Elevated temperature changes female costs and benefits of reproduction

Despite obvious benefits, reproduction also imposes severe costs on females. Such costs and benefits are highly sensitive to environmental factors. Rapidly changing conditions may thus disturb a finely poised balance between the two and pose a challenge to natural populations. A more complete understanding of reproduction and population fitness across different environments is, hence, crucial. In particular, sexual selection could either be beneficial or detrimental when conditions change abruptly. Here Tribolium castaneum females were subjected to mating treatments with or without sexual selection (virginity, monogamy, polyandry) replicated at standard versus elevated temperatures. We found a substantial survival cost of reproduction at the standard, but not at the elevated temperature. Reproductive success was similar across mating treatments at the standard temperature, but at elevated temperature we detected a significant benefit of polyandry compared to monogamy. These findings indicate that environmental heterogeneity can strongly influence the balance between costs and benefits when sexual selection is allowed to act. Furthermore, reproduction may be critically affected by changes in temperature with potentially profound consequences for population fitnes