Meeting Abstract
The population of Siberian hamsters (Phodopus sungorus) consists of individuals that differ in the response to seasonal changes. Responders, who are sensitive to shortening photoperiod, enter daily torpor in winter while non-responders remain normothermic throughout the year. We tested the hypothesis that these phenotypes differ in their behavior. We used 80 male and 80 female hamsters acclimated to winter-like conditions for 18 weeks. We also predicted that hamster behavior correlates with energy metabolism. To quantify behavior, we tested each hamster in an open field, and then measured its nest building activity. Both tests were repeated ten days apart. We used principal components analysis to define behavioral variables. Basal metabolic rate (BMR) was measured by indirect calorimetry and body temperature was monitored continuously with data loggers. Hamsters were classified into 3 phenotypes: those which entered torpor and changed fur to white were defined as responders, those which did not enter torpor and were gray were defined as non-responders, and those which only used torpor or only changed fur – as half-responders. Phenotype affected the difference between males and females in body mass-adjusted BMR (p<0.01); BMR of responding males tended to be higher than that of females, while among other phenotypes the opposite was true. We found a negative correlation between energy metabolism and exploration behavior (p<0.05) only among responders. This correlation supports the allocation model of the relationship between energy metabolism and activity in responders, but not in other phenotypes. The study was supported by the grant #NCN 2014/13/B/NZ8/04698.
