Sexual Reproduction in the Colonial Kamptozoan Barentsia hildegardae

Abstract

Four aspects of sexual reproduction were examined in a northeastern Pacific population of the kamptozoan (entoproct) Barentsia hildegardae. The investigation of this colonial species revealed that (1) the population was sexually mature year-round, with a peak of sexual maturity during summer; (2) the sex ratio of the calyces in this population did not differ significantly from 1:1 male:female; (3) male colonies grown on glass slides had higher proportions of sexually mature calyces than did females and the zone of maturity extended farther toward stolon tips; (4) recruitment was much higher near female than male colonies, perhaps because brooded larvae settled near their mothers almost immediately after release. Additional key words: Entoprocta, sexual maturation, reproductive period, sex ratio, larval period Understanding the life history of a colonial animal can be complicated, because processes such as growth, reproduction, and death must be examined at multiple levels (zooid, colony, and whole genet). Moreover, determining colony (and genet) boundaries in the field is often impossible. Consequently, we know far less about the life histories of colonial animals than about their unitary counterparts. Learning even basic information about colonial life histories, however, is essential for evolutionary and ecological studies of colonial