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hot buttons for invertebrate defenses part of BCCR hot button for behavioral defenses part of invertebrate defenses in BCCR hot button for toxic chemicals part of invertebrate defenses in BCCR hot button for structure part of invertebrate defenses in BCCR
The topic considered here reating to defenses of invertebrates deals withbehaviour. Other invertebrate defenses are accessible via the icons.

Invertebrate defenses: behaviour

hot buttons for behaviour part of BCCR

Behavioural defenses in Caribbean invertebrates are many and varied, but can be roughly divided into the topics shown here.

This part of behavioral defenses includes associate with superior defense, involving reef invertebrates that hang out with other invertebrates that provide them with protection.


Invertebrate defenses: behaviour: associate with superior defense


seahorse dive leader for Biology of Caribbean Coral Reefs website

photograph of a cleaning shrimp with its host sea anemone taken from a video

"Who's doing a little dance over there? cleaning shrimps do this to attract client fish for cleaning, but I wonder why they live in anemones, and why they aren't eaten by their hosts?." - Turneffe Island 2000. Video courtesy Andy Stockbridge, Belize.

NOTE in this case, a Pederson cleaning shrimp Periclemenes pedersoni


A low-cost strategy to avoid predators is to live on or near a superior defense. As an example, several types of crustaceans live commensally with sea anemones or seek protective shelter under or within the spine canopies of large sea urchins. Coincidentally, many of the anemone- photograph of cleaner shrimps Periclimenes pedersoni with host sea anemone inhabiting crustaceans also clean fishes.

NOTE commensalism and other types of symbioses are considered in another section of BCCR: SYMBIOSES

NOTE cleaner shrimps and their clients are considered in more detail elsewhere: SYMBIOSES: MUTUALISM: CLEANER SHRIMPSphotograph of spotted cleaner shrimp with its host sea anemone

Pederson cleaner shrimps
Periclimenes pedersoni
among the tentacles of its host
sea anemone Lebrunia danae 0.5X

Spotted cleaner shrimps Periclimenes yucatanicus
live together with a variety of different sea anemones,
including the giant anemone Condylactis gigantea 2X


Several species of crabs live in association with sea anemones, presumably gaining protection from the stinging cells of their hosts. The relationship is usually thought to be commensal but, if the crabs bring food back with them after feeding excursions that is opportunistically eaten by their hosts, the relationship may actually be a mutualism.

Arrow crabs Stenorhynchus seticornis crawl widely throughout the reef, so while their presence in the sea urchin in the photograph below is suggestive of them seeking protection, there is no evidence that the association is not just a random one. Hayes et al. 1998 Bull Mar Sci 63: 241.

photograph of banded clinging crabs Mithrax cinctimanus living on their host sea anemone Condylactus gigantea   photograph of yellowline arrow crabs Stenorhynchus seticornis in a Diadema sea urchin
Banded clinging crabs Mithrax cinctimanus live in association with large sea anemones, such as Condylactis gigantea 1X   Several yellowline arrow crabs Stenorhynchus seticornis crawl within the spine-canopy of a long-spined sea urchin Diadema antillarum 0.33X
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of several wrasses seeking protection in a sea anemone, taken from a video "Lots of little fishes hang out in anemones. Here's a little goby, I think...oops, it's gone! Over here some wrasses... finding a safe haven amongst an anemone's tentacles. As long as they're careful not to get stung, they should be nice and safe." -

photograph of hermit crab courtesy Anne Dupont, Florida
Hermit crabs have several defenses, including biting claws and heavy exoskeletons, and the protective snail shells in which they live. But most interesting, and exemplifying association with a superior defense, are hydroids and sea anemones that reside mutualistically on their shells. Octopuses, for example, will shy away from touching hermit crabs with nematocyst-bearing cnidarians on their shells. The presence of hydroids may be adventitious, that is, dependent upon the larvae settling onto the shells, but many species of hermits will actively remove sea anemones from other locations and place them on their own shells presumably for defensive purposes. Photo courtesy Anne Dupont, FL.

NOTE a phylum including anemones, hydroids, and jellyfishes

Hermit crab Dardanus venosus with a protective
growth of stinging hydroids on its shell 0.5X

hot button for hide-away part of behavioral defenses in BCCR hot button for escape part of behavioral defenses in BCCR hot button for bite back/autotomy part of behavioral defenses in BCCR hot button for associate-with-superior-defense part of behavioral defenses in BCCR