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Testing a post-copulatory pre-zygotic reproductive barrier in a passerine species pair

Cramer, Emily R. A.; Laskemoen, Terje; Eroukhmanoff, Fabrice; Haas, Fredrik LU ; Hermansen, Jo S.; Lifjeld, Jan T.; Rowe, Melissah; Saetre, Glenn-Peter and Johnsen, Arild (2014) In Behavioral Ecology and Sociobiology 68(7). p.1133-1144
Abstract
Sexual selection may drive speciation, but most research focuses on pre-copulatory sexual selection, overlooking post-copulatory processes. Post-copulatory sexual selection in allopatric populations could drive divergence in post-copulatory pre-zygotic (PCPZ) phenotypes, limiting gene flow upon secondary contact. Here, we performed in vitro experiments examining one potential PCPZ barrier between two closely related passerine species, house sparrows (Passer domesticus) and Spanish sparrows (Passer hispaniolensis). In birds, crossing in the vagina may be particularly challenging for sperm, so we tested the effect of female reproductive tract fluids on sperm swimming speed and motility. If a PCPZ barrier exists at this stage of the... (More)
Sexual selection may drive speciation, but most research focuses on pre-copulatory sexual selection, overlooking post-copulatory processes. Post-copulatory sexual selection in allopatric populations could drive divergence in post-copulatory pre-zygotic (PCPZ) phenotypes, limiting gene flow upon secondary contact. Here, we performed in vitro experiments examining one potential PCPZ barrier between two closely related passerine species, house sparrows (Passer domesticus) and Spanish sparrows (Passer hispaniolensis). In birds, crossing in the vagina may be particularly challenging for sperm, so we tested the effect of female reproductive tract fluids on sperm swimming speed and motility. If a PCPZ barrier exists at this stage of the fertilization process, heterospecific female fluids are predicted to reduce sperm swimming speed or motility relative to conspecific female fluid. We found that house sparrow female fluids affected the two species' sperm asymmetrically, depending on the control sperm velocity and male species. Overall, however, sperm performed equally in conspecific and heterospecific female fluids, and the species had similar sperm morphology and sperm swimming performance. Low divergence in PCPZ phenotypes between species, perhaps because post-copulatory sexual selection is stabilizing or only moderately strong in these taxa, may be insufficient to cause an overall PCPZ barrier. Reinforcement may be unlikely to drive PCPZ barriers for this species pair, because relatively effective pre-copulatory barriers exist between the species, and because hybrids can be quite successful. Testing the role of PCPZ barriers in birds with more divergent PCPZ phenotypes will improve our understanding of speciation in passerines. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Post-copulatory sexual selection, Sperm competition, Spermmotility, Speciation
in
Behavioral Ecology and Sociobiology
volume
68
issue
7
pages
1133 - 1144
publisher
Springer
external identifiers
  • wos:000337233500008
  • scopus:84902550890
ISSN
1432-0762
DOI
10.1007/s00265-014-1724-9
language
English
LU publication?
yes
id
c648c765-9c52-4233-856a-2d66e75b93cb (old id 4539134)
date added to LUP
2014-07-16 15:32:33
date last changed
2017-11-12 03:49:35
@article{c648c765-9c52-4233-856a-2d66e75b93cb,
  abstract     = {Sexual selection may drive speciation, but most research focuses on pre-copulatory sexual selection, overlooking post-copulatory processes. Post-copulatory sexual selection in allopatric populations could drive divergence in post-copulatory pre-zygotic (PCPZ) phenotypes, limiting gene flow upon secondary contact. Here, we performed in vitro experiments examining one potential PCPZ barrier between two closely related passerine species, house sparrows (Passer domesticus) and Spanish sparrows (Passer hispaniolensis). In birds, crossing in the vagina may be particularly challenging for sperm, so we tested the effect of female reproductive tract fluids on sperm swimming speed and motility. If a PCPZ barrier exists at this stage of the fertilization process, heterospecific female fluids are predicted to reduce sperm swimming speed or motility relative to conspecific female fluid. We found that house sparrow female fluids affected the two species' sperm asymmetrically, depending on the control sperm velocity and male species. Overall, however, sperm performed equally in conspecific and heterospecific female fluids, and the species had similar sperm morphology and sperm swimming performance. Low divergence in PCPZ phenotypes between species, perhaps because post-copulatory sexual selection is stabilizing or only moderately strong in these taxa, may be insufficient to cause an overall PCPZ barrier. Reinforcement may be unlikely to drive PCPZ barriers for this species pair, because relatively effective pre-copulatory barriers exist between the species, and because hybrids can be quite successful. Testing the role of PCPZ barriers in birds with more divergent PCPZ phenotypes will improve our understanding of speciation in passerines.},
  author       = {Cramer, Emily R. A. and Laskemoen, Terje and Eroukhmanoff, Fabrice and Haas, Fredrik and Hermansen, Jo S. and Lifjeld, Jan T. and Rowe, Melissah and Saetre, Glenn-Peter and Johnsen, Arild},
  issn         = {1432-0762},
  keyword      = {Post-copulatory sexual selection,Sperm competition,Spermmotility,Speciation},
  language     = {eng},
  number       = {7},
  pages        = {1133--1144},
  publisher    = {Springer},
  series       = {Behavioral Ecology and Sociobiology},
  title        = {Testing a post-copulatory pre-zygotic reproductive barrier in a passerine species pair},
  url          = {http://dx.doi.org/10.1007/s00265-014-1724-9},
  volume       = {68},
  year         = {2014},
}