Biology subjects

Bastille-Rousseau, G.

Publications and source records attributed to Bastille-Rousseau, G..

4 recordsLinked to original sources

bioRxiv2026

Gray fox (Urocyon cinereoargenteus) survival in southern Illinois, USA

Gray fox (Urocyon cinereoargenteus) populations in the Midwestern USA have suffered precipitous declines in recent decades, yet they are relatively understudied. However, understanding survival and cause-specific mortality is vital for declining populations and the limited existing survival studies have been performed outside of the Midwest. We equipped 13 gray foxes in southern Illinois with GPS radio collars to investigate their survival and cause-specific mortality. We calculated the Kaplan-Meier 6- and 12-month survival rates to be 0.79 (95% CI: 0.57-1.0) and 0.53 (95% CI: 0.27-1.0), respectively. We recorded 4 mortalities: 1 disease, 1 gunshot, and 2 unknown causes. While our study has a small sample size, it contributes key information on a data-deficient mesocarnivore suffering from a population decline driven by undefined causes. We recommend further research into the survival and mortality of this elusive mesocarnivore.

ecology↗

bioRxiv2026

Widespread occurrence of bovine-like and new viruses in wild deer across the United States

Over the past several decades, deer populations in North America have grown considerably, resulting in frequent contact with humans and livestock, and increased potential for pathogen spillover. Despite the importance of pathogen spillover among humans, wildlife, and livestock, the diversity of viruses present in deer remains largely unknown. Using a metagenomic high-throughput sequencing approach, we characterized viral communities in the upper respiratory tracts of live mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus) captured at fourteen study sites in nine states across the United States. We identified vertebrate-infecting viruses in both deer species at all but two of the study sites, located in Illinois and Utah. Viral richness did not vary among species or study sites. However, viral community composition was different across study sites but not among deer species. Amongst the detected viral sequences, several originate from or were closely related to viruses previously described in humans (e.g., severe acute respiratory syndrome coronavirus 2) and livestock (e.g., bovine-like coronavirus). We also documented viruses recently discovered in deer, such as CHeRI orbivirus 1. Finally, we identified several new putative viruses in the Picornaviridae, Rhabdoviridae and Tobaniviridae families, including a novel Aphthovirus related to bovine rhinitis A virus in both deer species, across seven states and nine study sites. Our findings expand the understanding of viral diversity in two deer species across the United States, providing important insights for managing pathogens at the wildlife, livestock, and human interface.

microbiology↗

bioRxiv2026

Drivers of mosquito free-flight and resting behavior indoors

Mosquito flight and resting behaviors mediate pathogen transmission and vector control success, yet their environmental and genetic determinants remain poorly understood. We combined novel high-resolution 3D tracking with factorial semi-field experiments in Merida, Mexico, to quantify how endogenous traits (strain, sex, physiological state) and exogenous conditions (microclimate, visual cues) influence the flight and resting behavior of Aedes aegypti, the primary vector of Dengue, Zika, and Chikungunya. Mosquitoes with a Wild-type genetic background flew and rested at lower heights than mosquitoes from with a laboratory strain background. Such difference was not explained by microclimate, with progeny from reciprocal cross experiments demonstrating wild-type-like behavior, which suggest a potentially heritable behavioral divergence. Microclimatic (temperature and relative humidity) gradients differed across time and height, with estimated Vapor Pressure Deficits (VPDs) indicating that mosquitoes adjusted flight height to minimize desiccation risk. However, this microclimatic influence was overridden by presence of black surfaces, which strongly attracted mosquitoes to rest, even if such resting heights had unfavorable conditions. These findings reveal a trade-off between visual, genetic, and microclimatic drivers of behavior which have important influence in the design and impact of vector control interventions. Significance StatementThis study integrates high-resolution, three-dimensional mosquito tracking with analogue sticky traps and mathematical modeling to understand innate free-flight and resting behavior of indoor-dwelling mosquitoes. Factorial semi-field experiments conducted in Merida, Mexico, demonstrate that wild and laboratory mosquito strains differ markedly in flight and resting preferences. By quantifying microclimatic gradients and vapor-pressure deficits, we show mosquitoes may dynamically adjust their vertical position to minimize desiccation risk, however, presence of strong visual cues can override these microclimatic constraints. Together, we demonstrate a mechanistic framework that links genetics, physiology, and environment to explain Ae. aegypti behavior indoors.

ecology↗

bioRxiv2021

Accounting for animal movement improves vaccination strategies against wildlife disease in heterogeneous landscapes

Oral baiting is used to deliver vaccines to wildlife to prevent, control, and eliminate infectious diseases. A central challenge is how to spatially distribute baits to maximize encounters by target animal populations, particularly in urban and suburban areas where wildlife like raccoons (Procyon lotor) are abundant and baits are delivered along roads. Methods from movement ecology that quantify movement and habitat selection could help to optimize baiting strategies by more effectively targeting wildlife populations across space. We developed a spatially explicit, individual-based model of raccoon movement and oral rabies vaccine seroconversion to examine whether and when baiting strategies that match raccoon movement patterns perform better than currently employed baiting strategies in an oral rabies vaccination zone in greater Burlington, Vermont, USA. Habitat selection patterns estimated from locally radio-collared raccoons were used to parameterize movement simulations. We then used our simulations to estimate raccoon population rabies seroprevalence under currently used baiting strategies (actual baiting) relative to habitat selection-based baiting strategies (habitat baiting). We conducted simulations on the Burlington landscape and artificial landscapes that varied in heterogeneity relative to Burlington in the proportion and patch size of preferred habitats. We found that the benefits of habitat baiting strongly depended on the magnitude and variability of raccoon habitat selection and the degree of landscape heterogeneity within the baiting area. Habitat baiting improved seroprevalence over actual baiting for raccoons characterized as habitat specialists but not for raccoons that displayed weak habitat selection similar to radio-collared individuals--except when baits were delivered off roads where preferred habitat coverage and complexity was more pronounced. In contrast, in artificial landscapes with either more strongly juxtaposed favored habitats and/or higher proportions of favored habitats, habitat baiting performed better than actual baiting, even when raccoons displayed weak habitat preferences and where baiting was constrained to roads. Our results suggest that habitat selection-based baiting could increase raccoon population seroprevalence in urban-suburban areas, where practical, given the heterogeneity and availability of preferred habitat types in those areas. Our novel simulation approach provides a flexible framework to test alternative baiting strategies in multiclass landscapes to optimize bait distribution strategies.

ecology↗