A reduced pollinator fauna typical of island environments may have relaxed stabilizing selection for strict herkogamy between floral morphs, resulting in the observed lack of reciprocity. Three species of native ground running spiders were compared with an introduced orb weaving species for genetic differentiation over short and long geogrpahic distances. All species showed little evidence for genetic differentiation. It is unlikely that gene flow is high in these species and it is possible that large population size reduces the effect of genetic drift on population differentiation. Studies are also examining the mating behaviour in the orb weaver Araneus diadematus to determine if multiple mating occurs.
Preliminary data suggest that if multiple mating occurs it is at a low level.
Innes, D. J. 1997 Sexual reproduction of Daphnia pulex in a temporary habitat. Oecologia 111, 53-60. Innes 1991 Geographic patterns of genetic differentiation among sexual populations of Daphnia pulex . Marine Biology 133, 213-221. Marine Biology 133, 691-699.