enabled unbiased behavioral inference across light phases and revealed spatial and temporal patterns of dominance behavior undetectable through traditional live-scored methods. Automated tracking accurately identified alpha individuals and consistently inferred linear hierarchies across cohorts, with greater precision for higher-ranked individuals. Behavioral metrics, such as transition frequencies and proximity to food zones, were consistent with dominance driven activity. Hormonal analyses revealed that higher-ranked mice exhibited increased leptin and peptide YY, consistent with heightened activity and satiety signaling, while lower C-peptide levels reflected greater metabolic demands of dominance. Furthermore, dominance rank was associated with differences in light-dark activity, which were in turn related to circulating hormone profiles. This study demonstrates the utility of automated RFID tracking in capturing dominance hierarchies with temporal and spatial granularity, while revealing links between social rank, metabolic regulation, and activity patterns advancing our understanding of social behavior dynamics.

Operant paradigms are powerful tools to quantify motivation and reward. Traditionally, operant conditioning research has been limited to food and drug reinforcers. Recent advances in commercially available operant equipment, however, allow for the quantification of social motivation. These operant assays are an improvement over commonly used social preference tasks, as they enable direct measurement of the effort and motivation driving social behavior. Based on a design by Venniro et al. (2020), the MedPC social operant boxes modify the traditional operant box setup for social interactions. The experimental rat can lever-press to raise a door for an interaction with a target rat behind a porous barrier. These social operant boxes have been widely adapted to test social behavior in adult and adolescent rodents and investigate how a range of conditions (e.g. stress, drug taking, etc.) affect social motivation. However, there is a gap in assessing maternal motivation for pups during the postpartum period, despite ample evidence that postpartum social behavior is highly relevant for offspring health outcomes. Here, we detail 3D-printed modifications to the standard Med PC social operant boxes to adapt the social target chamber to safely house neonatal pups. We have also developed testing protocols to assess motivation during the limited postpartum period. These data demonstrate that, with simple modifications to social operant chambers and testing protocols, the field can implement advanced behavioral approaches to directly assess maternal motivation.

Protected areas are vital to the recovery of endangered species. Of the 24 remaining endemic passerines in Hawaii, 16 species are endangered or critically endangered. Yet protected areas in the archipelago are changing as a result of climate change and biological invasions. For example, the non-native southern house mosquito (Culex quinquefasciatus), the primary vector of avian malaria (Plasmodium relictum), has been encroaching upward as higher elevations warm. How the ranges of endemic birds have also shifted their range upward in the Ka[u] Rainforest, the largest native forest on the Island of Hawaii, is not well understood. We used hierarchical distance sampling to characterize how population density has changed from 2002 to 2024 for eight endemic bird species in the Ka[u] Rainforest. For five species, the most parsimonious model included an interaction between year and a quadratic elevation effect. Species that were most common at lower elevations in 2002, e.g., Apapane (Himatione sanguinea), tended to be most common at mid-elevations by 2024. Species that were already most common at higher elevations, such as Iiwi (Drepanis coccinea) and Hawaii [A]kepa (Loxops coccineus), tended to decline in density. For example, Iiwi density at 1,530 m declined from 3.31 birds per ha (95% confidence interval [CI]: 2.67-4.11) to 1.34 birds per ha (95% CI: 1.05-1.71), and Hawaii [A]kepa were completely extirpated from elevations below 1,530 m by 2024. Our results demonstrate how the elevational ranges of endemic species have shifted in response to climate change, biological invasions, and habitat degradation. Translating these results into conservation measures may require a more thorough investigation of the causal mechanisms of these range shifts with finer scale habitat data, under the same hierarchical modeling framework.

Social wasps (family: Vespidae) are increasingly concerning invaders and have been subject to increased detections and a growing number of invasive populations in the last few decades. As established invasive populations are challenging to eradicate, preventing introductions and prioritizing early interventions are the most cost-effective management solutions to mitigate these effects. A current challenge to this approach is that species distribution data is limited for many social wasp species, hindering our ability to accurately predict novel habitats with high suitability. To address this gap, we used MAXENT to create species distribution models (SDM) for 299 species of social vespid. We identified existing invasive populations of social wasps and incorporated their current invasive ranges to improve the transferability of our models in predicting habitat suitability in new environments. Current range sizes and habitat suitability varied widely among species and genera. We identified new species of high invasive concern, particularly in the genus Vespa. We also identified previously unrecognized regions that may be at high risk of future invasion primarily in Central Africa and the Indo-Australian Archipelago. Combining current and suitable ranges, we calculated an "Invasion Risk Score" to compare the relative likelihood of each species establishing a new invasive population based upon habitat suitability. To assess invasion risk in the future, we projected habitat suitability under four Shared Socioeconomic Pathway (SSP) climate change scenarios. Under all scenarios, species faced significant changes in habitat suitability for current native ranges. Habitat suitability generally shrank and shifted towards the poles, leaving equatorial species at highest risk of habitat loss. Notably, Vespa was the only genus whose suitable habitat expanded under these climate scenarios. Our framework demonstrates how multi-species SDMs can be applied to risk management of invasive populations.

Land-use change, such as the transformation of woody ecosystems into open pastures, acts as a strong ecological filter, favouring some species while excluding others according to differences in ecological niche breadth. Understanding how differences in niche breadth influence species responses under anthropogenic filters is crucial to anticipate their persistence or displacement. In this study, we quantified realized niche breadth in two sympatric ecosystem engineers, the Neotropical leaf-cutter ants Atta cephalotes and Atta laevigata, to test whether breadth differences are consistent with specialist and generalist ecological strategies. We characterized realized niche breadth across fine-scale environmental gradients by integrating hemispherical photography, microclimatic data, mound architecture, and edaphic profiles from 114 colonies across a regional transect in the Colombian Andes, alongside macroclimatic data from Copernicus. Principal Component Analysis (PCA) and PERMANOVA identified canopy openness and bushes- and tree-type vegetation density as the principal axes of interspecific niche partitioning. The observed differences in realized niche breadth were consistent with specialist and generalist ecological strategies. A. laevigata was predominantly associated with open-canopy areas, warmer micro- and macroclimatic conditions, and narrower edaphic dispersion. In contrast, A. cephalotes occupied a wider range of microhabitat conditions. This broader realized niche breadth is compatible with previous reports of A. cephalotes occurring in urban areas. Together, these findings suggest that niche breadth may influence how Neotropical leaf-cutter ants respond to habitat transformation, helping to understand the ecological consequences of land-use change.