Small-headed hump-backed spider flies are a nightmare – if you are a spider!

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!

11 Replies to “Small-headed hump-backed spider flies are a nightmare – if you are a spider!”

  1. A great story! What drama is happening all around us and most of us unaware. Thank you.
    I’m a bit of a spiderphobe myself (just huntsmen really) so I rather like these spider flies. Are there predators which eat or parasitise them in turn?

  2. Denis
    Fantastic research to get the answers.
    Have seen them on my clothe line, hanging underneath.


  3. So many insects require very good human vision! Amazin how so much research goes into such tiny creatures.

  4. I have them in abundance on my property, on my electric fences, gates and especially my clothes line is where they really enjoy laying their eggs. Is there any way of discouraging them from a particular location, like my clothes line so I don’t have to wipe it down every time I want to use it?

    • Hi Meaghan. Sorry I missed this comment but I did reply on FB.
      I don’t know of any way to deter them

  5. For decades we have wondered about the strange , black, rough material that regularly appeared on fence wires on our property at Freshwater Ck Vic. This season I found the source – flies I identified as Ogcodes sp. via iNaturalist. In late October ’23 there were clusters of males and females mating and laying on fence wires. Also found them on tall grass stalks. Thankyou for the life history info. LOTS of wolf spiders et al here.
    Saw same thing today on a nearby property.