Female foraging strategy co-evolves with sexual harassment intensity in the Trinidadian guppy

Abstract Sexual harassment is a widespread evolutionary outcome of sexual conflict over mating rates. Male harassment can impose costs on females, and females often change their behaviors to avoid unwanted attention. In Trinidadian guppies (Poecilia reticulata), males use either sneak mating behavior or courtship displays as reproductive tactics. Both behaviors can be sources of sexual harassment, but sneak behavior is likely more harmful. Males adapted to low-predation habitats use more courtship and fewer sneak tactics than their high-predation ancestors. Here, we tested whether female foraging strategy co-evolves with less severe male harassment as guppies colonize low-predation environments. We set up outdoor stream mesocosms with common-garden-reared males and females from either a high- or a low-predation population in a 2 × 2 design, and tested whether populations diverge in female response to male harassment. We found that both sneak behavior and courtship display reduced female foraging, but the effect of sneak behavior was more extensive. Furthermore, the negative effect of sneak behavior was more pronounced on high-predation females. Our results suggest that female foraging strategy coevolved with divergence in male mating strategy: females under more severe sexual harassment evolved a foraging strategy that is more sensitive to varying harassment levels. Excessive male sexual harassment disrupts female foraging. Females should thus evolve strategies in response to varying harassment levels in order to improve foraging efficiency. Male guppies use either forced copulation or courtship displays as reproductive tactics; both behaviors influenced female foraging, but the effect of forced copulation was more severe. Females that evolve with higher levels of harassment were more sensitive to variations in male mating behavior, reducing their feeding more with increased harassment.