Effects of Ectoparasitism on Behavioral Thermoregulation in the Tropical lizards Anolis cybotes (Squamata: Dactyloidae) and Anolis armouri (Squamata: Dactyloidae)

Abstract

A febrile response, or a raised body temperature in response to infection, has been widely documented in various species of reptiles in laboratory trials. However, whether and how behavioral fever is achieved in nature remains almost entirely unknown. Here, we examine whether two species of lizard in the cybotoid clade of Hispaniolan trunk-ground anoles (Anolis cybotes and Anolis armouri) change their basking behavior in response to infestation by the chigger mite, Eutrombicula alfreddugesi. We examined body temperature and basking behavior in wild populations of A. cybotes and A. armouri from four localities that spanned a 2,000-m elevational transect in the Sierra de Baoruco, Dominican Republic. Although basking rate increased with elevation, we found that it did not correlate with mite load. Body temperature was also unrelated to parasite load. Thus, we found that E. alfreddugesi infestation did not induce behavioral fever in these anoles. We found a strong altitudinal pattern in chigger infestations: Infestations levels were highest in lizards from mid-elevation and dropped dramatically at low and high elevation (particularly in the latter). We discuss possible mechanisms for this altitudinal pattern in chigger infestation and discuss the relationship between infection and behavioral thermoregulation in lizards.