Insect antennae V.

This blog is dedicated to Andreas Kay (1963–2019), a remarkable biologist and natural history photographer, some of whose photographs I have included below. I never met Andreas, but like many people, I followed him on Facebook and marvelled at his photographs documenting the diversity of life in Ecuador.  He generously shared over 28,000 of his photos on his websites: Ecuador Megadiverso ( and YouTube (

Here are a couple of his fabulous images, of the Emerald cockroach wasp, with a remarkably back story!

Emerald cockroach wasp or jewel wasp, Ampulex sp., Ampulicidae by Andreas Kay (Flickr CC BY-NC-SA 2.0)

Emerald cockroach wasp (Ampulex compressa)

When the wasp encounters an American cockroach, Periplaneta americana (Linnaeus) it delivers two stings. The first is a swift sting into the thorax which causes a transient paralysis of the front legs; the second sting is made into the head cavity, targeting both the subesophageal ganglion and brain (Arvidson et al., 2018). Stinging the head ganglia in this way causes behavioural changes in the cockroach rendering it  passive and submissive to manipulation by the wasp.  The wasp then clips off the cockroaches’ antennae ‘with buzzsaw actions of its mandibles’ and drinks its hemolymph, ‘using the antennal stumps as straws'(Arvidson et al., 2018)! The wasp then leads the stung cockroach by its truncated antennae into the wasp’s burrow, where it proceeds to lay an egg on it! It effect, it turns it into a ‘zombie’ cockroach; ‘a complacent, living source of nourishment for the single offspring’. It does not get much more gruesome than that, does it?!

Cockroach Wasp, Ampulex sp. by Andrea Kay Flickr (CC BY-NC-SA 2.0)

I have not posted many images of dipteran antennae in this series, apart from the remarkable Drosophila antennae in Insect Antennae I. Fly antennae are no doubt fit for purpose, but they are fairly small and stubby compared to a lot of other insects! The thin and sensitive arista is a nice feature though, and helps them sense changes in temperature and humidity; probably more (see below).

Yellow jacket hover fly (Milesia crabroniformis) Galicia, Spain. Photo by Raymond JC Cannon

Stilt-legged flies (Micropezidae, Taeniapterinae) like the one shown below photographed by Andrea’s Kay, have a habit of standing motionless while waving their prominently marked front legs in front of their heads, a behaviour which is generally thought to be their mimicry of wasps. But are they mimicking wasps or displaying their lovely legs, or both? I think they use them for signalling, as shown here in this video. But perhaps they also fool a few other creatures into thinking they are wasps?

Stilt-legged Fly, Poecilotylus sp., Taeniapterinae by Andreas Kay (Flickr CC BY-NC-SA 2.0)
Stilt-legged Flies (Micropezidae) mating, Sarawak, Malaysia, photo by Bernard Dupont (Flickr CC BY-SA 2.0)

Here’s a fabulous video of one using its lovely legs/would be antennae to clean itself! The Ichneumon Wasp, Nonnus sp., shown below, has some lovely, genuine antennae, with white segments not unlike the legs of the stilt-legged flies above? Why do the wasps have these white segments? Is it for signalling as well?

Ichneumon Wasp, Nonnus sp. Ichneumonidae by Andreas Kay (Flickr CC BY-NC-SA 2.0)

I also posted a photo of another ichneumon wasp, very much like the one above (but I am no taxonomist!) , in Insect Antennae. III).


I think I have written enough about insect antennae now, although the subject is enormous and would make an interesting book, especially with some of the wonderful photographs taken by Andreas Kay.


Arvidson, R., Landa, V., Frankenberg, S., & Adams, M. E. (2018). Life History of the Emerald Jewel Wasp Ampulex compressa. Journal of Hymenoptera Research63, 1.

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