Seeing-good-gene-based mate choice: From genes to behavioural preferences

Area of Science:

• Evolutionary biology
• Conservation genetics
• Animal behavior

Background:

• Mate choice is crucial for reproductive success in many species.
• Understanding mate choice mechanisms in endangered species is vital for effective conservation.
• The role of the Major Histocompatibility Complex (MHC) in mate selection is increasingly recognized.

Purpose of the Study:

• To investigate MHC-based mate preference in the endangered crested ibis (Nipponia nippon).
• To quantify the impact of mate choice on reproductive output in this species.
• To determine if external traits signal underlying MHC genetic diversity.

Main Methods:

• Assessed MHC genotypes of breeding pairs.
• Analyzed nuptial plumage characteristics (color reflectance, UV) and body morphology.
• Quantified reproductive output (clutch size, egg viability, fledgling numbers).
• Compared reproductive success between naturally paired and artificially matched captive pairs.

Main Results:

• Females preferred MHC-heterozygous males with darker plumage (lower UV reflectance).
• Males preferred females lacking the DAB*d allele, who had higher body mass.
• MHC-preferred pairings resulted in higher egg weight, more fertilized eggs, and more fledglings.
• Naturally paired birds showed superior reproductive output compared to pedigree-matched captive pairs.

Conclusions:

• Mate choice, influenced by MHC genes and signaled by external traits, enhances reproductive success in crested ibises.
• Conservation programs should consider natural mate choice dynamics, potentially favoring free-mating systems over strict pedigree matching.
• Integrating genetic mate choice into conservation strategies can improve the recovery of threatened species.