7 - The evolution of mating systems in the Zoraptera: mating variations and sexual conflicts

Summary

ABSTRACT

Two sympatric species of Zoraptera in central America, Zorotypus barberi Gurney and Z. gurneyi Choe, exhibit distinctively divergent mating behaviors before, during, and after copulations. The mating system of Z. barberi is essentially polygynandry in which both males and females mate with multiple mates. Males of Z. barberi perform elaborate precopulatory courtship involving courtship gifts, provide extra stimulation during copulation, and continue to court for additional copulations. Females appear to exert almost exclusive control over mating by being able to reject males at any point during the entire mating episode. In addition to deciding with whom to mate and how long each copulation lasts, Z. barberi females also control the frequency of copulations. They can mate with one male repeatedly, with different males, or both. Among the hypotheses examined, the material–benefit, postcopulatory female choice, sperm–supply, and fertilization–enhancement hypotheses, or some combinations of them, appear to provide good explanations for the observed mating variations in Z. barberi. Alternatively, repeated mating may be a result of ‘parceling’ of courtship gifts by males to guard females for a longer period of time. In Z. gurneyi, males gain considerable control over mating by establishing dominance hierarchies among themselves and thus predetermining female mating decisions to a certain degree. Zorotypus gurneyi males display no apparent precopulatory courtship; once genital coupling is made, they are able to prolong copulations by everting much of their internal genitalia into the female. After copulations, dominant Z. gurneyi males continue to protect their harems of females from other males.