Colour pattern spurs speciation in tropical fish

May 28, 2007

McGill researchers discover that coral reef fish colour patterns are responsible for the emergence of new species
A team of researchers from McGill University and the Smithsonian Tropical Research Institute (STRI) has provided the first example of how colour patterns on a coral reef fish species can drive its evolution into many distinct species.

“These fish were the unusual suspects for a model explanation of how new species arise,” said lead author Oscar Puebla, a PhD student in the Neotropical Environment Option (NEO), a collaboration between McGill and STRI. “When investigating ecological speciation, the first reflex is to look at the species’ environmental conditions rather than at its behavioural traits.”

The researchers looked at feeding and mating behaviours based on colour patterns to explain the emergence of several species of hamlet fish (genus Hypoplectrus). Predatory Hypoplectrus fish were observed tracking other non-predatory fish species with similar colour patterns to surprise their prey, which are usually not afraid of non-predatory fish species. They were also observed mating with partners with similar colour patterns. Having identified behaviours that segregate the fish into groups and small but statistically significant genetic differentiation, the researchers concluded that each of the 13 colour morphs of hamlet fish classifies as an incipient species. Their findings appear in the May 22 issue of Proceedings of the Royal Society of London B. Supporting online materials include videos of fish behaviour.

“This group of fish was really a mystery,” said Dr. Frederic Guichard, assistant professor in the Department of Biology at McGill. “Genetic variation alone was not strong enough to identify species among fish of different colour patterns and there were no obvious ecological mechanisms at first. We were at the frontier of our ability to detect new species and speciation.”

Guichard explained that classic cases of ecological speciation offer more straightforward mechanisms of speciation. For example, Darwin’s finches became different species because their beak morphology was associated with specific seed diets and unique mating calls.

In this study, distinct neon colour patterns on Hypoplectrus fish highlighted their distinct behaviour. But patterns of behaviour only became evident to Puebla’s team after scuba diving across 94,000 square metres of reef habitat in Panama, Belize and Barbados. Puebla calculated that “during a one-hour dive, you will observe on average colour-based behaviour for only six minutes.”

Puebla hopes that this study provokes more daring research into ecological speciation. “One of the messages of the paper is that you have to look for the rare behaviours that may have a disproportionate ecological and evolutionary significance. You can’t just take a snapshot of the species; you have to spend long hours in the wild studying them.”

Funding for this study was provided by the Smithsonian Institute’s Marine Science Network.

Supplemental video 1

Supplemental video 2


Source: McGill Unive

Explore further: New Indonesian crayfish species escapes the decor market to become a freedom fighter

Related Stories

Ocean threat from Hong Kong's taste for seafood

August 10, 2015

A seafood lunch in Hong Kong is enjoyed by locals and visitors alike, but with threatened species on the menu and fishing practices that endanger marine life, campaigners want to change the city's appetite.

Volcanic vents preview future ocean habitats

August 10, 2015

A world-first underwater study of fish in their natural environment by University of Adelaide marine ecologists has shown how predicted ocean acidification from climate change will devastate temperate marine habitats and ...

Recommended for you

Fossil specimen reveals a new species of ancient river dolphin

September 1, 2015

The careful examination of fossil fragments from Panama has led Smithsonian scientists and colleagues to the discovery of a new genus and species of river dolphin that has been long extinct. The team named it Isthminia panamensis. ...

Early human diet explains our eating habits

August 31, 2015

Much attention is being given to what people ate in the distant past as a guide to what we should eat today. Advocates of the claimed palaeodiet recommend that we should avoid carbohydrates and load our plates with red meat ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.