Unmasking frequency-dependent selection in tri-cultures of Drosophila melanogaster

Abstract

Larval-to-adult viability was measured for three strains of Drosophila melanogaster: a wild strain and two eye colour mutant strains (cardinal and sepia) starting from seventy different genotypic compositions. Analyses of a sub-set of the data (not considering all genotypic frequencies) demonstrate frequency-dependence in the three strains. These results suggest that in this experiment, frequency-dependent selection may be masked by other selective forces, only being apparent when specific analyses are carried out.

The capture of heritable variation for genetic quality through social competition

“…This results from the concerted coevolution of allelic effects with the social competitive environment and leads to long-term cyclical variation in allele frequencies akin to frequency dependent selection (despite the assumption of constant directional selection). There is some empirical evidence that systems the type of which we assume here exist in nature (Adell et al 1989;Sinervo and Lively 1996), however they have rarely been studied in experimental systems and their prevalence remains unknown (Hemmat and Eggleston 1989).…”

“…Whether competition is generally transitive or non-transitive is not well established. For example, there have been analyses of trigenetic interactions showing that competitive interactions can be subtle and complex (e.g., Castro et al 1985;Hemmat and Eggleston 1989) and can also contribute to negative frequency dependence amongst competing genotypes (Adell et al 1989). Thus, whether either model applies to any particular system will depend largely on the nature of competition in that system; this must be established empirically because there is no simple generalization that can be made about competition amongst genotypes.…”

The Maintenance of Heritable Variation Through Social Competition

“…However, the degree to which such interactions are prevalent in natural populations remains an empirical problem and the generality of whether competitive hierarchies evolve to be transitive or nontransitive in nature is not well known. For example, there is experimental evidence that three‐way genetic competitive interactions can be significant and complex (e.g., Castro et al 1985; Hemmat and Eggleston 1989), and may exhibit negative frequency dependence (Adell et al 1989). In contrast, there is a much larger body of literature examining competitive transitivity in interspecific interactions, which has demonstrated that such a pattern of nontransitivity may be relatively common, but it is obviously unclear the extent to which patterns from interspecific competition are mirrored at the intraspecific level.…”

Adaptive significance of amylase polymorphism in Drosophila . XII. density- and frequency-dependent selection at the Amy locus in Drosophila subobscura reared on media with different carbohydrate composition

“…Although these types of natural selection are relatively frequent, they may be difficult and sometimes impossible to detect. This may be because of their weak expression, or their effect may be ‘masked’ by other selective forces that maintain polymorphism (Hedrick et al 1976; Adel et al 1989). The existence of different forms of density‐dependent and frequency‐dependent selection has been observed in many organisms at different levels of genetic and phenotypic variability (Clarke 1975), including human populations (Hedrick and Thomson 1988), as well as mating advantage of the rare Drosophila genotype (Ehrman and Parsons 1976; Terzić et al.…”