We all want a bit of L-O-V-E, from homo sapiens, through to dolphins and of course the various sub-groups of the Heliconius toxic butterfly species.

Scientists are intrigued by two central American sub-species in particular  – the red-winged Heliconius Melpomene Rosina and the white-winged Heliconius Cydno Chioneus. This pair have been part of the same ecosystem for a million years and competed for the same resources and yet have remained genetically distinct with very few instances of interbreeding.

One evolutionary explanation posits that these species haven’t blended through the generations because any off spring would have a blend of wing patterns. This would be a free-for-all for other predators who only identify danger in the distinct red or white-winged patterns of Melpomene and Cydno respectively. Therefore, being an easy target means hybrid butterfly babies don’t live long enough to pass on their own mixed genes.

But why won’t Melpomene and Cydno get it on? The recently published journal PLOS biology attributes this lack of romance to genetics. The team of researches believe to have  found which parts of the genome determine mating preferences.

It’s also understood that there is a link between wing patterning and mating preference. The genes that are said to have an influence on mating preference are located very close to the Optix which is responsible for the colouring of the butterfly species’ wings. Although this is not firmly understood, scientists are optimistic that cameras and machine learning will help identify exactly what the processes are.

This case in genetics is called ‘reproductive isolating’ and it’s definitely a great topic for biologists to explore in their personal statements and interviews.

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