Times of the Islands Winter 2022/23

green pages newsletter of the department of environment & coastal resources
prove this, further study demonstrating a mating preference
between flamingo tongues with the same pattern
would be needed.
Then there’s the supergene hypothesis, which the
belief that flamingo tongues have a supergene, or a
strongly linked set of DNA sequences that don’t often
get separated over generations and which code for certain
morphological features. This scenario can result in
common and rare morphologies within a species, the
common ones here being the spotted orange and black
circle pattern, and the rare being the fingerprint and broken
spot patterns. Many other hypotheses exist for the
differences in patterning, but all point to one fact: C. gibbosum
is a much more diverse and multi-faceted species
than meets the eye.
What’s more, beyond the eye-catching coloration of
C. gibbosum lies a violent and intriguing story. At first
glance, the spotted snail perched on the swaying sea fan
looks innocent—serene, even. However, a closer look
reveals a complicated picture of both predation and parasitism.
C. gibbosum is a predator in that it consumes
G. ventalina and other soft coral polyps for sustenance.
Because of this, the flamingo tongue is classified as a
“tissue-stripping tropical corallivore.” But the flamingo
tongue also lives on its prey. How is it possible for an
organism to maintain long-term residency on something
it chooses to eat? The answer is that C. gibbosum rarely
kills its hosts, eating it slowly enough that the prey is able
regenerate its lost tissues.
What this means is that C. gibbosum may not be a true
predator, but instead can be classified as an exoparasite,
a parasite that affects its prey from the outside. Unlike
some other parasites such as tapeworms or ringworms,
flamingo tongues do their damage without entering their
hosts. Flamingo tongues benefit from their sea fan’s
continued functionality, purposely inducing only small
amounts of damage on their prey/hosts. By not causing
total mortality in their prey/host, flamingo tongues have
found a way to gain a long-lasting home as well as a reusable
food source. Indeed, all life stages of this species
are dependent on their host: C. gibbosum individuals lay
their eggs on gorgonians, from which free-floating larvae
develop after a week, settling back onto gorgonian colonies
as juveniles.
Here, a flamingo tongue is predating on a soft coral. On the left, the
flamingo tongue foot is visible. On the right, the flamingo tongue has
crawled a small distance away, exposing the empty cavities (black
dots) of the coral polyps it has just eaten.
Another interesting aspect of this relationship
involves chemical warfare: Sea fans have evolved toxins
to ward off predation, which are effective against many of
their potential predators. Known as allelochemicals, these
substances are known in part for their bad taste, but
more so for their toxicity to many potential consumers.
While this scary-sounding collection of chemicals seems
like it would be too much for a little flamingo tongue, this
stubborn mollusc has evolved resistance to host chemical
defenses such as these. Recent studies have suggested
that marine consumers like the flamingo tongue can tolerate
toxin-laden prey through the presence of special
enzymes, biological catalysts that respond to specific
chemical signatures. While they serve many purposes,
enzymes in the flamingo tongue and other marine consumers
are believed to be able to neutralize the toxins in
sea fans to keep them from inflicting their catastrophic
effects.
With these methods allowing C. gibbosum to consume
their toxic prey, these molluscs don’t just survive,
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