EYESTALK REGULATION OF MOLT AND VITELLOGENESIS IN UCA PUGILATOR

¹ Department of Biological Sciences, Goucher College, Towson, Maryland 21204

1. The condition of the ovaries of intact and eyestalkless Uca pugilator from Florida was examined throughout the period from mid-September to the end of May. The frequency of molt for the animals was also observed.

2. Ovarian weights for intact crabs decreased from September to December and began to increase in January. The increase did not occur uniformly throughout the population, and by March all stages of maturation were present. First oviposition occurred in April, involving about 30% of the females. No oviposition occurred as late as mid-September.

3. Crabs that oviposited in April did not exhibit further vitellogenesis prior to molt which occurred in late May. A high frequency of molting again occurred in intact crabs in November and December.

4. Removal of eyestalks led to initiation of vitellogenesis in immature ovaries at all times tested and also appeared to increase the rate of vitellogenesis in already maturing ovaries.

5. Removal of eyestalks increased the frequency of molt maximally in September and late April and caused no increase in November and December or for post-ovigers in late May.

6. The pattern of reproduction and molt for this species in the months studied appears to consist of the following sequence: vitellogenesis-oviposition-incubation-hatching-molt. The breeding season could be extended by repetitions of the sequence or compressed by increasing the degree of synchronization.