A taste for the familiar: explaining the inbreeding paradox

• Published in: Trends in ecology & evolution (Amsterdam) Vol. 38; no. 2; pp. 132 - 142
• Main Authors: Dorsey, Owen C., Rosenthal, Gil G.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2023
• Subjects: Animals; assortative mating; conspecific mate preference; Inbreeding; inbreeding avoidance; mate choice; Mating Preference, Animal; Reproduction; Sexual Behavior, Animal; Taste; conspecific mate preference; assortative mating; mate choice; inbreeding avoidance
• ISSN: 0169-5347; 1872-8383
• DOI: 10.1016/j.tree.2022.09.007

The negative consequences of inbreeding have led animal biologists to assume that mate choice is generally biased against relatives. However, inbreeding avoidance is highly variable and by no means the rule across animal taxa. Even when inbreeding is costly, there are numerous examples of animals failing to avoid inbreeding or even preferring to mate with close kin. We argue that selective and mechanistic constraints interact to limit the evolution of inbreeding avoidance, notably when there is a risk of mating with heterospecifics and losing fitness through hybridization. Further, balancing inbreeding avoidance with conspecific mate preference may drive the evolution of multivariate sexual communication. Studying different social and sexual decisions within the same species can illuminate trade-offs among mate-choice mechanisms. Individuals often mate with relatives, even when it is costly: the ‘inbreeding paradox’.Avoiding kin shares neural and molecular mechanisms with other social tasks, such as affiliative behavior and conspecific mate preference.‘Active’ inbreeding avoidance battles against nonsexual kin affiliation.Trade-offs between conspecific preference and inbreeding avoidance may constrain or facilitate hybridization.