Swarming male locusts use bright yellow coloration to avoid mistaken sexual identity.

What is it about?

Young crowded locusts are black and yellow, signalling to potential predators - "Leave me alone!" At sexual maturity, swarming males turn yellow again - but why? This has been a mystery for over a century. We suppressed the "Yellow Protein" in mature, amorous males, which caused them to mistake each other for female and attempt to mate one another. So yellowing is repurposed, from a warning to predators into a warning to sexual rivals. This might well be unique to locusts. By contrast, lone-living locusts never turn yellow, so the entire warning strategy (to predators or sexual rivals) is density-dependent. Yellow Protein might therefore help to unravel how nature (the gene) and nurture (the crowd) combine to control an animal's life history.

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Photo by Ed van duijn on Unsplash

Photo by Ed van duijn on Unsplash

Why is it important?

The reason for yellowing in male locusts has remained a mystery for over a century. Our work adds a sexual dimension to studies of locust swarming behavior, and highlights how much we still need to learn about fundamental behaviors in these animals.

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