Seasonal challenges of tropical bats in temperate zones

Abstract

To examine the challenges faced by free-ranging Rousettus aegyptiacus living at the northern edge of their distribution, we performed a retrospective analysis of 2196 clinical cases reported by a bat rescue NGO over a period of 36 months, from throughout Israel. All cases of injured bats were evaluated and categorized according to date, place, sex, age, and etiology of the morbidity. The data analysis revealed an increase in all types of morbidity during the wintertime, with more than two-fold the number of cases per week compared to in the summer, over three consecutive years. Moreover, we found that the number of abandoned pups peaked during spring and summer, when adult morbidity is minimal. We characterized two prominent types of previously undescribed morbidities in R. aegyptiacus. We also employed GPS tracking to monitor the movement and foraging of dozens of bats, and to examine the potential correlates of elevated winter morbidity. Our results suggest that it is mainly harsh weather that drives the observed winter morbidity, with food limitations playing a minor-role. We hypothesize that R. aegyptiacus, of tropical origin, is facing major seasonal survival difficulties near the northern edge of its distribution, probably limiting its spread further northwards still.

Hibernating vesper bats are a weak source for biomonitoring of coronaviruses

“…The number contrasts with findings in northern Germany, relatively closer to our study area, where bats caught outside the shelter during their activity period showed higher coronavirus prevalence [ 25 ]. The low prevalence in the colony studied here might be due to unfavorable physiological and behavioral conditions during bats' hibernation period, including a drop in bat's heart rate from 200 to 300 beats per minute to as low as 10 beats per minute and suspension of breathing for several minutes at a time, which might affect viral replication and reduce bats overall mobility and interactions, thereby decreasing the probability of virus transmission [ 27 ]. Contrary to our results, Subudhi et al (2017) found coronavirus persistence for up to 4 months in North American little brown bats during hibernation in laboratory settings [ 22 ].…”

Future climatically suitable areas for bats in South Asia

“…Yearly and seasonal patterns in temperature and precipitation, referred to in biogeographic modelling as bioclimatic factors or predictors, are known to influence behaviour and life history in bats around the world (Conenna et al., 2019 ; Gorman et al., 2021 ; Kohyt et al., 2021 ; Weinberg et al., 2022 ). To capture these conditions and test the hypothesis that macroclimatic effects can determine occurrence of bats, the 19 standard current bioclimatic predictor variables were sourced at 2.5 arc‐minute resolution from the WorldClim v2.1 database for the period of 1970–2000 (Fick & Hijmans, 2017 ).…”