Female choice and social decision-making in a marine toadfish (Porichthys notatus)

Abstract

In many species, there is a fitness advantage when certain males pursue alternative fertilization strategies, leading to the evolution of male alternate reproductive tactics (ARTs). Two commonly observed male ARTs are guarders and sneakers. Guarders often compete for females, defend territories, and/or provide parental care, while sneakers are obligate cuckolders. Much of the empirical research on the evolution of male ARTs focusses on male-male competition, while often ignoring female choice. Despite garnering less attention, theory predicts that female choice could have far-reaching implications on the origin and maintenance of male ARTs. My master's research aimed to examine the influence of female choice and preferences in a species with male ARTS, the plainfin midshipman (Porichthys notatus). In Chapter 2, I investigated whether female plainfin midshipman mate choice is influenced by other females' mating decisions, referred to as mate choice copying. I describe three experiments conducted to test whether females mate choice copy. I show that females do copy after observing another female spawning; however, the mere presence of another female or previously spawned eggs in a nest were not sufficient cues to elicit copying. In Chapter 3, I investigated if female preferences for particular guarder male or nest characteristics are shared by sneaker males, since sneaker males can potentially increase their reproductive success by affiliating with female-preferred mating locations. I found no clear sneaker preferences for nests containing guarder males, larger guarder males, or eggs; however, behavioural measures indicated that the sneakers may not have engaged with the assay as intended. My research provides the first evidence of mate choice copying in plainfin midshipman and provides the groundwork for future research on social decision-making in this species. It also highlights the importance of considering female choice, along with male-male competition, when investigating male ARTs.