Shadows 'scare' fruit flies
Fruit flies will not instinctively take flight to be safe, but they experience an unpleasant sensation much like human fear, according to new experiments carried out by US scientists.
The scientists scared fruit flies away from some food with a fan that briefly cast a shadow on them just like in the case of an attack by flying predators. The threat made the flies take flight in a kind of panic, by which they sped about in confusion, until returning to their meal after a few seconds. However, the creatures did not react in the same way every time. The more times the shadow was cast on the insects – indicating that more than one creature was attacking – the faster, longer, and more panicky the flight. As the insects’ reactions differed depending on the magnitude of the threat, scientists conclude that the flies act out of fear and not only by reflex.