To sink or float: the fate of dormant offspring is determined by maternal behaviour in Daphnia
Article first published online: 27 DEC 2007
Volume 53, Issue 3, pages 569–576, March 2008
How to Cite
ŚLUSARCZYK, M. and PIETRZAK, B. (2008), To sink or float: the fate of dormant offspring is determined by maternal behaviour in Daphnia. Freshwater Biology, 53: 569–576. doi: 10.1111/j.1365-2427.2007.01937.x
- Issue published online: 27 DEC 2007
- Article first published online: 27 DEC 2007
- (Manuscript accepted 6 November 2007)
- 1As the ephippia (chitinous shells enclosing diapausing eggs) of pelagic crustaceans of the genus Daphnia have been occasionally reported to float at the water surface, we considered that this might be an adaptation promoting their passive dispersal. We investigated the mechanisms by which ephippia appear at the water surface.
- 2While field surveys revealed that floating Daphnia ephippia are often numerous in various freshwater habitats, laboratory tests showed that newly formed ephippia are not buoyant initially. Once transferred to the surface by whatever means, however, they may remain there due either to surface tension or gas absorption.
- 3Video recordings showed that all ephippia at the water surface in laboratory vessels were shed there by ephippial females when moulting (despite the attendant risk of exposure to UV radiation). This implies that the moulting behaviour of female Daphnia may determine the fate of their dormant offspring, predetermining whether they remain in the natal environment (when the ephippium is released into the water column) or disperse (when it is deposited at the water surface).
- 4Our findings reveal a potential mechanism underlying the high dispersal capacity of freshwater cladocerans inhabiting island-like aquatic habitats.