Genetic variation in heat-stress tolerance among South American Drosophila populations

FALLIS, L; FANARA, JJ; MORGAN, T

GENETICA

SPRINGER

Lugar: Berlin; Año: 2011 vol. 139 p. 1331 - 1337

0016-6707

Spatial or temporal differences in environ-mental variables, such as temperature, are ubiquitous innature and impose stress on organisms. This is especiallytrue for organisms that are isothermal with the environ-ment, such as insects. Understanding the means by whichinsects respond to temperature and how they will react tonovel changes in environmental temperature is importantfor understanding the adaptive capacity of populations andto predict future trajectories of evolutionary change. Theorganismal response to heat has been identified as animportant environmental variable for insects that can dra-matically influence life history characters and geographicrange. In the current study we surveyed the amount ofvariation in heat tolerance among Drosophila melanogasterpopulations collected at diverse sites along a latitudinalgradient in Argentina (24–38S). This is the first study toquantify heat tolerance in South American populations andour work demonstrates that most of the populations sur-veyed have abundant within-population phenotypic varia-tion, while still exhibiting significant variation amongpopulations. The one exception was the most heat tolerantpopulation that comes from a climate exhibiting thewarmest annual mean temperature. All together our resultssuggest there is abundant genetic variation for heat-toler-ance phenotypes within and among natural populations ofDrosophila and this variation has likely been shaped byenvironmental temperature.