Alternative reproductive tactics

I am interested in the evolution and maintenance of alternative reproductive tactics. My main study system for my PhD was the unique and intriguing ocellated wrasse (Symphodus ocellatus)! In this species there are three distinct male morphs: (1) nesting males, (2) satellite males, and (3) sneaker males. Females have a strong preference for nesting males who provide all the parental care. Sneaker males will try to sneak in during matings. Satellite males help nesting males chase away sneakers, but when given the opportunity will also try to sneak spawns. During my dissertation, I investigated how sneakers and satellite males differ in sneaking delays and how the social environment influence sneaking delays. We found that satellites have shorter sneak-spawning delays than sneakers, a benefit of their cooperation with nesting males. Sneak-spawning delays decreased with increasing nest activity for sneakers but not for satellites, suggesting that sneakers may, counter intuitively, benefit from increased sperm competition intensity (Kustra et al. 2023 Am. Nat.). I conducted follow up fertilization experiments to see how female reproductive fluids influence the timing of fertilization and selection on male sneaking delays. This work is still in progress.

Most recently, I published (a quick guide (mini review) on male alternative reproductive tactics(Kustra and Alonzo 2025 Curr. Biol.). I have also published a review on the evolution of sperm traits in species with alternative reproductive tactics (Kustra and Alonzo 2020 Philos. Trans. R. Soc. B. ). We specifically reviewed theoretical predictions on how male alternative reproductive tactics should differ in sperm quality. Despite general expectations that sneaker males should have higher sperm quality, existing theory does not make explicit predictions on how males adopting ARTs should differ in sperm traits. When we look at empirical studies, the majority of studies find no significant difference in sperm performance traits between dominant and sneaker males.