Comparative feeding behavior of planktonic ctenophores.

The phylum Ctenophora (known as comb jellies) consists of gelatinous marine carnivores found from the surface to several thousand meters depth. Their morphology can be simple or complex, ranging from a sac-like shape with no tentacles to large lobed forms with sinuous "auricles," papillae, and two different kinds of tentacles. This diversity appears to reflect adaptations to many different diets. For example, some species can continuously "graze" on small crustaceans or larvae, others engulf larger jellies, and some are able to snare individual larger prey through a variety of strategies. Thus feeding behavior can help explain the high morphological diversity in this relatively small phylum. Because of their fragility, comb jellies are difficult to study alive and the natural histories of many types, especially those found in the deep sea, have not been examined. This account categorizes ctenophore feeding methods using published reports as well as new observations using submersibles and blue-water scuba diving.