Jackals fly in for a feast
Gary Farmer and Nicki Farmer
On 21st June we were walking adjacent to the river Avon near Evesham Country Park, enjoying the abundant Banded Demoiselles, marvelling at an agile Hobby chasing Swallows along the river, listening to a Turtle Dove calling, and the sun was shining; it couldn’t get any better? But then we noticed a Honeybee struggling to escape from the jaws of a large spider Misumina vatia. And then we noticed a group of small flies homing in on the spider and its prey. They landed on the bee and even on the spider itself and started feeding on the bee’s body (01& 02). Presumably they were able to take advantage of the free meal because the spider was unwilling to release such a large pray item to try to feed on these small interlopers.
We had never seen anything like this gruesome scene before so I contacted Mick Blythe to see if he knew anything about the flies and their behaviour. He commented that “the little acalyptrates don't show enough detail to identify them, but judging by their behaviour they are likely to be Jackal Flies (Milichiidae). These have the habit of lurking about large predators such as spiders, predaceous bugs or mantids, and when the predator makes a kill they join in to share the prey. They have been shown to mop up fluids from the dead or dying insect. We have about 18 species of Milichiidae in this country, though probably not all of them behave as Jackal Flies”.
01. Jackal flies feasting. Gary Farmer