Post-parturial reproduction in terrestrial isopods: a partial review

Abstract

This review deals with some aspects of terrestrial isopod reproduction including breeding season, breeding periods, patterns and strategies, parturition, number and size of broods and mancae. Reproductive period is described by the exact dates (i.e. season) marsupial females were collected in the field, and the duration of the breeding period. The information for both aspects was generally obtained through field work by observing marsupial females. Two reproductive patterns are used by terrestrial isopods, either a discrete (i.e. seasonal) or a continuous (i.e. non-seasonal) pattern. The discrete pattern can be either annual when females breed once a year, or they can breed biannually or multi-annually (two or more times during the year). This conclusion is based generally on observing marsupial females in the field. Therefore, this information does not apply to the reproductive pattern of the individual female since a female may use either or both patterns, i.e. seasonal and continuous. Only by raising individual females singly (with a male) can this point be clarified. This way, the breeding strategy of the same individual female can be studied. The subject is discussed and reviewed based on my research data.

Keywords:

• Isopoda
• Oniscidea
• reproductive season
• reproductive period
• reproductive strategy
• brood
• manca

Acknowledgements

Foremost the author thanks Prof. G.E. Hutchinson for enabling his choice of PhD Thesis: the study on ecophysiology of isopods. Over many years of his studies on isopods, he has received support from several colleagues: He is grateful to Profs Eduard Linsenmair, Cliff Crawford and Elisabeth Hornung for their contributions to lively discussion on isopods and to isopod research. He is grateful to Prof. Cloudsley-Thompson for providing a home for several publications and for organizing the first isopod symposium. The major contributions by his former students Drs Klara Bercovitz, Nili Cohen and Dorit Weinstein who took part in the studies on isopod reproduction are gratefully acknowledged. Yael Strolowitz, Yael Calahorra and Meirav Feibish made each major contribution to our understanding of reproduction in some isopod species. Finally, he is indebted to Drs Sachiko Suzuki and Masa Milatović for their valuable remarks on subject matters.