Gut evacuation of larval Mnemiopsis leidyi A. Agassiz (Ctenophora, Lobata)

Abstract

Despite their potential importance as predators, the early life-history stages of ctenophores are relatively understudied. Measurements of digestion times for larvae are especially limited compared with adults, even though these measurements are required to calculate feeding rates using gut content analysis. This study reports digestion times for larval Mnemiopsis leidyi for a wide range of prey. Larval M. leidyi consumed the copepodite and naupliar stages of copepods, polychaete larvae, bivalve larvae, rotifers, rotifer eggs, ciliates and flagellates. Digestion times varied significantly among prey taxa and ranged from ∼1 min for aloricate ciliates to 2 h for copepodites. Although ciliates and flagellates are frequently observed in ctenophore guts, feeding on protistan microplankton cannot be quantified adequately using gut content analysis because these prey items are often digested too rapidly to be identified in ctenophore guts.