Figure 1.

Two examples of alternative mating tactics. (a) Males of the bluegill sunfish (Lepomis macrochirus) are characterized by two life histories termed parental and cuckolder. Parentals defend nesting territories, court females, and provide sole parental care for the developing eggs and offspring. Cuckolders adopt a sneaking tactic when small and a female mimicry tactic when larger. The parental and cuckolder life histories likely represent a conditional strategy. (b) Females of the blue-tailed damselfly (Ischnura elegans) are characterized by three hertiable morphs, one of which mimics male coloration (androchrome). Breeding experiments implicate a single gene with three alleles and sex-limited hierarchical expression with three alleles in a dominance hierarchy: p (androchrome) which is dominant to q (infuscans) which in turn is dominant to r (infuscans–obsoleta). These heritable morphs thus represent alternative strategies. Note that males are phenotypically monomorphic and that there are also age-related colour changes, in addition to the genetic variation among the three adult female morphs.