Ectemnius solitary wasp targets solitary bee
I quite often see Ectemnius solitary wasps in my garden. They do have noticeable large fang-like mandibles and large eyes. There are several different species and like all wasps, they are predators. Especially of several fly species including hoverflies and as you will see the film, it will tackle solitary bees! Most species nest within dead or rotten wood such as tree stumps, logs, wooden fence posts. They are capable of burrowing into soft decaying wood and will use existing burrows of other insects, or in this case my nest boxes! So studying them, what they catch etc., will be so much easier than having to cut open rotten logs to see what is inside!
The predatory Ectemnius solitary wasp inside my nest box
From my observations, several of these wasps have used my nest boxes over the years to sleep in or rest up during the day. Now I have more nest blocks adapted to them, other solitary wasps and summer bees, I may get lucky and watch them stock the cavities up.
I was fortunate to watch an incident some years ago, it was only when I slowed the film down that I actually noticed what in fact had just happened right in front of my eyes. Of course, it could have been a beewolf (Philanthus triangulum) although the colouring was more blackish with yellow stripes rather than yellow with black stripes and as it is a bee specialist it may have been more successful, so unless told otherwise I will stick with Ectemnius!
In this case, the solitary bee (possibly Andrena similis?) was busy feeding upon lasts years parsnips that I had left to flower as an insect attractant on an allotment site in Garston, Liverpool a few hundred yards from the River Mersey. Initially, I was filming the flowering parsnips which had many other insects foraging on it, including bumblebees and social wasps. This wasp deliberately targets the solitary bee whilst it was feeding. Flying near to it then pouncing onto its rear, it attempted to carry it off, but the bee was too large, eventually flicking the wasp from its back! It is all over in a flash, so watch the video and you will see the attack, the takeaway food to go meal that did n’t want to go! Filmed 25/6/13
A list of Ectemnius wasp species can be found here BWARS
Interesting article “The hoverfly hunting machine” by biologist Dr Africa Gomez
Another solitary wasp article by Dr Isabella Brey “Lone Wolves” which includes Ectemnius wasps.
Excellent photos here by Jeremy Early of Ectemnius wasps
Thanks to Dominic K for the stills used in the film
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