Toxicity and taste: unequal chemical defences in a mimicry ring.

Sea slugs show that tastes can be deceptive

26 October 2018

Many poisonous animals sport colourful skin patterns, which predators learn to avoid after experiencing the poisonous prey’s nasty taste. As such, toxicity and taste were thought to be related. But researchers have now found that the palatability of sea slugs might not betray how dangerous they are to potential predators.

A team, including researchers from Deakin University, studied the genetics of several species of red spotted sea slug, some of which were toxic. Despite their similar skin patterns, they were not all members of the same family; some merely mimicked the toxic slugs.

The team analysed tissue samples from each species and found they contained different defensive chemicals at different strengths. When they fed extracts of each species to shrimp, they found that, although some slugs were more toxic to shrimp than others, they were all similarly unpalatable.

Future studies of mimicry among animals with chemical defences should more carefully distinguish between taste and toxicity to ensure all potential defence techniques are tested.

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References

1. Proceedings of the Royal Society B 285, 20180457 (2018). doi: 10.1098/rspb.2018.0457