Microsatellite Support for Active Inbreeding in a Cichlid Fish

In wild animal populations, the degree of inbreeding differs between species and within species between populations. Because mating with kin often results in inbreeding depression, observed inbreeding is usually regarded to be caused by limited outbreeding opportunities due to demographic factors like small population size or population substructuring. However, theory predicts inclusive benefits from mating with kin, and thus part of the observed variation in inbreeding might be due to active inbreeding preferences. Although some recent studies indeed report kin mating preferences, the evidence is still highly ambiguous. Here, we investigate inbreeding in a natural population of the West African cichlid fish Pelvicachromis taeniatus which showed clear kin mating preferences in standardized laboratory experiments but no inbreeding depression. The presented microsatellite analysis reveals that the natural population has, in comparison to two reference populations, a reduced allelic diversity (A = 3) resulting in a low heterozygosity (Ho = 0.167) pointing to a highly inbred population. Furthermore, we found a significant heterozygote deficit not only at population (Fis = 0.116) but also at subpopulation level (Fis = 0.081) suggesting that inbreeding is not only a by-product of population substructuring but possibly a consequence of behavioral kin preferences

Characteristics and level of aggression by female Pied Flycatchers at different distances from the nest hole

Proposed reasons for female aggression include defence of nest site or food resources on their territory, prevention of intraspecific brood parasitism or infanticide, or monopolisation of male's contribution to feeding of young. Here I investigate the characteristics and the level ofaggression of Pied Flycatcher (Ficedula hypoleuca) females at different distances from the current nest site during the nest building and egg laying period . A live female was presented in a cage 1, 10, 20 and 40 m away from the nest box of the females and the behaviour of the focal females was recorded. In total, we conducted 76 presentations (19 per distance category). The time spent by females at their own nest box increased significantly with the decreasing distance of the intruded female . This suggests that females used staying at their own nest box as a defence when an intruder was very close. Female aggressive behaviour was concentrated around the nest site and decreased gradually as the distance from the nest hole increased. The main reason for female aggression seems to be the need to defend their own nest site against intruders. However, this does not totally exclude the importance of other reasons for female aggression . Both the intensity and characteristics of female-female aggression were dependent on the distance from the current nest site . This should be taken account when different studies on the level of female aggression are compared

Inbreeding level does not induce female discrimination between sibs and unrelated males in guppies

Significant empirical evidence has demonstrated the importance of discriminative mate choice as a mechanism to avoid inbreeding. Incestuous mating can be avoided by recognition of kin. The guppy, Poecilia reticulata, is a livebearer with a polygamous mating system and active female choice. Despite potential inbreeding costs in the guppy, Viken et al. (Ethology 112:716&ndash;723, 2006) and Pitcher et al. (Genetica 134:137&ndash;146, 2008) have found that females do not discriminate between sibs and unrelated males. However, populations experiencing different inbreeding histories can have different levels of inbreeding avoidance, and it is possible that the lack of inbreeding avoidance observed in guppies is a consequence of using outbred fish only. Here we tested the preference of female guppies with different inbreeding coefficients, for olfactory cues of males that were either unrelated but had the same inbreeding coefficient, or were related (i.e. brother) with the same inbreeding coefficient. We found no evidence that female guppies preferred unrelated males with the same inbreeding coefficient. Moreover, inbreeding level did not influence female preference for unrelated males, suggesting that inbreeding history in a population has no influence on female discrimination of unrelated males in guppies. <br /