Field trial of a probiotic bacteria to protect bats from white-nose syndrome

Joseph R Hoyt,Jeffrey T Foster,A Marm Kilpatrick,Katy L Parise,Winifred F Frick,Jennifer A Redell,Kate E Langwig,J Paul White,Heather M Kaarakka

doi:10.1038/s41598-019-45453-z

Abstract

Tools for reducing wildlife disease impacts are needed to conserve biodiversity. White-nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans, has caused widespread declines in North American bat populations and threatens several species with extinction. Few tools exist for managers to reduce WNS impacts. We tested the efficacy of a probiotic bacterium, Pseudomonas fluorescens, to reduce impacts of WNS in two simultaneous experiments with caged and free-flying Myotis lucifugus bats at a mine in Wisconsin, USA. In the cage experiment there was no difference in survival between control and P. fluorescens-treated bats. However, body mass, not infection intensity, predicted mortality, suggesting that within-cage disturbance influenced the cage experiment. In the free-flying experiment, where bats were able to avoid conspecific disturbance, infection intensity predicted the date of emergence from the mine. In this experiment treatment with P. fluorescens increased apparent overwinter survival five-fold compared to the control group (from 8.4% to 46.2%) by delaying emergence of bats from the site by approximately 32 days. These results suggest that treatment of bats with P. fluorescens may substantially reduce WNS mortality, and, if used in combination with other interventions, could stop population declines.

Highlights

White-nose syndrome (WNS), caused by the introduced fungal pathogen, Pseudogymnoascus destructans, has caused widespread declines in bat populations throughout eastern and central North America and threatens several species with extinction[1,2,3,4,5,6]
The fraction of bats known to be alive and detected by the passive integrated transponder (PIT) tag reader after March 8 was 46.2% (6/13) for P. fluorescens-treated bats, which was significantly higher than 8.5% (1/12) for control bats (Fig. 3; the remaining 7 bats had lost their PIT tag; see Methods)
Our results suggest that P. fluorescens could be a useful tool for reducing WNS impacts on bat populations, especially if treatment efficacy could be improved

Summary

Introduction

White-nose syndrome (WNS), caused by the introduced fungal pathogen, Pseudogymnoascus destructans, has caused widespread declines in bat populations throughout eastern and central North America and threatens several species with extinction[1,2,3,4,5,6]. In the free-flying experiment, we treated bats and attached a passive integrated transponder (PIT) tag to each bat to determine the date it emerged from the site. This experiment allowed bats to move freely throughout the site and roost wherever they chose. Bats might die at the site and be eaten by predators, escape from the site by an unknown exit and not be detected by the PIT tag receiver, or move to another site midwinter and survive at that site To balance these unknowns, we performed an experiment with bats in cages. Caging bats alters their behavior (e.g. bats cannot select their roosting location and microclimate, and bats in the same cage may be disturbed when other bats arouse from hibernation20), and placing all bats in a treatment within a single cage results in pseudo-replication

Objectives

Methods

Results

Conclusion