A species of small fish uses a homemade coral-scented cologne to hide from predators, a new study has shown, providing the first evidence of chemical camouflage from diet in fish.
Filefish evade predators by feeding on their home corals and emitting an odor that makes them invisible to the noses of predators, the study found. Chemical camouflage from diet has been previously shown in insects, such as caterpillars, which mask themselves by building their exoskeletons with chemicals from their food. The new study shows that animals don't need an exoskeleton to use chemical camouflage, meaning more animals than previously thought could be using this survival tactic.
"This is the very first evidence of this kind of chemical crypsis from diet in a vertebrate," said Rohan Brooker, a post-doctoral fellow in the School of Biology at the Georgia Institute of Technology in Atlanta. "This research shows that you don't need an exoskeleton that for this kind of mechanism to work."
The study was published December 10 in the journal Proceedings of the Royal Society B. The study was sponsored by the ARC Centre of Excellence for Coral Reef Studies and the Ecological Society of Australia. The work was done as a part of Booker's doctoral research at James Cook University in Australia.
Anyone who has watched a nature documentary has seen insects that camouflage themselves as sticks, protecting the insects against predators that use vision to hunt for prey. But many animals see the world through smell rather than sight, and cunning critters from among them have adapted clever ways of smelling like their surroundings. A certain species of caterpillar, for example, smells like the plant that it lives on and eats. The caterpillar incorporates chemicals from the plant into its exoskeleton. Ants hunting for the caterpillar will walk right over it, none the wiser.
For the new study, researchers traveled to Australia's Lizard Island Research Station in the Great Barrier Reef, where they collected filefish. To show that filefish smelled like their home coral, the researchers recruited crabs to sniff them out. The filefish were fed two different species of coral; each species of coral is home to a unique species of crab. The crabs were given a choice between a filefish that had been fed the crab's home coral and a filefish that had been fed a coral that is foreign to the crab. The crabs always sought the filefish that had been feeding on the crabs home coral. The filefish smelled so strongly of coral that sometimes the crabs were attracted to the fish instead of coral, when given a choice between the two.
"We can tell that there is something going through the filefish diet that's making the fish smell enough like the coral to confuse the crabs," Booker said.
To see if the chemical camouflage gives the filefish an evolutionary advantage to evade predators, the researchers tested cod to see how they responded to filefish that had been fed various diets. Cod, filefish and corals were put in a tank, with the filefish hidden from the cod. When the filefish diet didn't match the corals in the tank, the cod were restless, suggesting that they smelled food. When the filefish diet matched the corals in the tank, the cod stayed tucked away in their cave inside the tank.
The next step in the project is to learn how filefish can smell like coral without the benefit of an exoskeleton. Some evidence shows that amino acids in the mucus of fish - where much of their smell originates - will match their diet, but much work remains to tease apart this pathway.
"We have established that there is some kind of pathway from filefish diet to filefish odor," Booker said. "This is just the first study. There's a lot of work still to be done to understand how it works."
Booker is now working in the lab of Danielle Dixson, an associate professor of biology at Georgia Tech.
This research is supported by the ARC Centre of Excellence for Coral Reef Studies and the Ecological Society of Australia. Any conclusions or opinions are those of the authors and do not necessarily represent the official views of the sponsoring agencies.
CITATION: Rohan Brooker, et al., "You are what you eat: diet-induced chemical crypsis in a coral-feeding fish." (Proceedings of the Royal Society B, December 2014). http://rspb.royalsocietypublishing.org/content/282/1799/20141887
Georgia Institute of Technology
177 North Avenue
Atlanta, Georgia 30332-0181 USA
Media Relations Contacts:
Brett Israel (@btiatl) (404-385-1933) (email@example.com) or
John Toon (404-894-6986) (firstname.lastname@example.org)
Writer: Brett Israel
Brett Israel | EurekAlert!
New application for acoustics helps estimate marine life populations
16.01.2018 | University of California - San Diego
Unexpected environmental source of methane discovered
16.01.2018 | University of Washington Health Sciences/UW Medicine
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
16.01.2018 | Materials Sciences
16.01.2018 | Materials Sciences
16.01.2018 | Power and Electrical Engineering