. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SESARMA REPRODUCTIVE ECOLOGY 397. 2000 Figure 12. Number of individual Sexanna sp. (nr. reticulatum) vid- eotaped releasing larvae versus time of release, in videomonitored ex- periment. months. Dirty egg masses (often infested with peritrichous ciliates, nematode worms, and the harpacticoid copepod Cancricola plumipes Humes, 1941) seemed to be more prevalent in the warmer summer months. Many decapods groom their egg masses, but this behavior is relatively un- common in brachyuran crabs (see review by Bauer, 1989) and seems
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SESARMA REPRODUCTIVE ECOLOGY 397. 2000 Figure 12. Number of individual Sexanna sp. (nr. reticulatum) vid- eotaped releasing larvae versus time of release, in videomonitored ex- periment. months. Dirty egg masses (often infested with peritrichous ciliates, nematode worms, and the harpacticoid copepod Cancricola plumipes Humes, 1941) seemed to be more prevalent in the warmer summer months. Many decapods groom their egg masses, but this behavior is relatively un- common in brachyuran crabs (see review by Bauer, 1989) and seems to be particularly uncommon in the more ter- restrial species such as grapsids and ocypodids. Cycles within the reproductive season were correlated with the new and full periods (syzygies) of the lunar month. Such semilunar timing of larval release, so as to correspond to spring tides, is hypothesized to be an ad- aptation that facilitates export of larvae out of estuaries in Uca sp. (Sandifer, 1975; Christy and Stancyk, 1982). However, Sandifer (1975) found larvae of Sesarma reti- culatum concentrated near the bottom, which would fa- cilitate retention within an estuary. Larval release during spring tides in this species, and possibly 5". sp. (nr. reti- culatum}, would enable females to release larvae under the protection of high tide in upstream areas not strongly affected by tides at other times, and may transport larvae out of marshes, ditches, and tidal creeks, and into deeper water. For mature larvae to be released coincident with op- timal conditions for their survival ( tides at new or full moons), eggs must be produced and laid in adequate advance of some developmental period, the duration of which itself varies according to exogenous factors (, temperature). Thus, selection would most likely favor egg- laying rhythms coincident with lunar phase but modulated to precede new and full moons by a time period that rep- resents the mean period of embryonic dev
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
