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Cryptodendrum adhaesivum

Sticky Anemone



Fact Sheet



Physical Description



Life History & Behavior

Feeding Behavior


Reproduction and Development


Response to Light Changes

Anatomy & Physiology

Circulatory and Excretory Systems

Defense Mechanisms: Cnidocytes and Cnidae

Digestive System

Nervous and Sensory Systems

Skeleton and Musculature

Evolution and Systematics

Biogeographic Distribution

Conservation and Threats

References and Links

Feeding Behavior

Figure 1. Sequence of behaviors that occur during the capture and ingestion of a single prey item. A: tentacles are extended and pharyngeal ciliary currents are directed out of the coelenteron (arrow). B: upon contact with a tentacle the prey is immobilized by cnidae, and the tentacle folds towards the mouth. C: the tentacle shortens. D: local contraction of oral disc and radial muscles occurs. E: the retractor muscles in the mesenteries contract, causing the mouth to protrude towards the prey. Circum-oral swelling, mouth opening and reversal of the pharyngeal ciliary current (arrows) are stimulated by chemicals given off by the prey, which results in it being ingested. Adapted from Holley & Shelton (1984).

Sea anemones are the epitome of sit-and-wait predators, which minimizes putting energy into searching for food. The general anemone relies on water motion or prey locomotion until food is within reach of its capture surfaces. Pre-feeding responses such as expansion of the oral disc, opening of the mouth and protrusion of the actinopharynx1, and extension and twitching of tentacles may be stimulated by water soluble components of prey. The anemone then waits for sessile prey dislodged by foraging predators or wave action to fall onto their tentacles or oral disc, or simply grabs onto motile prey that swim into its tentacles. Tentacles are equipped with cnidae (see Defense Mechanisms) that assist in prey capture by wounding and immobilizing the prey1. It may also feed on planktonic prey that is moved to its tentacle tips by ciliary action, which are then inserted into its mouth(Figure 1).

A spatially separate range of mechano- and chemoreceptors differing in thresholds, specificites and effectors are noted to be involved in the complete sequence of feeding behavior, which begins with the perception of food and ends at its ingestion. Effectors such as muscles can be coordinated by electrical conduction systems. On the other hand, effectors such as pharyngeal cilia apparently do not involve any electrical conduction system during pharyngeal ciliary reversal at the actinopharynx4 (see Digestive System). Behavioral studies have indicated that the chemoreceptors involved in various feeding behaviors are situated on the tentacles, oral disc, peristome and actinopharynx, but this may differ with some species1.

In the case of C. adhaesivum, it is both carnivorous and a filter feeder, and will feed on chopped fish or shrimp4. Its tissues also contain symbiotic zooxanthellae that can photosynthesize5 (see Digestive System for more detail).

1Shick 1991
2Ruppert, Fox & Barnes 2004
3Holley & Shelton 1984
4Sprung 2001
5Wallace & Richards 2007