Abstract
During critical periods of food shortage or variable climatic conditions, the choice of an appropriate host can increase the survival and reproductive performance of parasites. In turn, one of the unique adaptations to periodical food shortages is hibernation, which is often found among insectivorous bat species in the temperate zone. While hibernating, bats are completely defenseless against both predators and ectoparasites, their immune and endocrine systems are diminished, and survival is dependent on the accumulated fat reserves. Differences in the health status or in the rate of consumption of the resources might also explain species-specific differences in ectoparasite abundance, especially between closely related host species, such as the greater mouse-eared bat (Myotis myotis) and the lesser mouse-eared bat (M. blythii) during hibernation. In the present study, the abundance of two ecologically distinct (summer and winter) types of ectoparasites was examined in terms of its influence on the body condition and hemoglobin content of the two host species. The effects of demographic factors, such as host sex and age, were also investigated. Despite a similar pattern of deteriorating body condition and hemoglobin concentration, M. myotis was more parasitized than was M. blythii. The marked decrease in hemoglobin content in first-year females of both host species correlated with the highest parasite load and indicated a risk of anemia. At the intraspecific level, ectoparasite abundance was not correlated with body condition (resources), but it negatively affected hemoglobin content; however, this mostly concerned M. blythii, which had a lower parasite load. Therefore, it can be concluded that interspecific differences in ectoparasite abundance may result from parasites selecting the host species that is less sensitive to their activity. In turn, in summer ectoparasites, the preference for female hosts is probably attributable to the likelihood of reinfection rather than to an effect of host resources or health status. The absence of sex-based preferences in winter ectoparasites could be explained by equal host availability.
Highlights
Non-random patterns of parasite abundance within a host species can be attributable to various extrinsic and intrinsic factors (Combes 2001)
In M. blythii, the seasonal effect was not significant, but near-significant differences were found for two interactions: between period and age and between sex and age
The body condition index of M. myotis was significantly higher in December than in April (p = 0.006, Table 1), adults were heavier than juveniles were (p < 0.0001, Table 1), and a nearly significant interaction was found between period and age (p = 0.091, Table 1): during hibernation, BCI decreased more in adult bats than in juveniles; no significant interactions were found (Table 1)
Summary
Non-random patterns of parasite abundance within a host species can be attributable to various extrinsic and intrinsic factors (Combes 2001). Parasite infestation may depend on the host’s health status (Christe et al 2003; Reckardt and Kerth 2009), sex (Morand et al 2004; Krasnov et al 2012) and age (Hawlena et al 2005). The host’s susceptibility to parasitism is influenced both by its resources and the function of its immune system. Host species exhibiting sex differences in terms of body condition often show concurrent sex-specific differences in parasite load. According to the vulnerable host hypothesis (Christe et al 2000), the sex with an inferior body condition may be more heavily parasitized. The well-fed host hypothesis explains a larger parasite load in one sex as resulting from
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
