Temporal activity patterns in reef-dwelling stomatopods: a test of alternative hypotheses

摘要: Abstract Observations showed that two species of stomatopods, Gonodactylus oerstedii Hansen and G. spinulosus Schmitt, from shallow reefs in Saint Croix, Virgin Islands, U.S.A., exhibited a strong daily activity pattern. These mantis shrimps emerged their burrows for longer periods time moved further at dawn dusk than during midday. They also exposed bodies as far the carapace or abdomen significantly more frequently midday, although overall number times they appeared entrance did not vary with day. All sealed themselves inside burrow all night. We hypothesized these patterns resulted availability prey, activities fish predators, visual capabilities stomatopods. Stomatopods fed primarily on small crustaceans, gastropods polychaetes. feeding behaviors, volume food stomachs rate which it was processed indicated reef predators feed selectively particular Quantification benthic prey different day confirmed items determine crepuscular pattern The extreme abundance data eaten suggest does limit populations shrimps. What is known structure function eyes gonodactyloid stomatopods indicates are adapted to relatively bright light conditions. Our produced no evidence were active because could see avoid better twilight differentially responding observer absence nocturnal however, probably reflects inadequate vision. Repeated close observations other physical factors (temperature, tides, wave action) had apparent effect upon patterns. Censuses fishes less abundant study sites Invertebrate-eating numerous midday dusk. body sizes “invertivorous” smallest dusk, reducing potential predation time. A “quiet period”, where diurnal have retired but yet (or converse), previous studies coral fishes, present provides first documentation inversely correlated organisms.