Spatial, Temporal, and Host-Specificity Patterns of Three Genera of Blood Coccidian Parasites in Two Syntopic Mediterranean Lizards.

We investigated the phenological variation of three genera of blood parasites of lizards (Schellackia, Karyolysus, and Lankesterella) using samples of 275 adult Psammodromus algirus and 138 Acanthodactylus erythrurus collected from April to September in 2021 and 2022. Both years experienced heatwaves, and 2022 had the warmest summer on historical record for the region. We captured lizards in two close areas that differed in vegetation quality due to differential human pressure. We found that Schellackia and Karyolysus more frequently infected P. algirus, whereas Lankesterella infected A. erythrurus. We fitted generalized additive models to explain parasite intensity, including the non-linear effect of phenology sorted by sex and the linear effects of body length, body condition, host sex, heterophil-lymphocyte ratio, distance to a road, and microclimate. We found a positive effect of body length on parasite intensity across parasite genera. The intensity of Schellackia was higher in female hosts, contradicting the dogma of higher male susceptibility to infections. The intensity of Lankesterella was lower closer to the road, indicating that parasite transmission success can vary at the microgeographic scale. We found a non-linear significant increase of Karyolysus across the activity period, suggesting a relaxation of the antiparasitic control upon this genus toward the end of the activity period. For Lankesterella, we observed a phenological increase only in female lizards, suggesting sexual differences in immunocompetence. We found higher intensity of Karyolysus and Lankesterella in 2022, conforming to the idea that heat waves may impair lizards' immunocompetence.