Sexual Selection and Population Divergence II. Divergence in Different Sexual Traits and Signal Modalities in Field Crickets (Teleogryllus oceanicus)
Wiley for Society for the Study of Evolution (SSE)
Reason for embargo
Sexual selection can target many different types of traits. However, the relative influence of different sexually-selected traits during evolutionary divergence is poorly understood. We used the field cricket Teleogryllus oceanicus to quantify and compare how five traits from each of three sexual signal modalities and components diverge among allopatric populations: male advertisement song, cuticular hydrocarbon (CHC) profiles and forewing morphology. Population divergence was unexpectedly consistent: we estimated the among-population (genetic) variance-covariance matrix, D, for all 15 traits, and Dmax explained nearly two-thirds of its variation. CHC and wing traits were most tightly integrated, whereas song varied more independently. We modelled the dependence of among-population trait divergence on genetic distance estimated from neutral markers to test for signatures of selection vs. neutral divergence. For all three sexual trait types, phenotypic variation among populations was largely explained by a neutral model of divergence. Our findings illustrate how phenotypic integration across different types of sexual traits might impose constraints on the evolution of mating isolation and divergence via sexual selection.
We are grateful to the following people for assistance with cricket sampling, rearing and analyses: William Bailey, Stephen Blanksby, David Forbes, Benjamin Freeman, Audrey Grant, Brian Gray, Simon Hodge, Glenda Jones, Rhedyn Ollerynshaw, John Rotenberry, Suzanne Vardy, Paris Veltsos and Marlene Zuk. The Sanger Sequencing Centre at the Edinburgh Genomics Institute assisted with genetic analysis. Funding was provided by Natural Environment Research Council grants to N.W.B. (NE/G014906/1, NE/L011255/1,NE/I027800/1), a University of California Pacific Rim Research Grant to N.W.B. (08.T.PRRP.05.0029), an Erasmus exchange grant to support M.M., a University Royal Society Fellowship and Royal Society Equipment Grant to J.H., and a BBSRC David Phillips Fellowship to A.J.W. The authors declare no conflicts of interest.
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.
Accepted manuscript online: 28 March 2017