Limits to the Prolonged Planktonic Life Among Larvae of Tropical Benthic Invertebrates and Its Biogeographic Consequences

点击翻译按钮获取中文摘要

The widespread existence of teleplanic or "long distance" larvae of sublittoral invertebrates in the tropical epipelagic waters of the central Pacific, Atlantic and Indian Oceans supports the hypothesis that larvae contribute importantly not only to initial colonization of oceanic islands and, more generally, to the present continuous or disjunct ranges of such species, but also to the continuing genetic exchange among islands or even between islands and far distant continental populations. However, no one has yet demonstrated in any systematic way that teleplanic larvae are capable of metamorphosing at the time of their collection in the open sea. We do not yet know whether teleplanic larvae are physiologically adapted for remaining planktonic over long periods of time or whether the lack of further growth already documented instead is due to low phytoplankton concentrations in the open ocean. The future research will address these two questions 1) by obtaining larvae in the open ocean and ascertain experimentally whether or not these larvae are competent to metamorphose, (2) by maintaining larvae in the laboratory to determine whether individuals that would not metamorphose in the sea eventually become competent to metamorphose, and 3) by determining whether or not teleplanic larvae are physiologically capable of further growth given adequate phytoplankton concentrations or alternatively whether growth stasis, i.e., a quasi-holoplanktonic state, is achieved.