Sexual selection: separating genes from imprinting

Abstract

Owens et al.1xOwens, I.P.F. et al. Trends Ecol. Evol. 1999; 214: 131–132Abstract | Full Text | Full Text PDF | Scopus (40)See all References1 have recently reviewed the importance of imprinting as a mechanism of sexual selection. They paid less attention to how the evolutionary consequences of imprinted and genetically determined aesthetic criteria may differ and interact.When offspring are reared by their genetic parents, the evolutionary consequences of both a genetic and a cultural basis for the transmission of aesthetic partner choice criteria would coincide2xCulture and the Evolutionary Process. Boyd, R. and Richerson, P.J. See all References2. This is because parental fitness is directly dependent on the criteria of partner choice passed onto the offspring whether genetically or through imprinting. There are, however, three types of situation where the evolutionary consequences of culturally and genetically determined criteria of partner choice may diverge: when offspring are reared by individuals other than by their genetic parents. This may happen through (1) extra-pair paternity caused by the promiscuous behaviour of females, which results in paternal care directed towards young fathered by other males, (2) brood parasitism and (3) cooperative breeding. In all these cases, if partner-choice is culturally determined, young may learn from their social parents aesthetic criteria different from the ones learnt by their genetic parents. Whether these differences are detrimental or beneficial to the young and its genetic and social parents may vary with socio-environmental conditions. It is thus difficult to generate predictions about the direction and magnitude of the fitness consequences of learning partner choice from tutors other than their parents. However, it is conceivable that when partner choice is imprinted, the potential discrepancy between the aesthetic criteria of genetic and social parents may affect the evolution of the reproductive strategies I have mentioned (1–3).For example, in a sperm competition scenario, the possibility that foster fathers can imprint daughters of other males with their own sexual preference might influence the tradeoff between parental care and confidence of paternity, and change our current interpretation of ‘misdirected’ paternal care3xSperm Competition and Sexual Selection. Wright, J. : 117–145See all References3. Owens et al.1xOwens, I.P.F. et al. Trends Ecol. Evol. 1999; 214: 131–132Abstract | Full Text | Full Text PDF | Scopus (40)See all References1 refer to a cross-fostering experiment in which lambs reared by goats developed a preference to copulate with female goats rather than sheep4xKendrick, K.M. et al. Nature. 1998; 395: 229–230Crossref | PubMed | Scopus (129)See all References4. It is arguable whether interspecifc parental care is frequent across the animal kingdom. In fact, where interspecific parenting does occur, little evidence suggests that behaviours are determined by foster parents5xBrooke, M., de, L., and Davies, N.B. Ethology. 1991; 89: 154–166CrossrefSee all References, 6xTeuschl, Y. et al. Anim. Behav. 1998; 56: 1425–1433Crossref | PubMed | Scopus (45)See all References. However, among intraspecific brood parasites, partner choice may be learnt. In cooperative-breeding systems, the time when young are most likely to be imprinted may influence the behaviour of helpers; for example, depending on the fitness consequences derived by helpers from sexually imprinting the helped brood with their aesthetic criteria. Therefore, the ability to condition future partner choice of not-directly related young may provide a further arena where the conflict between cuckolders and cuckolded, parasites and hosts, or helpers and helped is resolved, and a functional explanation for evolutionarily counterintuitive behaviours like adoption7xAvital, E. and Jablonka, E. Anim. Behav. 1994; 48: 1195–1199Crossref | Scopus (22)See all References7.Finally, when aesthetic criteria for partner choice are imprinted, genes may influence cultural transmission8xDugatkin, L.A. Behav. Ecol. 1988; 9: 323–327CrossrefSee all References8, determining how signals are perceived9xEndler, J.A. and Basolo, A. Trends Ecol. Evol. 1998; 13: 415–420Abstract | Full Text | Full Text PDF | PubMed | Scopus (408)See all References9 and how information is memorized10xClayton, N.S. et al. Neuropharmacology. 1998; 37: 441–453Crossref | PubMed | Scopus (57)See all References10, thereby creating potential for a complex and possibly conflicting interaction between the genomes of the young and its social parents.