Robber ambushed

[Not for the faint of heart]

A tiny war was fought in my yard this morning. While deadheading my flowers, I found a fierce battle underway, between a Jagged Ambush Bug, Phymata sp., (right), and a Friendly Robber Fly, Efferia aestuans:


Both were alive and moving, but the ambush bug had the upper hand, and its pale green proboscis was sunk into the robber fly:


I went away for half an hour, and when I came back the ambush bug was alone:

Jagged Ambush Bugs

I searched for the robber fly, and found it lying intact but motionless on a lower leaf:

Friendly Robber Fly, Efferia aestuans

It may or may not have been alive, but it was certainly paralyzed: ambush bugs inject a paralyzing poison through their proboscis, and then eat their prey at leisure. This ambush bug had foolishly allowed its prey to slide out of its formidable grip, uneaten.

Ambush bugs are so-named because they lie in wait, extremely well-camouflaged, until woe betide the unwary bug that wanders too close:


Below is the same one in close-up, carefully positioned on the yellowy-black centre of the flower where it is almost invisible:


The biblical phrase “they lay in ambush” fits its posture perfectly, and makes me realize why “sit in ambush” or “stand in ambush” just don’t cover it.

Appendix: Extra detail for those other obsessives like me:

Wikipedia says Robber Flies  “..have three simple eyes (ocelli) in a characteristic depression on the top of their head between their two large compound eyes. They also have a usually dense moustache of stiff bristles on the face; this is called the mystax, a term derived from the Greek mystakos meaning “moustache” or “upper lip”. The mystax has been suggested to afford some protection for the head and face when the flies deal with struggling prey” . You can see one of the simple eyes pretty clearly in the closeup below, and also the bristly mystax (today’s new word.)

Friendly Robber Fly, Efferia aestuans

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