Meeting Abstract

S8.8  Thursday, Jan. 6  Predator and conspecific induced hatching in a marine snail MINER, BG*; DONOVAN, DA; MORGAN, C; Western Washington University; Western Washington University; Western Washington University

Inducible defenses are well studied in adult marine invertebrates. Some of the pioneering studies by Harvell, Lively, and Palmer on inducible defenses demonstrated that adult marine invertebrates can detect predators and adjust their morphology to better defend themselves. By contrast, little is known about inducible defenses in earlier life-history stages. In some non-marine species that place embryos in a gelatinous mass, early life-history stages can induce defenses against predators by altering when they hatch. We became interested in whether embryos of marine invertebrates can also adjust when they hatch. Many species of marine invertebrate, spread across the metazoan phylogeny, have embryos that develop in a keratin-like capsule or gelatinous mass. Using embryos of a common Northeastern Pacific, intertidal whelk (Nucella lamellosa) and a common crab that consumes whelk capsules (Hemigrapsus oregonesis), we tested whether a marine organism can adjust time-to-hatching in response to a predator. We found that whelk embryos possess predator-induced hatching plasticity—embryos delayed hatching in respond to predators. These results and the phylogenetic distribution of predator-induced hatching plasticity suggest that predator-induced hatching plasticity has likely evolved more than once. In an attempt to determine whether waste from the predator slowed development in whelk embryos and explained the delay, we discovered that adult, conspecific snails accelerate hatching in whelk embryos. Despite the few studies on conspecific-induced hatching plasticity, we suggest that this response is common for organisms with embryos that compete with other hatchings. We will discuss the evolutionary and ecological consequences of these results.