The life history of the diving beetle, Lancetes angusticollis (Curtis) (Coleoptera: Dytiscidae), on sub-Antarctic South Georgia

Arnold, R.J.; Convey, P. ORCID: https://orcid.org/0000-0001-8497-9903. 1998 The life history of the diving beetle, Lancetes angusticollis (Curtis) (Coleoptera: Dytiscidae), on sub-Antarctic South Georgia. Polar Biology, 20 (3). 153-160. 10.1007/s003000050291

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Abstract/Summary

Two populations of the world's most southerly diving beetle (Lancetes angusticollis) were studied on sub-Antarctic South Georgia between November 1995 and April 1996. Parallel observations were made on laboratory cultures of each life stage. All juvenile stages of L. angusticollis are voracious predators, preying mainly on the herbivorous copepod Boeckella poppei. Adult beetles additionally predate benthic ostracods. Laboratory predation rates and held population densities found in this study suggest that L. angusticollis has a more significant impact on its prey than recognised in recent studies of South Georgian lakes. Spring field samples contained only a few individuals of larval instar IV and adults. Young larvae were present from December onwards, with a rapid progression through juvenile instars during the summer months. Fourth instar larvae left the water for pupation between mid-December and at least mid-February. Combining these observations with known developmental threshold temperatures for each life stage implies that L. angusticollis has a complex biennial (minimum) life-cycle, with overwintering possible in three life stages [aquatic larvae, terrestrial pupae (not proven) and aquatic adults]. L. angusticollis may be a suitable indicator species in the context of climate warming studies: a small (1 degrees C) rise in mean environmental temperatures, comparable to that already observed at several sub-Antarctic and maritime Antarctic localities, would allow completion of an annual (univoltine) life-cycle, with concomitant rapid population increase, and serious implications for trophic interactions in these simple lake ecosystems.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1007/s003000050291
Programmes:	BAS Programmes > Other
ISSN:	07224060
NORA Subject Terms:	Biology and Microbiology Zoology Ecology and Environment
Date made live:	04 Aug 2010 13:59 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/10184

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1007/s003000050291

Programmes:

BAS Programmes > Other

ISSN:

07224060

NORA Subject Terms:

Biology and Microbiology
Zoology
Ecology and Environment

Date made live:

04 Aug 2010 13:59 +0 (UTC)