PARASITISM BY MITES EUTROMBICULA ALFREDUGESI (TROMBICULIDAE) ON TWO SYMPATRIC SPECIES OF MABUYA (SAURIA: SCINCIDAE): THE EFFECT OF HABITAT ON PREVALENCE AND INTENSITY OF THE PARASITES

Abstract

We compared the patterns of ectoparasrtism by the chigger mite Eutrombicula alfredugesi (Trombiculidae) in two sympatric lizard species of the genus Mabuya (M. agilis, N=26; M. macrorhyncha, N= 72) in the Barra de Marica Restinga, which differ markedly in microhabitat use. We evaluated the prevalence and intensity of parasitism by the chigger mite in two lizard species, and we examined the microhabitats preferentially utilized by the chigger mites in the lizard body. Also, we studied the effect of lizard size and sex on the prevalence and intensity of infection by the chigger mites. The anterior armpits were the region of the lizard body that showed the highest intensity of infection. The mean intensity of infection of M. agilis was significantly higher than that of M. macrorhyncha (ANCOVA, F= 13.19, p< 0.001). The relationship between intensity of infection and lizard snout-vent-lenght was not significant in both species (M. agilis r = 0.15, p = 0.463; M. macrorhyncha, r = 0.002, p = 0.986) which indicates that in both species juveniles and adults are infected at similar rates and independent of body size. The monthly prevalence distribution did not differ significatively between the lizard species (Kolmogorov-Smirnov test, Dmax= 0.0214, p~ 0.679), indicating that the variation in the chigger mite prevalence throughout the year is similar in the two lizard species. On the other hand, the chigger mite intensity of infection differed markedly in the lizard species, being higher in M. agilis. The microhabitat preferred by M. agilis is the leaf litter on the ground where adults of the chigger mite can be found, while M. macrorhyncha preferentially uses bromeliads. The data suggest that the differences in intensity of infection between the lizard species probably result from different patterns of microhabitat use.