Desiccation resistance along an aridity gradient in the cactophilic fly Drosophila buzzatii: sex-specific responses to stress

PAOLA L. SASSI; ESTEBAN HASSON

EVOLUTIONARY ECOLOGY

SPRINGER

Año: 2012

0269-7653

Stress resistance characters are valuable tools for the study of acclimationpotential, adaptive strategies and biogeographic patterns in species exposed to environmentalvariability. Water stress is a challenge to terrestrial arthropods because of theirsmall size and relatively high area: volume ratio. Fruit flies have been investigated torecord adaptive morphological and physiological traits, as well as to test their responses tostressful factors. In this study, we investigate the ability to cope with water stress, byexamining variation in desiccation resistance in a species that lives mainly in desert lands.Specifically, we explored the genetic and ecological basis of desiccation resistance inpopulations of Drosophila buzzatii from Northern Argentina. We used a common gardenexperiment with desiccation treatments on a number of isofemale lines from four populationsalong an aridity gradient. Our results revealed significant among-population differentiationand substantial amounts of genetic variation for desiccation resistance. We alsodetected significant genotype-by-environment and genotype-by-sex interactions indicativethat desiccation resistance responses of the lines assayed were environment- and sexspecific.In addition, we observed clinal variation in female desiccation resistance alonggradients of altitude, temperature and humidity; that desiccation resistance is a sexuallydimorphic trait, and that sexual dimorphism increased along the aridity and altitudinalgradients. Based on current evidence, we propose that the observed sex-specific responses may reflect different life history traits, and survival and reproductive strategies in differentecological scenarios.