61-8 Sat Feb 27 13:00 – 13:15 Comparing thermal performance curves for metabolic rate, growth, and locomotion: evidence for tropical specialists and temperate generalists? Ghalambor, CK*; Shah, AA; Landeira-Dabarca, A; Rugenski, AT; Encalada, AC; Thomas, SA; Flecker, AS; Poff, NL; Norwegian University of Science and Technology and Colorado State University; University of Montana; Universidad San Francisco de Quito; University of Georgia; Universidad San Francisco de Quito; University of Nebraska; Cornell University; Colorado State University cameron.ghalambor@ntnu.no
A fundamental question at the interface of evolution and physiology is to understand how natural selection shapes the thermal sensitivity of traits. Gilchrist (1995) provided a model to explain how thermal performance curves should evolve under variable and constant environments. Here we compare thermal performance curves for metabolic rate, growth rate, and locomotor performance in temperate and tropical mayfly larvae from different elevations. Mayfly larvae from these sites differ in the amount of seasonal and daily temperature variation they experience. We found metabolic rate increased more quickly and growth rates to be lower in tropical compared to temperate species regardless of elevation. Locomotor performance did not show any clear differences except between low elevation species, where temperate species had broader thermal breadth compared to their tropical counterparts. We discuss these results in light of the assumptions and predictions put forward by Gilchrist (1995) and how they relate to the evolution of generalist-specialist continuum.
