Thermal physiology of native cool-climate, and non-native warm-climate Pumpkinseed sunfish raised in a common environment.
Contemporary evolution of thermal physiology has the potential to help limit the physiological stress associated with rapidly changing thermal environments; however it is unclear if wild populations can respond quickly enough for such changes to be effective. We used native Canadian Pumpkinseed (Lepomis gibbosus) sunfish, and non-native Pumpkinseed introduced into the milder climate of Spain ~100 years ago, to assess genetic differences in thermal physiology in response to the warmer non-native climate. We compared temperature performance reaction norms of two Canadian and two Spanish Pumpkinseed populations born and raised within a common environment. We found that Canadian Pumpkinseed had higher routine metabolic rates when measured at seasonally high temperatures (15°C in winter, 30°C in summer), and that Spanish Pumpkinseed had higher critical thermal maxima when acclimated to 30°C in the summer. Growth rates were not significantly different among populations, however Canadian Pumpkinseed tended to have faster growth at the warmest temperatures measured (32°C). The observed differences in physiology among Canadian and Spanish populations at the warmest acclimation temperatures are consistent with the introduced populations being better suited to the warmer non-native climate than native populations. The observed differences could be the result of either founder effects, genetic drift, and/or contemporary adaptive evolution in the warmer non-native climate.
Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada K9L 0G2. Electronic address: annarooke@trentu.ca.
Anna C
AC
Rooke
Department of Biology, Trent University, Peterborough, Ontario, Canada K9L 0G2.
Gary
G
Burness
Department of Biology, Trent University, Peterborough, Ontario, Canada K9L 0G2; Environmental and Resource Studies Program, Trent University, Peterborough, Ontario, Canada K9L 0G2.
Michael G
MG
Fox
D000064:Acclimatization; D000818:Animals; D049628:Body Size; D001831:Body Temperature; D003080:Cold Temperature; D058865:Introduced Species; D010473:Perciformes / Q000254:growth & development / Q000502:physiology*
Climate change; Countergradient variation; Fish; Invasive species; Thermal adaptation