Coloration of reef organisms
 
column spacer Coloration of reef organisms
  hot buttons for colours section of Biology of Caribbean Coral Reefs website
This section deals with the function of colours. Topics of HOW COLOURS ARE CREATED and HOW COLOURS ARE PERCEIVED can be accessed via the icons.
 
 

Function of colours

  Functions of colours and colour patterns in reef animals fall into 2 broad categories of SOCIAL and defense, considered here, the latter including the possibility of UV protection. Most or all of these topics have been mentioned elsewhere in the BCCR but, by its nature, this section on FUNCTION OF COLOURS pulls them together as a broad summary. CLICK ON a topic to learn about it.
 
 
 

Function of colours: defense: warning of toxicity

 

We know from other parts of the VIRTUAL DIVE that camouflaging in reef organisms can involve combinations of colour, form, and behaviour. What follows in this section are some examples where colour and colour-patterns predominate. This large topic is divided into a section on zoanthids considered here, and sections on SEA ANEMONES JELLYFISHES & HYDROIDS, SNAILS, and FISHES presented elsewhere.

NOTE see DEFENSES: INVERTEBRATES: BEHAVIOUR: HIDE AWAY/CAMOUFLAGE

 
 

Zoanthids

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of zoanthids

"I'm over here looking for a sponge with zoanthids growing on it, but I'm finding other weird stuff. Look at the scar where the sponge has been rubbing. And what on earth is this? Could it be a bite...or a knife cut? Very strange!" - Bonaire 2008

NOTE branching vase sponge Callyspongia vaginalis

 
 

photograph of sponge covered with zoanthids with a chunk bitten out of it
Zoanthids are known to be highly toxic and are excellent overgrowth competitors. At least one species overgrows the surface of sponges and often contrasts markedly in colour with that of its host. Interestingly, the host sponges often rank high amongst those favoured by spongivorous fishes like angelfishes. The question is, what is the functional significance of the symbiosis? Is it parasitism, or mutualism? Is warning coloration involved, perhaps involving protection of both the zoanthid and the sponge? West 1976 p. 443 In, Ceolenterate ecology and behavior (ed. Mackie).

NOTE for more on this subject to to CORALS/ZOANTHIDS: OVERGROWTH COMPETITION

 

 

The predator that ate this pink vase sponge Niphates digitalis also ate
quite a few polyps of sponge zoanthids Parazoanthus parasiticus that
were living on the surface of the sponge 0.5X Did the toxicity of the
zoanthids not influence the predator's selection of this particular
sponge as food? Did it become sick after eating? If so, will it
have learned that the presence of the zoanthid is a warning
of bad things about to happen in a digestive- tract way?

 
cartoon 1 in a series of 12 concerning warning coloration in zoanthids
 
 
To find out more about the relationship of zoanthid and sponge, and whether warning coloration is involved, let's listen in to the SCUBA-diver discussing it with a zoanthid polyp inhabiting a sponge:
 
cartoon 2 in a series of 12 concerning warning coloration in zoanthids cartoon 3 in a series of 12 concerning warning coloration in zoanthids
cartoon 4 in a series of 12 concerning warning coloration in zoanthids cartoon 5 in a series of 12 concerning warning coloration in zoanthids
cartoon 6 in a series of 12 concerning warning coloration in zoanthids cartoon 7 in a series of 12 concerning warning coloration in zoanthids
cartoon 8 in a series of 12 concerning warning coloration in zoanthids cartoon 9 in a series of 12 concerning warning coloration in zoanthids
cartoon 10 in a series of 12 concerning warning coloration in zoanthids cartoon 11 in a series of 12 concerning warning coloration in zoanthids
  NOTE zoanthids multiply on the sponge by asexual budding, so all such "offspring" are genetically identical clones. For more on this topic see RECRUITMENT: ASEXUAL REPRODUCTION: CORALS/ZOANTHIDS
 
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