Female fish can breed a new species if they aren’t choosy about who is Mr. Right

Science Daily –

Fish will mate with a species outside their own if the male’s colouring is attractive enough or if the female can’t see him properly, according to new research.

Such ‘mistakes’ in mate choice can lead to the evolution of new species, an international team of scientists found. The group studied 2000 fish and analysed the DNA of more than 400 cichlid fish from two freshwater lakes in East Africa. They discovered more than 40 new species in Lake Mweru, which formed around one million years ago.

Dr Joana Meier, an evolutionary biologist at St John’s College, University of Cambridge, and lead author of the research published today (December 3 2019) in Nature Communications, said: “We found a dazzling variety of ecologically diverse new species — called radiations — that were previously unknown.

“The new species of cichlids adapted to use all the available food resources in the lake. Some feed on insect larvae, others zooplankton or algae. Some newly discovered fish are predators with large teeth, which we named ‘large-tooth serranchromines’.”

Many people assume fish are all the same species because they all live in water. But there are 30,000 different species of fish and many of them are markedly different from each other. Expecting them to mate outside of their own species is like expecting a horse to mate with a cat because they both have four legs and a tail.

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