REPRODUCTION AND DEVELOPMENTAL VARIABILITY IN THE OPISTHOBRANCH TENELLIA-PALLIDA

Pelagic and non-pelagic development occurs within a single population of the nudibranch Tenellia pallida (Alder and Hancock) from South Carolina (USA). Both developmental types occurred simultaneously, under identical conditions, and without the aid of nurse eggs. Adults laid either ≈70 μm diameter eggs that hatched as pelagic (planktotrophic?) veligers in 68 to 122 h, or ≈100 μm diameter eggs that became well-developed veligers, metamorphosed within their egg capsules, and hatched as shelled juveniles in 140 to 190 h (15°C, 30‰ S). Adults that produced pelagic larvae laid more eggs per day and per egg mass and twice the daily egg volume produced by adults of the opposing type. © 1979 Springer-Verlag.