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Experimental contact zones reveal causes and targets of sexual selection in hybridizing lizards

MacGregor, Hannah E A; While, Geoffrey M.; Barrett, Jade; Pérez I de Lanuza, Guillem; Carazo, Pau; Michaelides, Sozos and Uller, Tobias LU (2016) In Functional Ecology
Abstract

Divergence in sexually selected traits in allopatry should affect the degree and direction of hybridization. However, few studies have established the causes and targets of sexual selection during secondary contact. Common wall lizards (Podarcis muralis) from north-central Italy have highly exaggerated male sexual traits compared to populations in Western Europe. Using experimental populations, we show that this creates asymmetries in male dominance, spatial habitat use and reproductive success upon secondary contact. Hybridization occurred almost exclusively between males of the Italian lineage and females of the Western European lineage. We provide evidence to suggest stronger ongoing selection on male sexual traits within the... (More)

Divergence in sexually selected traits in allopatry should affect the degree and direction of hybridization. However, few studies have established the causes and targets of sexual selection during secondary contact. Common wall lizards (Podarcis muralis) from north-central Italy have highly exaggerated male sexual traits compared to populations in Western Europe. Using experimental populations, we show that this creates asymmetries in male dominance, spatial habitat use and reproductive success upon secondary contact. Hybridization occurred almost exclusively between males of the Italian lineage and females of the Western European lineage. We provide evidence to suggest stronger ongoing selection on male sexual traits within the dominant Italian lineage. However, these same characters did not predict hybridization, and hybrid matings contributed little to variance in male reproductive success. Instead, most hybrid offspring were sired by Italian males displaying phenotypes associated with lower within-lineage reproductive success. Thus, highly directional hybridization arises because some Italian males are out-competed within their own lineage but remain competitive relative to males of the other lineage. This pattern of hybridization is consistent with the direction of introgression in natural contact zones, but our data suggest that sexual selection acting through hybridization may be weak at the leading edge of natural hybrid zones.

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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Podarcis, Behaviour, Hybridization, Introgression, Male-male competition
in
Functional Ecology
publisher
Wiley-Blackwell
external identifiers
  • scopus:84991672263
  • wos:000395347300019
ISSN
0269-8463
DOI
10.1111/1365-2435.12767
language
English
LU publication?
yes
id
132d8fb4-7818-4d3f-a4da-4aa74962092b
date added to LUP
2017-02-21 11:06:55
date last changed
2017-10-22 05:27:01
@article{132d8fb4-7818-4d3f-a4da-4aa74962092b,
  abstract     = {<p>Divergence in sexually selected traits in allopatry should affect the degree and direction of hybridization. However, few studies have established the causes and targets of sexual selection during secondary contact. Common wall lizards (Podarcis muralis) from north-central Italy have highly exaggerated male sexual traits compared to populations in Western Europe. Using experimental populations, we show that this creates asymmetries in male dominance, spatial habitat use and reproductive success upon secondary contact. Hybridization occurred almost exclusively between males of the Italian lineage and females of the Western European lineage. We provide evidence to suggest stronger ongoing selection on male sexual traits within the dominant Italian lineage. However, these same characters did not predict hybridization, and hybrid matings contributed little to variance in male reproductive success. Instead, most hybrid offspring were sired by Italian males displaying phenotypes associated with lower within-lineage reproductive success. Thus, highly directional hybridization arises because some Italian males are out-competed within their own lineage but remain competitive relative to males of the other lineage. This pattern of hybridization is consistent with the direction of introgression in natural contact zones, but our data suggest that sexual selection acting through hybridization may be weak at the leading edge of natural hybrid zones.</p>},
  author       = {MacGregor, Hannah E A and While, Geoffrey M. and Barrett, Jade and Pérez I de Lanuza, Guillem and Carazo, Pau and Michaelides, Sozos and Uller, Tobias},
  issn         = {0269-8463},
  keyword      = {Podarcis,Behaviour,Hybridization,Introgression,Male-male competition},
  language     = {eng},
  month        = {10},
  publisher    = {Wiley-Blackwell},
  series       = {Functional Ecology},
  title        = {Experimental contact zones reveal causes and targets of sexual selection in hybridizing lizards},
  url          = {http://dx.doi.org/10.1111/1365-2435.12767},
  year         = {2016},
}