Sexual selection of high-quality mates can conflict with species recognition if traits that govern intraspecific mate preferences also influence interspecific recognition. This conflict might be resolved by developmental plasticity and learned mate preferences, which could drive preference divergence in populations that differ in local species composition. We integrate field and laboratory experiments on two calopterygid damselfly species with population genetic data to investigate how sex differences in developmental plasticity affect population divergence in the face of gene flow. Whereas male species recognition is fixed at emergence, females instead learn to recognize heterospecifics. Females are therefore more plastic in their mate preferences than males. We suggest that this results from sex differences in the balance between sexual selection for high-quality mates and selection for species recognition. As a result of these sex differences, females develop more pronounced population divergence in their mate preferences compared with males. Local ecological community context and presence of heterospecifics in combination with sex differences in plasticity and canalization therefore shape population divergence in mate preferences. As ongoing environmental change and habitat fragmentation bring formerly allopatric species into secondary contact, developmental plasticity of mate preferences in either or both sexes might facilitate coexistence and prevent local species extinction.
Microsatellite data to estimate molecular population divergence in Calopteryx splendens (Figure 2)
Microsatellite data for “Sex differences in developmental plasticity and canalization shape population divergence in mate preferences”. BayesAss results (presented in Figure 2 in Svensson et al. (2014), as well as FST-analyses, Structure analyses and Microchecker analyses are based on these microsatellite data. The file contains genetic data from 133 individuals from seven study populations and one outgroup consisting of 90 individuals inhabiting populations along the River Loire, France. The genotypes of all damselflies were assayed at 13 microsatellite loci previously isolated for this species (see e.g. J. D. Austin et al., 2011, Mol. Ecol. Resour. 11, 757). Information on population ecology (sympatry or allopatry) is presented in Supporting Table 1 in the Supporting Material (Svensson et al. 2014).
DataFig2MicrosattelitMolecularPopulationDivergence.txt
Population divergence in female mate preferences of Calopteryx splendens (Figure 3A)
Data for C. splendens female population divergence in mate preferences in sympatric (S) and allopatric (A) populations, as shown in Fig. 3A (Svensson et al. 2014). Female mate preferences have been normalized by dividing by the average female response to conspecific C. splendens males (indicated by line at ‘1’ in Fig. 3A). For statistical tests, see legend to Fig. 3A in Svensson et al. (2014).
DataFig3AFemalePopDivergenceMatePreferences.txt
Population divergence in male mate preferences of Calopteryx splendens (Figure 3B)
Data for C. splendens male population divergence in mate preferences in sympatric (S) and allopatric (A) populations, as shown in Fig. 3B (Svensson et al. 2014). Male mate preferences have been normalized by dividing by the average male response to conspecific C. splendens females (indicated by line at ‘1’ in Fig. 3B). For statistical tests, see legend to Fig. 3B in Svensson et al. (2014).
DataFig3BMalePopDivergenceMatePreferences.txt
Sex differences in mate responses towards con- and heterospecifics in relation to population ecology (Figure 3C)
Raw data (C. splendens males and females in different populations) for mixed-model analysis testing for sex differences in mate preference responses in allopatric vs. sympatric environments (Fig. 3C and Table S2 in Svensson et al. 2014). R-code for the analysis (nlme-package) is provided in a separate Dryad data-file. We used the normalized mate preferences (rightmost column) as the response variable in the analysis and “Population identity” (here “Pop”) was a random factor.
DataFig3CIndividualMateResponses.txt
R-code for mixed-model analysis of sex differences in mate responses (Figure 3C)
R-code using the nlme-package for the statistical test of sex differences illustrated in Figure 3C (Svensson et al. 2014). To compare male and female mate preferences in relation to local ecology we performed a mixed model with “Sex” (males and females) and “Population Ecology” (allopatry vs. sympatry) and their interaction (“Sex × Population Ecology”) as independent fixed factors, and “Population identity” as a random factor (nested within the fixed factor “Population Ecology”)(Table S2). By including “Population identity” as a random factor, we adjusted for the fact all our populations contributed with multiple individuals to the analysis and hence our data points (individual mate responses) are not entirely statistically independent.
DataFig3CRCodeForMixedModelAnalysisUsingNLME.txt
Within-individual mate responses of sexually naive Calopteryx splendens males in relation to con- and heterospecific females (Figure 4A)
Raw data (male mate responses) of Fig. 4B in Svensson et al. (2014). Data are within-male mate responses of sexually naïve C. splendens males from Klingavälsåns Naturreservat in 2012 and 2013, in relation to female species presented (conspecific C. splendens females or heterospecific C. virgo females). The columns represent male mate responses in relation to conspecifics (first column) and heterospecifics (second column) in relation male ID (third column). A paired t-test shows that these sexually naïve C. splendens males show significantly stronger response towards conspecific females, unlike the situation for female mate responses (Fig. 4B). See legend to Fig. 4A in Svensson et al. (2014) for test-statistics.
DataFig4ANaiveWithinMaleResponsesPairwiseComparison.txt
Mate responses of sexually naive Calopteryx splendens females in relation to con- and heterospecific males (Figure 4B)
Raw data (female mate responses) of Fig. 4B in Svensson et al. (2014). Data are mate responses of sexually naïve C. splendens females from two populations (Klingavälsåns Naturreservat or Höje Å), in relation to male species presented (conspecific C. splendens males or heterospecific C. virgo males). There is a significant effect of female origin (population), but no effect of male species among these sexually naïve females (see legend to Fig. 4B in Svensson et al. 2014 for test-statistics).
DataFig4BNaiveFemaleResponsesKlingaAndHoje.txt
Mate responses of sexually naive Calopteryx splendens males and females in relation to heterospecific mates (Figure 4C)
Raw data (sexually naïve male and female mate responses towards heterospecifics) of Fig. 4C in Svensson et al. (2014). Mate responses have been normalized by dividing by the average response towards conspecifics mates within each sex. Data are from Klingavälsåns Naturreservat only. For statistical test of the sex difference in mate responses, see legend to Fig. 4C in Svensson et al. (2014).
DataFig4CBothSexesResponseHeterospecifics.txt