Reduced ectoparasite loads of deer mice in burned forest: From fleas to trees?

Abstract

Abstract. We tested whether reduced parasite loads might contribute to high post-fire abundances of deer mice (Peromyscus maniculatus). We performed parasite examinations of 54 mice captured in burned forest in the area of Davis Fire (western Montana, USA), and 26 mice captured in nearby unburned forest. Mean abundance of ectoparasites (fleas, ticks, and lice) was lower in burned than in unburned forest. The difference was particularly pronounced for fleas, which were reduced by 70% in burned forest. Endoparasites (i.e., nematodes and cestodes) were unaffected. Mechanisms for the lower mean abundance of fleas in burned areas are not known, but might involve flea mortality in burrows during fire or decreased transmission, survival, or both in the post-fire environment. We propose several hypothetical pathways through which reduced ectoparasite loads could cause an increase in deer mouse abundance, such as improved health status or increased foraging efficiency of mice, both of which could translate into the increased reproduction that has been reported in mice from burned forest. We encourage experimental tests of the ectoparasite release hypothesis of the post-fire increase in deer mouse abundance.

Ectoparasite burden influences the denning behavior of a small desert carnivore

“…Similar to the invasive species centered enemy release hypothesis (ERH), the ectoparasite release hypothesis (EPRH) predicts that a host species will benefit when ectoparasite enemies (e.g., native fleas) are no longer present or markedly reduced (Keane and Crawley , Zwolak et al. , Mlynarek ). While ERH has been widely studied (Colautti et al.…”

“…, Devevey and Christe ) or strictly observational in nature (Zwolak et al. ). Works on EPRH incorporating a known or assumed experimental reduction of ectoparasites under field conditions have occurred (Butler and Roper , Roper et al.…”

“…Consequently, additional manipulation‐based field investigations are needed to both gain a better general understanding of EPRH and elucidate the role ectoparasites can play on host individuals and populations (Zwolak et al. ).…”

“…Fleas are intermittent parasites, which can persist for an intermittent amount of time off their hosts under suitable environmental conditions (Zwolak et al. ), such as those provided by kit fox burrows (Salkeld et al. ).…”

“…Similar to the invasive species centered enemy release hypothesis (ERH), the ectoparasite release hypothesis (EPRH) predicts that a host species will benefit when ectoparasite enemies (e.g., native fleas) are no longer present or markedly reduced (Keane and Crawley 2002, Zwolak et al 2013, Mlynarek 2015. While ERH has been widely studied (Colautti et al 2004, Torchin and Lafferty 2009, Schultheis et al 2015, EPRH investigations are sparser, often laboratory-based (Hawlena et al 2006, Devevey et al 2008, Devevey and Christe 2009 or strictly observational in nature (Zwolak et al 2013).…”