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The Arctic and Antarctic are both cold deserts but show contrasting geographic and climatic features. Marked differences are notice able in the richness of insect communities at these high latitudes. In the north, a continuous terrestrial gradient links sub-Arctic and Arctic regions, while in the south, the Southern Ocean is an efficient barrier between the sub-Antarctic and the Antarctic. In spite of stressful environmental conditions, insects are present but species richness is poor. Functional diversity is subordinate to these constrained features. However, ecological and physiological adaptations are varied and generally show no taxonomic pattern. On sub-Antarctic islands, the recent increase in human activities has precipitated a dramatic increase in entomological diversity. In the Arctic, the spectacular underrepresentation of the Exopterygota cannot be explained only by biogeographic criteria. An ecophysiological interpretation is suggested and leads to an evolutionary hypothesis of entomoiogical biodiversity in polar regions. (C) Elsevier, Paris.