Eimeria-parasites are associated with a lowered mother's and offspring's body condition in island and mainland populations of the bank vole

Abstract

This study, based on correlative data, tests the hypothesis that infections with Eimeria spp. parasites exert a significant loss of fitness of bank voles (Clethrionomys glareolus) reflected in lower reproductive success and survival, declining host population densities and are associated positively with population size. The study was conducted in 20 mainland and 27 island populations in central Finland during May-September in 1999. Faecal samples showed that 28% of 767 individuals were infected with Eimeria spp. The presence of Eimeria parasites was higher in dense mainland populations than in sparsely populated islands. Eimerian infections increased during the course of the breeding season, probably as a result of the high infection rate of young individuals. Accordingly, the body masses of bank voles were negatively related to the presence of Eimeria spp. Reproductive output, as measured by the breeding probability of females and litter size, was not associated with the presence of eimerian infection. Interestingly, the body condition of the infected mothers appeared to be low. Moreover, mother's body condition was the single most important variable studied that showed a positive correlation to pup's body condition at birth. On small islands (< or =3.2 ha) that were comprehensively trapped, the mean number of Eimeria spp. in the bank vole population was negatively related to density changes of the bank vole population during the study. Our data are consistent with the idea that infection with coccidian parasites may be one of the factors responsible for declining host populations in small, isolated populations.

Condition, innate immunity and disease mortality of inbred crows

“…Although a link between condition and disease is not unexpected (Beldomenico et al 2008), field studies that document this link in wild populations are rare (e.g. Hakkarainen et al 2007;Beldomenico et al 2009). Effects of poor condition and infection can be synergistic, because individuals in poor condition might be less resistant to disease, and infection might further reduce individual condition (Beldomenico et al 2008).…”

Diseases and reproductive success in a wild mammal: example in the alpine chamois

“…A reduction in fecundity in parasitized hosts was reported in several studies of endemic microparasites in wildlife (Phillips 2000; Lello et al 2005;Telfer et al 2005;Hakkarainen et al 2007). Chlamydia pecorum infection, which causes reproductive-tract infections in koalas Phascolarctos cinereus, may limit the reproductive potential of populations (Phillips 2000).…”

“…Finally, by decreasing individual body condition, which is generally related to number or body condition of oVspring, parasites decrease oVspring quality and recruitment in infected populations. Hakkarainen et al (2007) demonstrated that the body mass of bank voles was negatively related to the presence of Eimeria spp., an intestinal protozoan frequently documented in rodents (Laakkonen et al 1998). Mothers infected by Eimeria spp.…”

The effects of mite parasitism on the reproduction and survival of the Taiwan field mice (Apodemus semotus)

“…Parasites can alter host physiology (Schall et al 1982;Simon et al 2004), body condition (Hakkarainen et al 2007;Vandegrift et al 2008;Turner et al 2012), behavior (Schall et al 1982;Goodman and Johnson 2011), social dominance (Schall and Houle 1992;Zohar and Holmes 1998), and life history (Schall 1983;Schall and Dearing 1987;Shields and Wood 1993;Merino and Potti 1995;Lochmiller and Deerenberg 2000;Skarstein et al 2001;Chadwick and Little 2005;Cox and John-Alder 2007;Kallio et al 2007), leading to complex ecological and evolutionary consequences in host populations (Hamilton and Zuk 1982;Buckling and Rainey 2002;Chadwick and Little 2005). Theoretical and field studies suggest that parasites can regulate host populations, playing a role comparable to predators (May and Anderson 1979;Albon et al 2002;Redpath et al 2006;Lemaître et al 2009).…”