Sprint speed is related to blood parasites, but not to ectoparasites, in an insular population of lacertid lizards

Parasites are able to negatively affect the locomotor performance of their hosts, and consequently, their biological fitness. In this study, we examine the relationship between parasitism and burst speed in an insular population of Lilford's Wall Lizard (Podarcis lilfordi (Günther, 1874)). Podarcis lilfordi is normally infected with haemogregarine blood parasites and mites in our study location, Aire Island (Balearic Islands, Spain). Unlike the results from other studies on lizards, we found a significant negative correlation between intensity of infection by haemogregarines and burst speed. Body condition is also significantly related to burst speed. Thus, lizards with a lower blood parasite load and better body condition show a faster sprint speed. Intensity of infection by haemoparasites shows a lack of correlation with both body condition and mite load. Our results are compared with those from other lizard species living in different habitats. We discuss the influence of insular environmental conditions on locomotor performances, such as low predation pressure, lack of competitors, and high lizard densities.