ORIGINAL PAPER Kendi F. Davies · Penelope Greenslade Brett A. Melbourne The invertebrates of sub-Antarctic Bishop Island Received: 3 July 1996 / Accepted: 2 October 1996 Abstract We report on the first comprehensive collec- tion of invertebrates made on sub-Antarctic Bishop Island, which lies 33 km south of Macquarie Island. A total of 15 species were collected, of which 14 also occur amongst the 168 species recorded from Macquarie Is- land. We hypothesise that the greater species richness of Macquarie Island relative to Bishop Island is largely caused by the greater habitat diversity on Macquarie Island but that other factors, including accidentally introduced species, may also be important. Introduction Bishop Island (55°06′S, 158°43′30′′E) lies 33 km south of Macquarie Island on the Macquarie Ridge, about 1,330 km southeast of Tasmania, Australia and 1,410 km north of the Antarctic continent (Lugg et al. 1978). Bishop Island is a rocky platform of about 45 m altitude and 3 ha area. It has an intermittent covering of soil of up to 15-cm depth, which is vegetated in places by the coastal cushion plant Colobanthus muscoides. The island is surrounded by 24 smaller rock stacks, which together with Bishop Island compose the Bishop and Clerk Is- lands (MacKenzie 1968). Landings on the island have been rare because of bad weather and submerged reefs. The only invertebrate species previously recorded from the island were collected during a half-hour visit by two researchers flown by helicopter from the vessel Thala Dan (Lugg et al. 1978). Before that, the only re- corded visit to Bishop Island was when a helicopter from USS Glacier landed for a few minutes on an outlying rock platform. No collections were made on that visit. Here we report on a collection made on a 3-h helicopter visit in December 1993 from the MV Icebird, and compare the Bishop Island fauna with that of Macquarie Island. Materials and methods Four invertebrate habitats were recognised on Bishop island: (1) underneath loose rocks or in rock crevices, in unvegetated areas; (2) associated with the coastal cushion plant Colobanthus muscoides; (3) in soil without vegetation; and (4) in soil, litter and amongst the rocks of bird nesting sites. Two sampling methods were used. First, hand collections were made in all habitat types using featherweight forceps and an as- pirator. Second, three samples each were collected of vegetation, soil (15-cm diameter, 10-cm depth) and material from nest bur- rows and penguin colonies. On the following day, invertebrates were extracted from these samples using Tullgren funnels (Tullg- ren 1918). Specimens were identified by taxonomic specialists. All specimens were lodged with the Australian National Insect Col- lection, CSIRO Division of Entomology, Canberra. Results Fifteen species were collected from the four terrestrial habitat types (Tables 1 and 2). All species have sub- Antarctic affinities with two species also known from the Auckland Islands, one species from New Zealand, and another from Chile ´ (Table 1). All species except Cryptopygus antarcticus maximus (Collembola) have also been recorded from neighbouring Macquarie Is- land (Table 3). Three species collected from Bishop Island are of uncertain status. The first species, a mesostigmatid mite with undescribed genus and species, was referred to by Watson (1967) as ‘‘species 2, Celaenogamasus ?’’. It is Polar Biol (1997) 17: 455–458  Springer-Verlag 1997 K.F. Davies (&) 1 · P. Greenslade · B.A. Melbourne 1 CSIRO Division of Entomology, GPO Box 1700, Canberra, ACT, 2601, Australia Present address: 1 Division of Botany and Zoology, The Australian National University, Canberra, ACT, 0200, Australia Fax: +616 249 5573; e-mail: Kendi.Davies@anu.edu.au