Mass migration and life cycle adaptation - a survival strategy of terrestrial earthworms in Central Amazonian inundation forests

Abstract

Horizontal mass migration of juveniles towards higher situated dryland areas due to annual flooding of inundation forests in the Rio Negro valley (5 - 6 months) is reported for Tairona riperna (Glossoscolecidae). The synchronization of cocoon production in adults which return to the inundation forest with receding flood, the short period needed for the offspring to mature and the acquisition of an annual life cycle are considered biolagical adaptations which enable inhabitation of an extreme biotope. Vertical mass migration is reported for Andiorrhinus venezuelanus tarumanis (Glossoscolecidae) in an inundation forest near the Rio Solimões vaiiey. Animals move from the waterlogged soil to the trunk/canopy area, shortly before annual flooding. Mucus secretion facilitates noctumal trunk ascents of individuais up to 19 cm in length.