Allochronic isolation can be a strong mechanism for reproductive isolation and speciation. However, imperfect allochrony and the expression of phenological plasticity can erode temporal barriers to gene flow and result in hybridization between divergent lineages. Here, we combine behavioural ecology and genomics to investigate this scenario in two closely related species of grigs in the genus Cyphoderris. These species exhibit a unique mating system whereby females feed on the fleshy hind wings of the male during copulation, and copulation with conspecific males is more likely in food-restricted females than in well-fed females. In western Canada, Cyphoderris buckelli and Cyphoderris monstrosa are sympatric but largely allochronically separated, with C. buckelli breeding earlier. However, their breeding seasons can overlap, leading to potential for older C. buckelli females to mate with young C. monstrosa males to obtain resources via sexual cannibalism. We used behavioural assays to test whether female feeding status affects the propensity for interspecific mating between C. buckelli females and C. monstrosa males. We then tested for hybridization and gene exchange in wild populations of both species, using morphology, mitochondrial DNA and genome-wide nuclear markers. We found that interspecific courtship and mating can occur, but the relationship between food restriction and increased propensity for hybridization was not significant. Although we observed intraspecific population genetic structure in both species, we found no signatures of hybridization in the morphological or genetic datasets, which suggests that postmating reproductive barriers might be preventing successful hybridization in the wild.
|Number of pages||15|
|Journal||Biological Journal of the Linnean Society|
|State||Published - Aug 28 2020|
Bibliographical noteFunding Information:
J.R.D. and K.A.J. contributed equally to this work. Genotyping by sequencing libraries were prepared at Institut de Biologie Intégrative et des Systèmes at Université Laval and sequenced at McGill University’s Génome Québec Innovation Centre. Sanger sequencing was conducted at the Molecular Biology Service Unit at the University of Alberta. We thank Terrence Chang for assistance in specimen collection, Taylor Becker for assistance with wet laboratory procedures, and Bill Cade, Paul De Luca, Andrew Mason and Glenn Morris for helpful discussions. Thank you to Thor Veen and two anonymous reviewers for helpful comments on the manuscript. This research was supported by Natural Sciences and Engineering Research Council of Canada Discovery Grants to F.A.H.S. (RGPIN 217174) and K.A.J. (RGPIN-2017-04674), a University of Lethbridge Postdoctoral Fellowship to K.A.J. and a MacEwan University Faculty of Arts and Science Research Fund to K.A.J. Figures were created using R v.3.1.1 (R Core Team, 2018) and inkscaPe v.0.91 (The Inkscape Team, 2017). Raw GBS sequencing reads are deposited in NCBI, BioProject PRJNA601897, SRA accessions SRR10907472–SRR10907567 and mtDNA GenBank accessions MT196142–MT196220. Input files for genetic datasets and raw morphological data are provided in the Supporting Information (Files S1– S3 and Table S3, respectively).
© 2020 The Linnean Society of London, Biological Journal of the Linnean Society.
- genotyping by sequencing
- population genetics
- sexual selection
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics