Shape-shifting bug

Hopper adult and nymph
Leaf-hopper (Flatidae) adult and nymph

This picture could well have appeared in my gallery of microfauna a few days ago but I thought it deserved a little more prominence.

What do we have? Two insects on a plant stem, obviously. Two completely unrelated insects, most of us would think – like a man and his dog leaning against opposite sides of a lamp-post, for instance – but we would be wrong: they are the same species. The one on the right is a juvenile – a nymph – of the larger winged insect on the left.

They are Hemiptera – ‘true bugs’. The adults are known as leaf-hoppers or plant-hoppers and these two are probably Colgar rufostigmatum or Colgaroides acuminata in the family Flatidae. The nymphs, as far as I can tell, are not known as anything at all. They are only about 5mm long without the peculiar tail of waxy filaments and are easily overlooked. The adults are more visible, at 8mm or so, but can easily be mistaken for a spine or new leaf on the stem of the plant. Like many Hemiptera, they feed exclusively on sap they suck from the plant.

Insects of many families undergo radical transformations during their life cycle, of course. The caterpillar-pupa-butterfly sequence is well known (but still amazing); cicadas spend their long childhood underground, eating roots, and dig their way out to split open and take wing; dragonflies spend their infancy as ugly aquatic predators before climbing out and emerging as adults; and so on. By comparison mammals (like us) are boring  …  just about all we do is get bigger.

Wasp and leaf-hopper

Black wasp on the ground
Black wasp, just landed

This wasp landed on the paver near a large plant pot and sat there buzzing its wings for a moment, as shown here, and then crawled to a drainage hole in its base and walked inside:

Wasp crawling into the base of a large flower pot
Crawling into the base of the pot (how does it keep its wings clean, I wonder?)

A week or two back, I saw a similar wasp carry prey to a hole in the top surface of the dirt. Together with the one entering the bottom of the pot, it had me wondering whether the whole pot was tunnelled and whether the roots of the plant (actually the Desert Rose which the Sunbird was raiding for nesting material) were being eaten by wasp larvae. The answer to the second question should, I realised, be ‘no’: bugs which carry other bugs home as food were not likely to be root-eaters.

Wasp in flight with prey
Carrying prey towards her nesting site

Here we go again … carrying a leafhopper towards the drainage hole in the bottom of the plant pot. What she didn’t know was that we had re-potted the plant, because it had been looking sickly, since she dug a tunnel there. In the process we saw quite a lot of white Leaf-hoppers in the dirt (maybe a dozen) but no network of tunnels, no colony of wasps and no root-eating grubs.

Finally, here she is trying to re-dig her tunnel while still holding the prey. It didn’t work very well and she flew off again with her load. I saw her fly to a nearby plant and stop for a rest but didn’t see what happened after that.

Wasp trying to tunnel into the pot with a leaf-hopper between her back legs.
Now, where's my hole?

One of the experts on the Flickr Field Guide to Australian Insects kindly identified the wasp for me as ‘a Gorytini wasp, perhaps Austrogorytes sp., Crabronidae’. All Crabronidae are solitary wasps which provision nests with paralysed prey as food for their larvae. The biggest of them take cicadas – they must be a lot bigger than my wasp here which is only about 10 mm long and preys (exclusively, going by what we saw in the dirt) on Flatid leaf-hoppers like these.