Haldane's rule revisited: do hybrid females have a shorter lifespan? Survival of hybrids in a recent contact zone between two large gull species

• Published in: Journal of evolutionary biology Vol. 27; no. 6; pp. 1248 - 1255
• Main Authors: Neubauer, G, Nowicki, P, Zagalska‐Neubauer, M
• Format: Journal Article
• Language: English
• Published: Switzerland Blackwell Science 01-06-2014; Blackwell Publishing Ltd
• Subjects: adults; Animal reproduction; Animals; Birds; capture–recapture; Charadriiformes - genetics; Charadriiformes - physiology; data collection; Female; females; Haldane's rule; herring; hybrid fitness; Hybrid Vigor; Hybridization; Hybridization, Genetic; hybrids; large white‐headed gulls; Larus argentatus; Larus cachinnans; longevity; Longevity - genetics; Male; males; Sex Factors; survival rate; Larus argentatus; Haldane's rule; capture-recapture; large white-headed gulls; longevity; hybrid fitness; hybridization; Larus cachinnans
• ISSN: 1010-061X; 1420-9101
• DOI: 10.1111/jeb.12404

Haldane's rule predicts that particularly high fitness reduction should affect the heterogametic sex of interspecific hybrids. Despite the fact that hybridization is widespread in birds, survival of hybrid individuals is rarely addressed in studies of avian hybrid zones, possibly because of methodological constraints. Here, having applied capture–mark–recapture models to an extensive, 19‐year‐long data set on individually marked birds, we estimate annual survival rates of hybrid individuals in the hybrid zone between herring (Larus argentatus) and Caspian (Larus cachinnans) gulls. In both parental species, males have a slightly higher survival rate than females (model‐weighted mean ± SE: herring gull males 0.88 ± 0.01, females 0.87 ± 0.01, Caspian gull males 0.88 ± 0.01, females 0.87 ± 0.01). Hybrid males do not survive for a shorter time than nonhybrid ones (0.88 ± 0.01), whereas hybrid females have the lowest survival rate among all groups of individuals (0.83 ± 0.03). This translates to a shorter adult (reproductive) lifespan (on average by 1.7–1.8 years, i.e. ca 25%) compared with nonhybrid females. We conclude that, in line with Haldane's rule, the lower survival rate of female hybrids may contribute to selection against hybrids in this hybrid zone.