BROODING BEHAVIOR OF A SIX-RAYED STARFISH, LEPTASTERIAS HEXACTIS

¹ Department of Zoology and the Friday Harbor Laboratories, University of Washington, Seattle, Washington

1. The brooding habit is apparently necessary for these animals; none of the embryos survived without brooding.

2. The main functions provided by brooding are protection, cleaning, maintenance of a uniform environment, and initiating the hatching process.

3. During brooding, the animals are particularly sensitive to the substratum. They not only favor the under and vertical surface of rocks, but also prefer the darker-colored and rougher-surfaced rocks.

4. At the time of brooding, Leptasterias hexactis stops feeding completely, but the animals will take food after a latent period of two days if the embryos are removed from the brooding chamber. Thus, a constant stimulation by the embryos is apparently necessary to prevent the animals from feeding.

5. During the breeding season, all the adult animals (female, male, spawned and non-spawned) are able to recognize their embryos and will pick them up to brood. This recognition is not due to the size, color, or shape of the embryo masses but rather to the physical nature of the fertilization membrane.

6. The significance and possible control mechanism of brooding were discussed.