Leukocyte profiles reflect geographic range limits in a widespread Neotropical bat

Corresponding Author: Daniel Becker, daniel.becker3@montana.edu

Why are some wildlife populations more or less susceptible or tolerant to infectious disease? Answering this question requires more broadly understanding how environmental variation shapes animal immune defense, but this is limited by the rarity of studies that apply a macroecological perspective to wildlife immunology and measure immune metrics across many populations of broadly distributed species. CEID member Daniel Becker and colleagues including CEID member Sonia Altizer conducted a comparative study of white blood cell profiles from 39 vampire bats (Desmodus rotundus). White blood cell profiles were highly predictable over space, with neutrophils and lymphocytes varying up to six-fold from populations spanning Mexico and Belize to Argentina and Uruguay. While blood cells were spatially autocorrelated at small and very large distances, suggesting that local environment and large-scale biogeographic factors influence cellular immunity. Generalized additive models confirmed that bat populations closer to the northern and southern limits of the range had more neutrophils, monocytes, and basophils, but fewer lymphocytes and eosinophils, than bats sampled at the core of their distribution. Their findings suggest that populations at the edge of their range may experience physiologically limiting conditions that predict higher stress and greater investment in cellular innate immunity. More broadly, this study suggests that systematically assessing immune function over space will elucidate how environmental conditions influence animals’ ability to resist infection and help predict disease risks with anthropogenic disturbance, land conversion, and climate change.

Becker, D.J. et al. (2019) Leukocyte profiles reflect geographic range limits in a widespread Neotropical bat. Integrative and Comparative Biology, icz007. https://doi.org/10.1093/icb/icz007

Photo Credit: “29/52-1: Common Vampire Bat” by Joy VanBuhler licensed under CC BY-NC-ND 2.0