An Indirect Cue of Predation Risk Counteracts Female Preference for Conspecifics in a Naturally Hybridizing Fish Xiphophorus birchmanni

Abstract

Mate choice is context dependent, but the importance of current context to interspecific mating and hybridization is largely unexplored. An important influence on mate choice is predation risk. We investigated how variation in an indirect cue of predation risk, distance to shelter, influences mate choice in the swordtail Xiphophorus birchmanni, a species which sometimes hybridizes with X. malinche in the wild. We conducted mate choice experiments to determine whether females attend to the distance to shelter and whether this cue of predation risk can counteract female preference for conspecifics. Females were sensitive to shelter distance independent of male presence. When conspecific and heterospecific X. malinche males were in equally risky habitats (i.e., equally distant from shelter), females associated primarily with conspecifics, suggesting an innate preference for conspecifics. However, when heterospecific males were in less risky habitat (i.e., closer to shelter) than conspecific males, females no longer exhibited a preference, suggesting that females calibrate their mate choices in response to predation risk. Our findings illustrate the potential for hybridization to arise, not necessarily through reproductive “mistakes”, but as one of many potential outcomes of a context-dependent mate choice strategy.

Only distance matters – non-choosy females in a poison frog population

“…Consistent with predictions of theoretical models, empirical studies have revealed that the female mate sampling tactic is influenced by the costs of searching [21,27-31] as well as the variation in quality among potential males [32-35]. Females should become choosier with an increase in benefits and a decrease in costs [36,37].…”

Predator experience overrides learned aversion to heterospecifics in stickleback species pairs

“…One study has tested for predator effects on mate preference in sympatric males and found that male sailfin mollies (Poecilia latipinna) were less discriminating against heterospecific Amazon mollies (Poecilia formosa) in the presence of a predator than in the absence of a predator [30]. Another study found that distance from a shelter (which may be indirectly related to predation risk) increased the likelihood that swordtail females (Xiphophorus birchmanni) would mate with heterospecifics [31]. This dearth of studies on female preference is surprising given that female conspecific mate preference is the main barrier to hybridization in many species [32] and females generally invest more in each mating than males [33].…”

Female mate choice plasticity is affected by the interaction between male density and female age in a field cricket

“…As a result, females may adjust their choosiness based on their ability to afford perceived search costs. Many studies have manipulated the costs of choosiness and have found that females adjust choosiness in response to changes in a variety of factors such as parasitism (Beckers & Wagner, 2013), age (Richard, Lecomte, De Fraipont, & Clobert, 2005;Ronald, Fern andez-Juricic, & Lucas, 2012), body condition and diet (Hebets, Wesson, & Shamble, 2008;Moskalik & Uetz, 2011;Vitousek, 2009), predation (Karino, Kuwamura, Nakashima, & Sakai, 2000;Willis, Rosenthal, & Ryan, 2012), male density and trait variability (Fowler-Finn & Rodríguez, 2012a;Lehmann, 2007), and previous experiences with certain male phenotypes (FowlerFinn & Rodríguez, 2012b;Hebets, 2003;Wagner, Smeds, & Wiegmann, 2001). …”