OVER-SUMMERING OF COCOONS OF THE EARTHWORM MICROSCOLEX DUBIUS (MEGASCOLICIDAE) IN A HOT DRY MEDITERRANEAN ENVIRONMENT

In a Mediterranean climate region of South Australia, juveniles of the geophagous peregrine earthworm Microscolex dubius mature during winte r and, in spring, adults produce cocoons and then die. Cocoons have th e capacity to survive the hot, dry summer period in a dormant conditio n during which they do not hatch, even when placed in a favourable env ironment (warm and moist conditions). In the following autumn, cocoons hatched when placed in a favourable environment and produced viable y oung earthworms. Dormant cocoons remained viable after desiccation to 40% of their hydrated weight. Desiccated cocoons rehydrated within hou rs when placed in contact with free water.