Inter-Research
Marine Ecology Progress Series

ABSTRACT: The opisthobranch Haminaea callidegenita has poecilogonous development (i.e. produces more than 1 type of offspring) based on swimming ability, and therefore dispersal potential, of offspring. Both swimming veligers (non-feeding) and crawling juveniles were simultaneously released from almost every egg mass (EM) (97%) indicating that development mode varied among the offspring of single individuals as well as throughout the population. Development of all offspring per EM appeared to be identical until just prior to hatching when approximately half of the siblings metamorphosed and hatched as juveniles. The remaining siblings hatched as veligers and metamorphosed after a planktonic period ranging from 1 to 30 d. Variable hatching appears to be typical in this species because it occurs in almost every EM, is independent of some environmental variables, and many hatched veligers have a relatively long planktonic period before becoming competent. The percentage of juvenile hatchlings was highly variable among EM (ranging from 4 to 100%). Variability in hatchling type occurred among clutches, populations, and years. Also, hatchling type was influenced by a 'poor' parental environment in that food deprived females initially produced more swimming larvae than did control females. The percentage of juveniles released per EM was otherwise conservative in that it was not influenced by many of the other factors tested including: physical EM characteristics, female reproductive traits (fecundity, female size, egg size), time of year, source of metamorphic inducer and culture conditions.

KEY WORDS: Poecilogony . Developmental variability . Larval ecology . Opisthobranch

Published in MEPS Vol. 121 (1995) on May 25
Print ISSN: 0171-8630; Online ISSN: 1616-1599. Copyright © Inter-Research, Oldendorf/Luhe, 1995