Reproduction in three species of sea anemones from Key West, Florida

Abstract

Reproduction in three species of sea anemones from Key West, Florida, was studied from October 1977 until July 1978. Condylactis gigantea is dioecious, has a 1:1 sex ratio, and exhibits an oviparous → planktonic → lecithotrophic reproductive pattern, based on the scheme of Chia, modified by the author. Phymanthus crucifer is also dioecious and exhibits a sex ratio not significantly different from 1:1; however, this species is viviparous. Bartholomea annulata exhibits imperfect gynodioecious hermaphroditism, accompanied by asexual reproduction by pedal laceration; it is oviparous → planktonic → planktotrophic. It is argued that an oviparous habit with resultant larval dispersal is advantageous to C. gigantea, which is solitary. In contrast, viviparity in P. crucifer and pedal laceration in B. annulata represent two different methods of keeping offspring close, thereby maintaining habitat space. The evolution of three such diverse reproductive modes is discussed through an examination of the morphology, prey, and habitat type of each species.