Harlequin filefish avoid predators through the use of use of smell in an effort to avoid predators, according to a new study.
Oxymonacanthus longirostris is brightly colored, with gaudy dots and stripes that would make the animal stand out in most environments. Filefish, however, live among brilliant corals, which help to disguise the prey animals.
Filefish not only look like their coral environments, but smell like them, as well. Camouflage is usually associated with visual disguises, but this talent allows the animals another way to keep itself away from predators. Several other species also employ similar strategies in the battle for survival in the wild.
"Because predators often rely on odors to find their prey, even visually camouflaged animals may stick out like a sore thumb if they smell strongly of 'food'," Rohan Brooker of the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University, said.
Filefish eat coral, and their diet appears to influence the animals which choose to hunt the animals. Predators that consume O. longirostris were found to prefer those fish who ate coral local to their natural habitats.
"Crabs preferred the odour of filefish fed their preferred coral over the odour of filefish fed a non-preferred coral, suggesting coral-specific dietary elements that influence odour are sequestered," Royal Society Publishing reported.
In a case of "you are what you eat," filefish begin to smell more and more like local coral. As time goes on, crabs and other predators have a more difficult time distinguishing their target prey from surrounding coral.
"However, the filefishes' cover is blown if it shelters in a different species of coral than the one it has been eating. Then, the predators can distinguish it presence and track it down," Philip Munday of the Coral CoE, stated in a press release.
Many species of animals depend on their sense of smell as much, if not more, than sight. The combination of visual and odor-based camouflage appears to provide significant protection for O. longirostris, the researchers report.
By understanding more about the ability of filefish to use odor to avoid predation, biologists hope to learn more about the use of chemical signals by other species in the quest for survival. The use of chemical signals to "blend into" the environment by some invertebrates was previously known, but this was the first time the behavior was observed in higher animals.
Discovery of the role of coral smells by filefish was profiled in the journal Proceedings of the Royal Society B.
