SPERM-MEDIATED PATERNAL EFFECTS
Genetic change via evolution takes many generations, but in a changing environment, it is advantageous for parents to plastically respond to their current environment and produce offspring with phenotypes that match current environmental demands. It has been well-documented that maternal experiences (e.g. predation risk) prior to fertilization have a strong influence on offspring behavior and physiology. However, it has recently become clear that paternal experiences can have similar consequences for offspring, although the mechanisms underlying the transmission of paternal experiences are still not well understood. I am using threespined sticklebacks (Gasterosteus aculeatus) to understand how paternal experiences with predation risk prior to fertilization are transmitted to offspring via modifications to sperm, whether these paternal effects are distinct from maternal effects, and the mechanisms underlying these paternal effects.
Male stickleback in breeding colors
Gravid female stickleback
Although male-male conflict drives sexual selection in most species, new theory suggests that male-male cooperation is an underappreciated mechanism underlying the evolution of sexually-selected traits. I seek to understand how both cooperation and competition among unrelated males affects sexual selection and reproductive behaviors. To do this, I am conducting a series of field experiments with Suzanne Alonzo at UC Santa Cruz to understand how outside competition and spawning success influence parenting behavior and cooperation between pairs of unrelated males in the ocellated wrasse (Symphodus ocellatus).
COOPERATION IN GROUP-LIVING SPECIES
In nearly all species, social interactions are highly influential in determining an individual’s success within its environment. In humans, positive social interactions are correlated with increased job success, better health, and reduced stress; in other species, social interactions are critical determinants of disease spread, predation avoidance, and learning. In many species, individuals form groups and interact primarily with other group members; however, they also interact with members of other groups.
Most studies quantifying social interactions in group-living species investigate how individuals behave within their group, but do not consider how interactions within their group may change due to the presence of or interactions with other groups. This is problematic, as it is difficult to understand why individuals would cooperate or resolve conflict within their group without understanding the extent to which neighboring groups provide opportunities to leave the group. Similarly, it is difficult to understand the extent to which individuals pursue reproductive opportunities within the group without understanding how neighboring groups offer additional opportunities for current and future reproduction. My dissertation research explores how neighboring groups alter within-group social and reproductive dynamics in Neolamprologus pulcher, a cooperatively breeding cichlid fish native to Lake Tanganyika.