REVIEW OF RECENT STUDIES ON REPRODUCTION IN TERRESTRIAL ISOPODS

The reproductive strategies of seven oniscid isopod species were studi ed: Hemilepistus reaumuri, Porcellio olivieri, Agabiformius sp., and A rmadillo albomarginatus inhabiting the arid Negev desert; Porcellio fi culneus, Schizidium tiberianum, and Armadillo officinalis inhabiting x eric habitats in the Mediterranean region; and Porcellio chuldaensis a nd Armadillo sp. (''brown'') inhabiting mesic habitats in the Mediterr anean region. Females were collected once or twice monthly, and change s in their ovaries' and oocyte dimensions were followed. These changes were associated with the onset of oogenesis and vitellogenesis, as we re changes in oocyte numbers. Likewise, marsupial egg, embryo, and man ca numbers were counted. Due to the fact that some females were kept i ndividually, the onset and course of oogenesis, extent of the marsupia l period, and onset and duration of manca release could be obtained. A ny artificial change in ambient photophase and temperature caused disr uption of the normal reproductive pattern. The number of oocytes, eggs , and mancas enabled calculating both oocyte and marsupial egg loss, a s well as reproductive allocation, parental investment, and reproducti ve potential. The species have shown wide variation in respect to thes e criteria. No positive relationship could be found between the reprod uctive patterns in these isopods and their anatomy, taxonomy, or ecolo gical conditions within their habitat. This suggests that the reproduc tive patterns in isopods must have evolved irrespective of environment al conditions.