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MHC genotype predicts mate choice in the ring-necked pheasant Phasianus colchicus
M Baratti1, F Dessì-Fulgheri, R Ambrosini
1Istituto per lo Studio degli Ecosistemi, Sesto Fiorentino, via Madonna del Piano 10, Florence, Italy. baratti@ise.cnr.it
Journal of Evolutionary Biology
|May 18, 2012
Summary
Female pheasants prefer mates with intermediate genetic diversity at the major histocompatibility complex (MHC) genes. Testosterone exposure in ovo did not alter this MHC-based mate choice, suggesting MHC dissimilarity influences mating decisions to benefit offspring health.
Area of Science:
- Evolutionary biology
- Behavioral ecology
- Immunogenetics
Background:
- Major histocompatibility complex (MHC) genes influence mate choice in many vertebrate species.
- Androgen-mediated maternal effects can impact adult phenotypes, potentially interacting with MHC genotype in mating and reproductive success.
Purpose of the Study:
- To investigate how in ovo testosterone (T) exposure affects MHC-based mate choice in ring-necked pheasants.
- To determine the relationship between MHC genotype dissimilarity and female mating preferences.
Main Methods:
- Experimental in ovo testosterone administration to pheasant eggs.
- Observation and analysis of female mating preferences based on male MHC genotypes.
- Assessment of male MHC heterozygosity, diversity, ornament expression, and dominance rank.
Main Results:
- In ovo testosterone treatment did not significantly alter MHC-based mate choice.
- Females avoided mating with males possessing entirely dissimilar MHC genotypes.
- A non-significant trend indicated avoidance of MHC-identical males, suggesting a preference for intermediate MHC dissimilarity.
Conclusions:
- Female pheasants exhibit a preference for intermediate MHC dissimilarity in mates, not extreme similarity or dissimilarity.
- MHC-based mating preferences in this species are not mediated by male ornaments or dominance rank.
- These preferences may have evolved to optimize offspring MHC diversity and reduce risks of autoimmune diseases or disrupted coadapted gene pools.
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