Why is a tropical bug waving tiny red flags? Scientists finally have an answer

Why is a tropical bug waving tiny red flags? Scientists finally have an answer (Image: Canva)

Scientists at the Smithsonian Tropical Research Institute have discovered that the matador bug (Bitta alipes) waves its conspicuous red hind legs as an anti-predator strategy. The research challenges the long-held idea that the behaviour was linked to sexual selection.

The team recorded nearly 3,000 leg-waving events in controlled trials, carefully monitoring how bugs responded to different insects. The study was carried out in Panama, where matador bugs live on passionflower vines in tropical forests.

When did the waving occur?

The insects waved dramatically when placed with praying mantids, which are predators, but showed little response when paired with harmless katydids. On average, waving increased seven-fold in the presence of mantids. Crucially, mantids never attacked bugs that were actively waving.

(Image: x/@stri_panama)

Why does this matter?

Since males and females alike waved their legs and it had nothing to do with flirting or fighting, scientists say the move is all about staying safe. It’s another reminder that even tiny bugs can come up with clever tricks to keep predators at bay. The finding offers a glimpse into how even the smallest creatures come up with smart strategies to stay alive in the wild.

How does it work in nature?

The exact mechanism remains uncertain. The waving may function as a warning that the insect is unpalatable, especially since related species feed on passionflower vines, which sometimes contain toxins. Alternatively, the movement might confuse predators’ vision or make the bug appear larger and riskier to attack. Interestingly, at least five other flag-legged species also show similar behaviours.

For the rainforest’s matador bugs, the red flag is not a love signal but a clever shield against danger.