Hawaiian picture wing Drosophila sproati exhibit adaptive population divergence along a narrow climatic gradient on Hawaii Island

D. grimshawi microarray used to text for gene expression differences between two populations subjected to control or low-intensity heat for one week during maturation Anthropogenic influences on global processes and climatic conditions are increasingly affecting ecosystems throughout the world. Hawaii Island’s native ecosystems are well-studied and local long-term climatic trends well-documented, making these ecosystems ideal for evaluating how native taxa may respond to a warming environment. This study documents adaptive divergence of populations of a Hawaiian picture wing Drosophila, D. sproati, that are separated by only 7km and 365m in elevation. Representative laboratory populations show divergent behavioral and physiological responses to an experimental low-intensity increase in ambient temperature during maturation. The significant interaction of source population by temperature treatment for behavioral and physiological measurements indicates differential adaptation to temperature for the two populations. Significant differences in gene expression among males were mostly explained by the source population, with eleven genes in males also showing a significant interaction of source population by temperature treatment. The combined behavior, physiology, and gene expression differences between populations illustrates the potential for local adaptation to occur over a fine spatial scale and exemplifies nuanced response to climate change. 44 Drosophila sproati flies from low- and high-elevation populations were raised for six generations in a controlled climate. During the 6th generation each population was split into two groups, one held at the control 18C, and the other group expoosed to 24C during their 3rd week of maturation. Gene expression was measured at week four.