Air-breathing littoral mites of sub-Antarctic South Georgia

Nine species of littoral air-breathing Acari were collected at Husvik Harbour, South Georgia, comprising three Parasitiphis (Rhodacaridae), one Nanorchestes (Nanorchestidae), two Halo-zetes (Podacaridae) and three Hyadesia (Hyadesidae). All of the adaptive physiological and structural features observed in these mites are paralleled in related European littoral species. Although the predatory Parasitiphis spp. may cohabit in upper littoral crevices and feed on similar prey, they forage among different habitats. By contrast, Halozetes and Hyadesia spp. frequently occur together and occupy very similar niches, but competition does not appear to be significant and co-habitation may be a mutually advantageous strategy to prevent dislodgement by wave action.