REPRODUCTION IN THREE SPECIES OF INTERTIDAL BARNACLES FROM CENTRAL CALIFORNIA

Abstract

1. The reproductive cycles and brood production of Chthamalus fissus, Balanus glandula and Tetraclita squamosa from central California are compared. C. fissus produces about 16 small broods from March through October. B. glandula produces three to six relatively large broods from December or January to May. T. squamosa incubates only about three intermediate-sized broods from June through September.2. Brooding in C. fissus is regulated by food availability, and yolk for no more than one brood is stored at a time. Feeding in the laboratory elicited high brooding frequencies during periods when brooding activity and food levels in the field were low, and the frequency of brooding was directly proportional to the size of the food dosage. Temperature and photoperiod did not affect brooding frequencies. B. glandula rapidly stores nutrients in the ovary for about three broods during summer. Cold temperatures induce early brooding in the laboratory during late fall and early winter, and the population in the warm-water outfall showed delayed and lower brooding frequencies. Photoperiod did not affect brooding in B. glandula. T. squamosa in the warm-water outfall brooded six months earlier than the control population, suggesting warm temperatures are required for reproduction. Yolk for only one brood at a time is stored in T. squamosa.3. Comparisons of reproductive efforts estimated as brood weight relative to body weight per year show that C. fissus has proportionally the largest brood production; B. glandula an intermediate but large amount; and T. squamosa the smallest reproductive output.4. It is proposed that species of barnacles may be grouped into five categories based on major patterns of reproductive timing and brood production. The three species in the present paper show three of these patterns. The reproductive effort of these three species is compared with other cirripedes.