Jeanette Moss, Zachary Borthwick, Erik Wapstra, Geoffrey While

Global changes in temperature potentially influence sexual selection by restricting opportunities for activity. However, explicit tests of the behavioural mechanisms linking thermal variation to mating and reproductive performance are rare. We address this gap in a temperate lizard by combining social network analysis with molecular pedigree reconstruction in a large-scale thermal manipulation experiment. Populations exposed to a more restrictive (cooler) thermal regime presented fewer high activity days compared to populations exposed to a warmer regime. While plasticity in thermal activity responses masked overall differences in activity levels, prolonged restriction nevertheless affected the timing and consistency of male-female interactions. Less active females in the cool thermal regime were significantly less likely to reproduce, which subsequently limited male mating. Surprisingly, this did not correspond to a heightened intensity of sexual selection or shifts in the targets of sexual selection. Thus, populations facing thermal activity restriction may possess limited potential for evolutionary response.