Parting ways: parasite release in nature leads to sex‐specific evolution of defence

Abstract

We evaluated the extent to which males and females evolve along similar or different trajectories in response to the same environmental shift. Specifically, we used replicate experimental introductions in nature to consider how release from a key parasite (Gyrodactylus) generates similar or different defence evolution in male vs. female guppies (Poecilia reticulata). After 4-8 generations of evolution, guppies were collected from the ancestral (parasite still present) and derived (parasite now absent) populations and bred for two generations in the laboratory to control for nongenetic effects. These F2 guppies were then individually infected with Gyrodactylus, and infection dynamics were monitored on each fish. We found that parasite release in nature led to sex-specific evolutionary responses: males did not show much evolution of resistance, whereas females showed the evolution of increased resistance. Given that male guppies in the ancestral population had greater resistance to Gyrodactylus than did females, evolution in the derived populations led to reduction of sexual dimorphism in resistance. We argue that previous selection for high resistance in males constrained (relative to females) further evolution of the trait. We advocate more experiments considering sex-specific evolutionary responses to environmental change.

Parallel and nonparallel behavioural evolution in response to parasitism and predation in Trinidadian guppies

“…Such sex‐specific behavioural responses might be due to the sex‐specific payoff functions associated with risk (Laland & Reader, ; Reader, ) and the fact that males are more willing than females to incur the risk associated with seeking additional mating opportunities (Magurran & Seghers, ). More attention should be paid to the differential evolutionary responses of males and females to the same environmental differences, as previously suggested for other guppy traits (Hendry et al ., ; Dargent et al ., ).…”

The influence of slavemaking lifestyle, caste and sex on chemical profiles in Temnothorax ants: insights into the evolution of cuticular hydrocarbons

“…Only slavemaker workers and queens interact with hosts, which led us to expect a signal of parasitic lifestyle to be present only in females, especially because parasite pressure on one sex can lead to sex-specific adaptations [75]. However, the characteristic chemical composition of slavemakers was especially pronounced in workers and males.…”

A Data-Validated Host-Parasite Model for Infectious Disease Outbreaks

“…However, sensitivity analysis of our generic outbreak magnitudes and periods consistently demonstrate that parasite virulence and parameters relating to guppy immunity have the strongest impact on our system and therefore this result was not an artifact of our experimental design. Both guppy resistance (Van Oosterhout et al, 2003;Dargent et al, 2016), and parasite virulence (Cable and van Oosterhout, 2007) are known to evolve rapidly and vary widely among populations due to different selective pressures and our findings indicate that understanding this heterogeneity is of significance to predicting and controlling disease outbreaks.…”