Australian garden insects with Denis Crawford
Most people are familiar with spider hunting wasps, but have you ever heard of flies that kill spiders?
All known species of flies in the family Acroceridae – otherwise known as ‘spider flies’ – are internal parasites of spiders. In other words, their larvae feed inside spiders.
It’s how the larvae manage to get inside the spider that makes this story interesting. Let me know if you like the video!
Insects that are armed with powerful stings are often strikingly coloured to warn off potential predators – a strategy known as aposematism . A good example of this is the black and yellow colour pattern of the European wasp (Vespula germanica).
Some harmless insects take on the appearance of aposematic insects even though they are not actually dangerous themselves. Hover flies are an example of this. One common hover fly species – the drone fly Eristalis tenax – is an excellent bee mimic, and was the star in a recent ‘one minute bugs’ video (link).
Other common hover flies (image below) are harmless flower visitors but their striking yellow and black markings superficially resemble the markings of bees or wasps. Bees and wasps usually have stings and consequently are left alone by many predators. Hover flies don’t have stings, so by adopting colour patterns similar to bees and wasps this affords the hover flies some protection. This defence strategy is known as Batesian mimicry.
You would think that a spider as robust (and venomous) as a huntsman spider (Sparassidae) would be pretty safe from predatory and parasitic insects. But not so. This article is the first in a series on the insects which make a meal of large spiders.
A few years ago I witnessed a titanic struggle taking place on a window at the front of our house. A large spider hunting wasp (or ‘spider wasp’) was pulling a huntsman spider backwards up the window glass.
