Do dragonflies bite or sting?
The simple answer is NO. The full answer to this question has three parts:
(i) “Do dragonflies bite?” YES, dragonflies bite, because that’s how they capture their food. They have impressive, sharply pointed mandibles that chomp down on the smaller insects they catch.
(ii) “Do dragonflies bite people?” YES, if you catch one and hold it in your hand and carelessly allow its mandibles to reach your skin, it will bite as hard as it can in self defense. Very few dragonflies can even break the skin, but some of the big ones can do so and may induce an “ouch”. They’re certainly no danger to you, as the biggest dragonfly has a relatively small bite. A word of warning though: if, for some educational reason, you plan to let a dragonfly bite you, make sure you don’t suddenly pull back, as you’ll probably pull its head off and this is not a good example to present your audience!
(iii) “Do dragonflies bite people spontaneously?” A big resounding NO. A dragonfly would never land on someone and bite.
The simple answer to this is NO – they have no ‘sting’ as such. BUT there have been a number of accounts of egg-laying dragonflies that, when interrupted, continued the operation into the flesh or clothing of examining odonatists. Such actions could well be the origins of the many “old wives tales” pertaining to stinging dragonflies, and could also provide the answer as to why odonates have the names of ‘Horse-stingers’ and ‘Devil’s Darning Needles’. These names, and others like them, are part of dragonfly folk-lore in many parts of the world.
Philip Corbet (author of Dragonflies: Behaviour and Ecology of Odonata) drew our attention to the definition of a dragonfly in Samuel Johnson’s Dictionary (1755) as “a fierce stinging fly”: possibly the result of a painful experience?
Again basically, despite their ferocious appearance, dragonfly larvae do not harm people. However, late-instar larvae of larger species can use their mandibles to take a nip at an intrusive odonatist’s finger to give a noticeable poke. Cases have also been reported of loosely held larvae ‘stinging’ a researcher by turning its abdomen from side to side and inserting the sharply-pointed lateral spines into the intruder’s flesh.
The main thing to remember is that all animals do what they can to protect themselves and that odonates are no exception. Although even minor blood-letting is highly unlikely to be encountered, it is advisable to handle captured dragonflies with care. If one receives a nip, it is only too easy to react by involuntarily releasing the insect – and, of course, “the one that got away” is always the rarest and most-desired!
Dennis Paulson & Jill Silsby, lightly edited by Will Kuhn