Bat cellular immunity varies by year and dietary habit in an increasingly fragmented landscape

Abstract

Monitoring the health of wildlife populations is essential in the face of increased agricultural expansion and forest fragmentation. Loss of habitat and habitat degradation can negatively affect an animal's physiological state, possibly resulting in immunosuppression and increased morbidity or mortality. We sought to determine how fragmentation may differentially impact cellular immunity and infection risk in Neotropical bats species regularly infected with bloodborne pathogens, and to evaluate how effects may vary over time and by dietary habit. We studied common vampire bats (Desmodus rotundus), northern yellow-shouldered bats (Sturnira parvidens), and Mesoamerican mustached bats (Pteronotus mesoamericanus), representing the dietary habits of sanguinivory, frugivory, and insectivory respectively, in northern Belize. We compared estimated total white blood cell counts, leukocyte differentials, and infection status with two blood-borne bacterial pathogens (Bartonella spp. and hemoplasmas) of 118 bats captured in a broadleaf, secondary forest over a three-year period (2017-2019) of increasing habitat fragmentation. We found evidence for bat species-specific responses of cellular immunity between years, with neutrophil counts increasing in D. rotundus, but decreasing in S. parvidens and P. mesoamericanus from 2018 to 2019. However, the odds of infection with Bartonella spp. and hemoplasma spp. between 2017 and 2019 did not differ between bat species, contrary to our prediction that pathogen prevalence may increase with increased fragmentation. We conclude that each bat species invested differently in cellular immunity in ways that changed over years of increasing fragmentation. We recommend further research on the interactions between habitat fragmentation, cellular immunity, and infection across dietary habits of Neotropical bats for informed management and conservation.

Serum proteomics reveals a tolerant immune phenotype across multiple pathogen taxa in wild vampire bats

“…As described previously ( 33 ), and as part of long-term studies of vampire bat diet, immunity, and infection ( 43 , 44 ), we captured 19 vampire bats in 2019 in the Lamanai Archeological Reserve in northern Belize using mist nests and a harp trap placed at a tree roost entrance. After recording morphometric data and sex, age, and reproductive status, we lanced the propatagial vein with a sterile 23G needle and collected blood into a serum separator tube (BD Microtainer) with a heparinized capillarity tube.…”

Expanded diversity of novel hemoplasmas in rare and undersampled Neotropical bats

“…The remaining six bat species were infected with novel genotypes in that host (i.e., host shifts or a new host-specific genotype) or represented the first hemoplasma detections for that species. For the former, we detected two genotypes in Dermanura phaeotis that were previously identified as specific to Carollia sowelli (CS1) and Sturnira parvidens (SP1, group B); the later genotype was also previously detected once in Artibeus lituratus [ 4 ], and we recently identified the group A variant in Pteronotus mesoamericanus [ 18 ]. Whereas the former four bat species belong to the family Phyllostomidae, Dermanura and Carollia belong to different subfamilies in that clade, suggesting inter-generic host shifts restricted by broader evolutionary history [ 4 ].…”