Testing female preferences under more natural conditions: a case study on a fiddler crab

Abstract

Mate choice is often affected by multiple factors, and there are often trade-offs associated with choosing a mate. Additionally, experiments that test for mate preferences usually rely on simple two-choice tests. These tests are, however, often less complex than the scenarios that individuals face in natural populations. Here, we test female choice in the fiddler crab Uca mjoebergi. We looked at female preference for wave rates and proximity to males in simple two-choice tests. We then mimicked a more natural choice scenario, where females faced a cluster of six courting males that differed in their distance from the female as well as in their wave rate. In addition, we tested whether female preferences under these more complex conditions were affected by the risk of predation. We found a preference for faster wave rates and closer males in twochoice tests. The preference for closer males was, however, only evident when the difference in distance was large (15 cm), not when it was small (3 cm). When females chose between six males, they preferred the males that waved faster, even if they were further away. We did not, however, find any difference in female choice when a simulated predator was present or absent. By examining a more realistic set of options that females face, we can paint a better picture of how females' trade-off costs and benefits during mate choice. Significance statementMate choice experiments often rely on two-choice tests. Mate choice, however, is often more complex under totally natural conditions. Using a two-choice experiment, we show that female fiddler crabs U. mjoebergi show a preference for faster wave rates and closer males. Under a more natural choice scenario, when choosing between six males, females preferred to travel longer to reach faster waving males. We found that female responses did not differ when a predator was present or absent. Designing choice experiments to more accurately mimic natural conditions will allow assessing trade-offs that occur in mate choice.

Predation risk regulates prey assortative mating by reducing the expected reproductive value of mates

“…Predation risk is typically assumed to affect reproductive decisions by exacerbating the immediate costs of reproductive behaviors (Zuk & Kolluru, 1998 ), and reducing prey density (Belovsky et al, 2011 ). This may limit information transfer between mates and force prey to compromise on available mates rather than searching for higher quality mates (Johnson & Basolo, 2003 ; but see Vega‐Trejo & Backwell, 2017 ). We hypothesized that, if this effect of predation dominates prey reproductive considerations, then SAM should be disrupted or at least weaken (i.e., shallower SAM slope).…”

Mate Preference Plasticity in a Critically Endangered Frog: Implications for Conservation Breeding

“…Each call frequency was represented on both sides of the hexagonal arena (see Figure 1) to reduce any potential side bias. Of note, similar approaches have been used in other mate choice studies (see Holveck et al, 2011;Vega-Trejo and Backwell, 2017).…”

Thermal and desiccation constraints drive territory preference in fiddler crabs

“…The female remains in the burrow for the~20 d incubation period until she re-emerges to release larvae (Reaney and Backwell, 2007) but the male emerges after oviposition to resume feeding, courting and mating. Female mate choice is based on multiple male traits (Holman et al, 2014;Mowles et al, 2017;Vega-Trejo and Backwell, 2017) as well as on the quality of the male's burrow (Reaney and Backwell, 2007). Females must select a burrow that prevents desiccation and tidal inundation, and that will remain structurally stable over the incubation period.…”