Terrestrial arthropods and low temperature

first_imgCold environments impose several ecological and physiological constraints upon arthropods, including reduction of metabolic rate, locomotory activity, and feeding. These result in slow growth rates and extended life cycles. Additionally, the probability of freezing is accentuated at subzero temperatures. Using data for Antarctic mites, the interplay of such constraints is examined, and the resultant ecophysiological adaptations outlined for a common oribatid mite (Alaskozetes antarcticus) of the maritime Antarctic. The synthesis suggests that its survival strategy is comprised of two components. First, the utilization of above-zero temperatures during the short austral summer to maximize growth and production, and thereby reproduce. These processes are aided by an elevation of its standard metabolic rate, commonly termed cold adaptation. Second, the tolerance of freezing temperatures by supercooling of all its postovum life stages throughout the entire year. Its supercooling potential is enhanced by the presence of glycerol and other polyols in the body fluids, the production of which is mediated by environmental temperature and desiccation at low relative humidities. Thus this species, in common perhaps with many other freezing susceptible arthropods, has ensured its survival in southern polar habitats by the evolution of a bipartite adaptational strategy.last_img

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