Size matters: Host body mass overshadows climate change in parasite prevalence among semi-arid ground squirrels (Xerus inauris)

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Guarino, Andrea
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Climate change is a phenomenon in which global temperatures are rising, and animals respond by undergoing thermal stress, which may be linked to increased susceptibility to ectoparasites. Environmental temperature greatly influences ectoparasites as they rely on external heat sources to regulate their body temperature. This study investigated the effects of increasing maximum and minimum temperatures on ectoparasites abundance (number of parasites on an individual) and prevalence (number of infected individuals) of adult female African Cape ground squirrels (Xerus inauris). This study also investigated the effects of host body mass and host body condition on ectoparasite abundance and prevalence. We did not find a relationship between rising temperatures and ectoparasite loads (abundance and prevalence), nor did we find a relationship between body condition and ectoparasite loads. We speculate that the thermoregulatory behaviours of Cape ground squirrels mitigate ectoparasite loads. We did not find evidence for a relationship between host body mass and abundance; however, we found a significant negative relationship between host body mass and parasite prevalence. Our results show that a higher proportion of individuals are infected with fleas compared to lice. It remains uncertain whether the inverse relationship between host body mass and prevalence is due to increased skin strength or other traits in larger individuals. The different life history traits of the parasites could explain why fleas are more prevalent than lice. Fleas, being facultative parasites, can avoid the grooming behaviour of hosts. In contrast, lice, being obligate parasites, are bound to remain on their host, thus, are more vulnerable to being removed. As climate change persists, the host-parasite relationship between Cape ground squirrels and ectoparasites may be worth revisiting.
Ectoparasites, Xerus inauris, Climate change, African Cape ground squirrels