UQ scientists set out to find out how ‘clownfish’ see their world and howthat influences their behaviour.
The fish made famous in Finding Nemo can see ultraviolet (UV) light and
may use it as a ‘secret channel’ to find both friends and food, according toresearchers.
Anemonefish are easily recognised by their striking orange and whitepatterning, but University of Queensland scientists set out to find out how‘clownfish’ see their world and how that influences their behaviour.
Researchers at UQ’s Queensland Brain Institute (QBI) and the University ofMaryland in the United States analysed the visual systems of a particularspecies of anemonefish, Amphiprion akindynos.
QBI researcher Dr Fabio Cortesi said the Great Barrier Reef anemonefishwas basically Nemo’s cousin.
“We looked at everything starting with the genes they use to see and whatproteins they express, and in combination with anatomical data, predicted whatthese anemonefish can see,” he said.
“Proteins involved in detecting light have minute, well-known differences thatinfluence which wavelengths of light they absorb.”
QBI researcher Dr Fanny de Busserolles , who shares lead authorship on thestudy with Dr Sara Stieb , said the team was able to discover a uniquespecialisation in the eye of the fish that may allow them to better detectfriends and their anemone.
“In the part of the anemonefish’s eye that looks forward, the photoreceptorsdetect a combination of violet light and ultraviolet light,” Dr de Busserollessaid.
“They seem to be very good at distinguishing colour, and very good at seeingUV – it looks like they use it a lot.”
Dr Sara Stieb said the special ability made sense, based on the fish’senvironment and food source.
“Anemonefish live very close to the surface, where UV light can easilypenetrate,” Dr Stieb said.
“They live in symbiosis with anemones, and the anemones use UV to grow.
“Moreover, anemonefish feed on zooplankton which absorb UV light, so it wouldappear like dark dots against the background, making it easy to find.”
Dr Cortesi said UV vision lent anemonefish another important advantage.
“Their visual system seems to be very tuned to recognising who is their friendand who is not,” he said.
“The white stripes on anemonefish reflect UV, which means they should beeasier for other anemonefish to recognise.
“By contrast, a lot of the bigger fish – including ones that eat anemonefish –cannot see UV, so if you want to communicate on the reef over short distances,then UV is a very good way to do this.
“UV is essentially a secret channel that only these little fish can use totalk to each other,” he said.
“They can be as flashy as they want and they won’t be seen – and it might behow Nemo’s cousin finds its friends.”
The findings have been published in the journal Scientific Reports.
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