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Science et changements planétaires / Sécheresse

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Des insectes résistants à la sécheresse Volume 1, issue 4, Décembre 1990

Author
Université de Provence. Laboratoire de Biosystématique et Écologie méditerranéenne, UA 1152, Centre de Saint-Jérôme, Case 421 bis, avenue Escadrille Normandie-Niémen, 13397 Marseille Cedex 13, France.
  • Page(s) : 265-71
  • Published in: 1990

Facing hydric stress in the soil of areas with more or less long periods of drought (mediterranean, arid and semi-aria regions) terrestrial arthropods have developped different adaptive strategies. Microarthropods are definitely unable to survive in areas where hydric deficit is too severe. Since the appearance of a dryer climate, they have migrated down deep layers of the soil (caves, caverns) or are presently sheltering in refuges with favourable hydric conditions, habitats they leave only from time to time (at night or early in the morning). Microarthropods can live at both adult and active stages, in areas where they can withstand dryness (about pF 4,2) thanks to morphological, anatomic, or ecophysiological adaptations such as a thick cuticule, temporary starvation or regulation of hydric transfert during transpiration. Beyond a threshold of hydric deficit, microarthropods are only able to resist dryness in the egg stage. Some microarthropods can withstand hydric stress as inactive adults (collembola in anhydrobiosis or ecomorphosis) in the same areas where they live when water availability is adequate. They tolerate large water losses, by using special adaptative mechanisms.