Claudia Londoño-Nieto, Michael Butler, Roberto García-Roa, Pau Carazo 

Sexual selection often leads to sexual conflict via pre-copulatory (harassment) and/or copulatory (traumatic insemination) male harm to females, impacting population growth, adaptation and evolutionary rescue. Male harm mechanisms are diverse and taxonomically widespread, but we largely ignore what ecological factors modulate their diversification.  Here, we conducted experimental evolution under cold (20±4ºC), moderate (24±4ºC) and hot (28±4ºC) thermal regimes in Drosophila melanogaster, a species with intense male harm via harassment and “toxic” seminal fluid proteins (SFPs), to show that temperature drives the divergent evolution of sexual conflict. At cold temperatures, evolution resulted in reduced and less plastic harassment (i.e. pre-copulatory harm) while, at warm temperatures, it was characterized by responses in the seminal proteome driven by differential expression of SFPs.  Our results show that temperature can be key to understand the past diversification and future (global warming) evolution of sexual conflict, and the maintenance of genetic variation in male harm traits.