Acquisition and use of nematocysts by cnidarian predators

Abstract

Although toxic, physically destructive, and produced solely by cnidarians, nematocysts are acquired, stored, and used by some predators of cnidarians. Despite knowledge of this phenomenon for well over a century, little empirical evidence details the mechanisms of how (and even why) these organisms use organelles of cnidarians. However, in the past 20 years a number of published experimental investigations address two of the fundamental questions of nematocyst acquisition and use by cnidarian predators: (1) how are cnidarian predators protected from nematocyst discharge during feeding; and (2) how are the nematocysts used by the predator?

Fig. 1

TEM of ceratal epithelium from the aeolid nudibranch Spurilla neapolitana. Chitinous spindles (arrows) are crowded into each epithelial cell. Numerous microvilli (MV) cover the ceratal surface, and a distinct basal lamina (BL) lies below the epithelial cells. A basal nucleus of one epithelial cell is indicated (N).

Fig. 2

Illustration of a ceras tip from the nudibranch Spurilla neapolitana in longitudinal section. Although ceratal sizes and shapes differ among nudibranch species, the general features of the cnidosac are similar. Cnidophages of S. neapolitana average about 70 μm in length.