The Redder a Ladybug, the More Deadly She is to Predators

Illustration: Charley Harper

Watch out, birds, that lady’s poison. The redder a ladybug’s wings, the more deadly she is to predators. Same goes for her male counterpart, according to British researchers.

The team studied seven-spot ladybugs, comparing well-fed individuals to those they intentionally undernourished. “Better-fed ladybirds were redder and more toxic, and levels of color and toxicity correlated,” says lead researcher Jon Blount.

The discovery shows that food abundance, coloration, and defenses are more intricately linked than previously thought. Producing both warning signals and chemical defenses requires chowing down on a lot of aphids, and cheaters don’t prosper.

“Individuals that signal dishonestly, producing very red coloration without investing in similarly high levels of toxicity, would likely get found out,” says Blount. “Predators regularly sample prey populations.” Though a human eye can’t spot the hue differences, it’s likely obvious to keen-eyed birds and other animals seeking a snack.

This story originally ran in the May-June 2012 issue as, “Lady in Red.”

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