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Diapause : a potent force in the evolution of freshwater crustaceans.

Fryer, Geoffrey (1996) Diapause : a potent force in the evolution of freshwater crustaceans. Hydrobiologia, 320 (1-3). pp. 1-14. ISSN 0018-8158

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Abstract

After a brief historical review of the discovery of diapause in freshwater crustaceans, its dramatic nature in certain cyclopoid copepods, in which diapausing individuals may occur at densities of > 106 per m2, is used to illustrate the enormous ecological significance of the phenomenon. Some of the problems presented by dispause in cyclopoid copepods are noted, including the different behaviour in different lakes of what appears to be a single species. Different physiological cues or different genetic endowments are clearly involved. The wider incidence of diapause in freshwater copepods and ostracods is noted. Among freshwater crustaceans it it the Branchiopoda that have universally adopted diapause, always at the egg stage. Even such an ancient order as the Anostraca, perhaps the most primitive of all crustaceans, produces elaborately constructed resting eggs that are capable of cryptobiosis, can remain viable in a dry state for long periods, and can tolerate extreme conditions. The nature of branchiopod resting eggs is briefly reviewed. Of these, only those of the Anomopoda are protected by containers derived from the parental carapace. These are mechanically complex in the most advanced species but, as shown by fossils, are extremely ancient structures. Factors initiating the onset and termination of diapause in branchiopods are briefly noted, and the process of hatching of resting eggs is outlined.

Item Type: Article
Journal or Publication Title: Hydrobiologia
Uncontrolled Keywords: diapause - freshwater Crustacea - antiquity - diversity - evolution
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 22034
Deposited By: ep_ss_importer
Deposited On: 17 Feb 2009 16:29
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 15:55
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/22034

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