ABSTRACT
GUNILLA ROSENQVIST Department of Zoology, Uppsala University, Box 561, S-751 22 Uppsala, Sweden
INTRODUCTION
In most animals, the rate of female reproduction limits male reproductive rate and males compete to mate with females. This sexual competition promotes traits which enhance male mating success, either by competitiveness between males or by attracting females. The resulting sexual selection is thought to explain why males are generally larger, more colourful, more vocal and more conspicuous, as well as more aggressive than females. In contrast, role reversed species are those in which females are the predominant competitors for access to mates. One consequence of role reversal is that females, rather than males, are likely to be more modified by sexual selection (Vincent et al., 1992). The pipefish, Nerophis ophidion (Figure 1), is an example of a role reversed species. Here we find competing females with elaborate secondary sexual characters and choosy males. This article examines the causes and consequences of sex role reversal in the Syngnathid fish, Nerophis ophidion.
