Ecological correlates of sex

Paul J. Greenwood & Jonathan Adams

The origins and maintenance of sex are still a matter of debate. Some insights may be gained by comparing the patterns of sexuality and asexuality in the Plant and Animal Kingdoms. Asexuality is probably commoner among plants than animals. Most parthenogenetic strains are almost certainly derived from sexual forebears. They occur relatively infrequently and tend not to replace their sexual ancestors throughout their range. This suggests, firstly, that such species are subject to a high rate of extincton and, secondly, that when they do arise they are comparatively unsuccessful in competition with sexual forms.

Unpredictable and complex environments should favour sex while simple communities with greater predictability and fewer predators or pathogens should have a higher frequency of asexual species. This appears to be the case. Biologically complex habitats such as tropical rain forests with a myriad of interspecific interactions have relatively few asexual species. Simpler or impoverished habitats, such as those at high altitudes and high latitudes, tend to have relatively more.

Fonte: Greenwood, P. J. & Adams, J. 1987. The ecology of sex. Londres, Arnold.