S6-1.3 Sunday, Jan. 6 Global climate change leads to natural selection on the physiological mechanisms underlying seasonal timing VISSER, M.E.*; SCHAPER, S.V.; CARO, S.P.; Netherlands Institute of Ecology (NIOO-KNAW); Netherlands Institute of Ecology (NIOO-KNAW); Netherlands Institute of Ecology (NIOO-KNAW) email@example.com
Animals need to use information from their environment, so called cues, to accurately time their seasonal behaviours. These cues should be predictive for the time when conditions will be favourable for reproduction, moult, migration or other energy-demanding life-history stages. Due to global climate change however, the predictive value of the cues have been modified. As animals continue to use these cues in as in the past, their seasonal behaviour has become mismatched with their altered environment. This will lead to selection on how animals convert cues into seasonal behaviour, i.e. there will be selection on the underlying physiological mechanisms. To understand how natural selection may change the way cues are perceived and transduced, we not only need to understand how these physiological mechanisms function, but we also need to know where in these mechanisms the genetic variation lays. To forecast genetic change we also need to measure selection on the mechanisms in the wild. We will illustrate this conceptual framework with our work on great tits (Parus major), a small insectivorous bird. We studied the physiology and genetic background in 36 climate controlled aviaries and we measured selection in our long-term wild population. We show that the birds use increasing temperatures, rather than temperature per se, as a cue and that there is genetic variation in how cues are converted in timing of breeding (egg laying date). Gonadal development on the other hand is not affected by temperature, possibly constraining the advancement of laying dates in the wild. Integrative studies like these are essential to forecast the impact of future climate change on animals.