Remnant fragments within an agricultural matrix enhance conditions for a rodent host and its fleas

Habitat fragmentation can adversely impact biodiversity, although where remnant fragments of natural vegetation provide favourable conditions the negative effects of fragmentation may be mitigated. Host-parasite systems in fragmented areas have only recently been examined, with parasites generally showing higher prevalence and richness in fragments, mediated by changes in host density. However, the effect of fragmentation on parasite body size and fecundity remains poorly investigated. Thus, here we compared the body size and condition of a generalist rodent host, Rhabdomys pumilio and the body size of 2 common flea species between pristine natural areas and remnant fragments within agriculture areas. Host body length, weight and body condition values were significantly larger in fragments than in pristine natural vegetation. Listropsylla agrippinae fleas showed the same pattern, being significantly larger in fragments, while Chiastopsylla rossi fleas did not differ in size between fragments and natural areas. The differential response of the 2 flea species may reflect the strength of association between the host and parasite, with the former spending a greater proportion of its lifespan on the host. Therefore, in this study agriculture fragments provide better conditions for both an opportunistic rodent and a closely associated flea species.