The biology of Bothrometopus elongatus (Coleoptera, Curculionidae) in a mid-altitude fellfield on sub-Antarctic Marion Island

Bothrometopus elongatus is one of four Ectemnorhinus-group species restricted to the epilithic biotope on the Prince Edward Islands. Here we examine the biology of this species over a full year at Kerguelen Rise, a mid-altitude fellfield site on Marion Island. B. elongatus adults eclose from April o...

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Bibliographic Details
Published in:Polar biology 2000-04, Vol.23 (5), p.346-351
Main Authors: BARENDSE, J, CHOWN, S. L
Format: Article
Language:English
Subjects:
Altitude
Biological and medical sciences
Climate change
Coleoptera
Curculionidae
Entomology
Environmental effects
Fundamental and applied biological sciences. Psychology
Hatching
Indigenous species
Insecta
Insects
Introduced species
Invertebrates
Islands
Larvae
Life cycle. Embryology. Development
Life history
Marine biology
Physiology. Development
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Summary:Bothrometopus elongatus is one of four Ectemnorhinus-group species restricted to the epilithic biotope on the Prince Edward Islands. Here we examine the biology of this species over a full year at Kerguelen Rise, a mid-altitude fellfield site on Marion Island. B. elongatus adults eclose from April onwards, reaching maximum densities (ca. 17 individuals m^sup -2^) in September. Females mature approximately three eggs at a time and these commence hatching in July. Larval eclosion reaches a peak in November, during which time larval densities are also highest (ca. 153 individuals m^sup -2^). The larvae develop through six instars, which is within the range found for other Ectemnorhinus-group species. The high densities of B. elongatus in fellfield habitats, and its single, virtually discrete annual generation, make this species unusual among insects indigenous to the sub-Antarctic. The latter generally have low densities compared to other micro-arthropods, prolonged life-cycles, and flexible life-histories. We suggest that the diversity of life-histories found amongst the indigenous insects at Marion Island presents considerable potential for testing environmental effects on insect life-histories. An overview of sub-Antarctic insect life-history data suggests that the indigenous species, with generally prolonged life-cycles, are at a disadvantage relative to introduced species that have more rapid cycles and often complete several generations per year. This is reason for concern given rapid climate change at these islands.[PUBLICATION ABSTRACT]
ISSN:0722-4060
1432-2056
DOI:10.1007/s003000050454