REPRODUCTIVE AND MOLTING CYCLES IN CAVE CRAYFISH

¹ Department of Biology, Yale University, New Haven, Connecticut 06520

1. Annual periods of reproduction and molting of Orconectes pellucidus inermis in Shiloh Cave, Indiana, have been observed. Both sexes of O. p. inermis in Shiloh Cave appear to initiate a new annual period of gametogenesis in early summer. The number of adult females whose ovary contains large, yolky oocytes is declining to an annual minimum and the majority of adult males are in form II. Eggs are being laid and hatched and young crayfish are leaving the adult and entering the stream population. Oocyte formation and growth, spermatogenesis, and maturation of spermatozoa continue during the fall months. Many adult and some large juvenile males molt to form I. During fall months most adult males are form I, they have large supplies of spermatozoa, and mating presumably occurs. Oocytes of some females begin to mature and there is an increase in the proportion of females having the ovary filled with large, yolky oocytes.

During late winter and early spring months spermatogenesis and oogenesis decline to an annual minimum, that is reached during the spring months. Concurrently many adult males molt to form II. Not all the adult females molt at this time of year. The proportion of females with large, yolky oocytes in their ovaries increases to the maximum during the spring.

2. Evidence for environmental synchronization of the reproductive and molting cycles of individuals in the population is discussed.

3. Occurrence and absence of seasonal periods of reproduction reported by other investigators in a few species of cavernicolous animals are discussed.

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				T. L. Poulson, T. L. Poulson, and W. B. White The Cave Environment Science, September 5, 1969; 165(3897): 971 - 981. [PDF]