HANDICAPS NOT OBLIGATORY IN SEXUAL SELECTION FOR RESISTANCE GENES

In previous models of parasite-driven sexual selection, the signals th at reveal parasite resistances and that are used in mate choice should be costly to be reliable (''Handicap Principle''). However, sometimes parameter constellations could exist that allow for cheap signals dir ectly revealing the identity of resistance genes. Despite the general conflict of interests between the sexes, sexual selection may, in thes e cases, have led males to focus on improving their offspring's surviv al chances instead of trying to get a maximum number of offspring. Mal es may achieve this by allowing choosy females to optimize costs. and benefits of each resistance in the progeny. Multiple signals (such as odours) may serve to encode the necessary information about the identi ty of resistance genes. As an example, the connection between the majo r histocompatibility complex and odour-based mate choice in mice could be explained by this hypothesis.