I spotted this amazing sight (see photo, right) in Croatia in July 2007. In light of New 杏吧原创鈥榮 book Does Anything Eat Wasps?, I鈥檇 like to know what鈥檚 going on here. Which insect is eating which, and is it common?
There is wide consensus on the family to which the predator belongs, but still some dispute over its exact identity and that of its prey 鈥� Ed
鈥� The smaller insect is a wasp (probably a potter wasp) and the other is a robber fly (Asilidae, probably of the genus Mallophora).
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Robber flies can grow to more than 2 centimetres long and are quite fearsome in appearance, with the orange tufts of hair around the face thought to protect it from its prey. This one is a wasp mimic and, as we can see, a killer.
They are known to attack large insects in flight, gripping the prey with their forelegs and then piercing it with their proboscis to inject a neurotoxin along with enzymes that break down proteins. The robber fly then lands and sucks the liquidised juices straight from the body of its prey. In this picture the wasp is in the process of being paralysed.
There are more than 7000 different species of robber fly. Some are fairly common, and few are as impressive as the one shown.
Peter Scott, School of Life Sciences, University of Sussex, Brighton, UK
鈥� Both insects are from the order Diptera. The larger is a robber fly of the family , which has caught a thick-headed fly of the family . The prey will be sucked dry by the attacker鈥檚 piercing mouthparts. The victim is not a wasp, but a wasp-mimicking fly. You can tell, as they both have only two wings (hence di-ptera) while wasps have four.
P. H. van Doesburg, Emeritus entomologist, Natural History Museum, Leiden, Netherlands
鈥� The picture shows a large robber fly, or asilid, eating a wasp. Apart from being a beautiful specimen of an impressive species, this wasp-eater is doubly interesting in that it seems to mimic a large spider-eating wasp from the Pompilidae family.
Asilids are better known for mimicking bumblebees. So why is this one mimicking a wasp? Pompilids are well behaved, but the large ones sting agonisingly if grabbed. So to mimic a pompilid offers a broad hint of danger. In fact, a stab from the beak of any large asilid is memorable, so if you are not an entomologist just admire them from a distance.
Most asilids sit on rocks or vegetation, ambushing passing food such as flies, butterflies, other asilids or, indeed, wasps. Some even rip spiders from their webs.
鈥淢ost asilids sit on rocks ambushing passing food, such as flies, butterflies, other asilids or wasps. Some even rip spiders from their webs鈥�
This behaviour is not as common as it once was. As wild territory shrinks, the loss of such species and their interrelationships is beyond the imagination of ecological incompetents. As a child I took asilids for granted. Nowadays, to see a nice big asilid is a rare treat.
Jon Richfield, Somerset West, South Africa
鈥� A few years ago my family, my friend and I visited a place called the Otter Pool on the Raider鈥檚 Road in Dumfries and Galloway in Scotland. As we sat eating our picnic in the summer sunshine, a dragonfly landed on my friend鈥檚 shirt sleeve. It had caught a wasp and was happily munching away.
The dragonfly stayed on my friend鈥檚 sleeve for around 5 minutes, until the entire wasp was consumed. My father filmed the event and you can see it at
Mark Jepson, By email, no address supplied