Does personality affect premating isolation between locally-adapted populations?

Abstract

BackgroundOne aspect of premating isolation between diverging, locally-adapted population pairs is female mate choice for resident over alien male phenotypes. Mating preferences often show considerable individual variation, and whether or not certain individuals are more likely to contribute to population interbreeding remains to be studied. In the Poecilia mexicana-species complex different ecotypes have adapted to hydrogen sulfide (H2S)-toxic springs, and females from adjacent non-sulfidic habitats prefer resident over sulfide-adapted males. We asked if consistent individual differences in behavioral tendencies (animal personality) predict the strength and direction of the mate choice component of premating isolation in this system.ResultsWe characterized focal females for their personality and found behavioral measures of ‘novel object exploration’, ‘boldness’ and ‘activity in an unknown area’ to be highly repeatable. Furthermore, the interaction term between our measures of exploration and boldness affected focal females’ strength of preference (SOP) for the resident male phenotype in dichotomous association preference tests. High exploration tendencies were coupled with stronger SOPs for resident over alien mating partners in bold, but not shy, females. Shy and/or little explorative females had an increased likelihood of preferring the non-resident phenotype and thus, are more likely to contribute to rare population hybridization. When we offered large vs. small conspecific stimulus males instead, less explorative females showed stronger preferences for large male body size. However, this effect disappeared when the size difference between the stimulus males was small.ConclusionsOur results suggest that personality affects female mate choice in a very nuanced fashion. Hence, population differences in the distribution of personality types could be facilitating or impeding reproductive isolation between diverging populations depending on the study system and the male trait(s) upon which females base their mating decisions, respectively.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0712-2) contains supplementary material, which is available to authorized users.

Extreme environments and the origins of biodiversity: Adaptation and speciation in sulphide spring fishes

“…Examples include modifications of morphological (body shape and organ size; Tobler et al., ; Tobler, Scharnweber, et al. ; Schulz‐Mirbach et al., ), physiological (tolerance and metabolic rates; Tobler et al., ; Passow, Arias‐Rodriguez, & Tobler, ), behavioural (aggression and personality; Riesch et al., ; Bierbach et al., ; Sommer‐Trembo et al., ; Bierbach, Arias Rodriguez, & Plath, ) and life history traits (fecundity and offspring size; Riesch, Plath, Garcia de Leon, & Schlupp, ; Riesch et al., ). Hence, proximate populations in different habitat types have diverged in complex phenotypes that span many different suites of traits, and a key question is how divergence in multivariate phenotypes arises.…”

“…One such mechanism could be intersexual selection, and mate choice experiments have indicated that migrants from sulphidic to nonsulphidic habitats are at a significant disadvantage, with fish from nonsulphidic habitats avoiding potential mating partners from sulphidic ones (Plath et al., ; Sommer‐Trembo et al., ). Such assortative mating has been found to be critical during ecological speciation, because it counteracts the homogenizing effects of gene flow (van Doorn, Edelaar, & Weissing, ); yet, how assortative mating patterns arise often remains unclear.…”

Personality differentially affects individual mate choice decisions in female and male Western mosquitofish (Gambusia affinis)

“…For several species, we have a fairly good understanding of why and how choosing individuals (both females and males) perceive and respond to various phenotypic traits of potential mating partners, including morphological traits [ 5 , 6 ], color ornaments [ 7 – 9 ], acoustic signals [ 10 – 12 ] and behavioral displays, i.e., ritualized courtship behaviors [ 6 , 13 , 14 ]. Recently, there has been increasing interest as to whether and how consistent individual differences in behavioral tendencies—also referred to as animal personality [ 15 ]—affect individual mate choice decisions [ 16 – 18 ]. Empirical studies in this direction mainly focused on how personality traits may influence female mate choice decisions, even though behavioral repeatability was not assessed in all cases; they either investigated the effects of male personality traits as a potential mate choice criterion [ 19 – 21 ] or how choosing females’ personality type affects their mating decisions [ 18 , 22 ].…”

Different preference functions act in unison: mate choice and risk-taking behaviour in the Atlantic molly (Poecilia mexicana)

“…We used emergence tests (Brown, Jones & Braithwaite, 2005; Sommer-Trembo & Plath, 2018) to assess individuals’ risk-taking behaviour. Poecilia mexicana (including the population studied here) has repeatedly been characterized for risk-taking behaviour, and previous studies reported high behavioural repeatability, with R-values ranging between 0.53 and 0.64 ( freezing time after a simulated predator attack , R = 0.64, Sommer-Trembo et al, 2016a; repeatability across time to emerge from shelter and freezing time after a simulated predator attack , R = 0.53, Sommer-Trembo & Plath, 2018). Slightly lower, yet significant R-values were reported for the related guppy ( time to emerge from shelter , R = 0.51, Brown & Irving, 2013; time to emerge from shelter , R = 0.51 for females and R = 0.36 for males, Irving & Brown, 2013; time to emerge from shelter , R = 0.33, White, Kells & Wilson, 2016) and other poeciliid fishes (e.g., Gambusia affinis, time to emerge from shelter , R = 0.29 in Cote, Fogarty, Weinersmith, Brodin & Sih, 2010 and R = 0.39 in Gomes-Silva, Liu, Chen, Plath & Sommer-Trembo, 2017; Poecilia vivipara, time to emerge from shelter , R = 0.70, Sommer-Trembo et al 2016b).…”