Scientific Name: Family Evaniidae
When and where in yard? : Nov 2018 (late spring) and Mar 2019 (early Autumn) On back wooden fence and swimming in birdbath.
Observations: Two wasps (a mating pair perhaps?) swam around the bird bath and each other as if dancing. I thought at the time that the water was their natural habitat as their long back legs seemed like some sort of water strider and their strange abdomen almost like a sail. After learning that they were wasps and been unable to find any other swimming pictures, I’m not sure what they were doing. I observed hatchet wasps a few more times. A couple of times walking on our wooden paling fence and once on a pumpkin leaf after rain (pictured). The one on the leaf was tiny around 5mm body length – about half size of the bird-bath wasps, so maybe different species.
Fun Facts: The hatchet wasps with their strange flat abdomen and thin waist have attracted a lot of common names, most relating to the way their abdomen moves up and down as they move. They can be called Flag Wasps, Ensign Wasps or Nightshade wasps. They are harmless to humans and the species, Evania appendigaster has a beneficial role in controlling cockroach populations. This hatchet wasp lays its eggs in cockroach egg cases. The wasp larvae hatch quickly and eat the roach eggs. Although, I don’t think any of my observed hatchet wasps are E. appendigaster. Because of their smaller size, irridescent body spots and black eyes (photos I’ve seen of E.appendigaster are blue-eyed). Adult hatchet wasps feed on nectar and honeydew secreted by aphids and scale insects.
The Paper Wasps
Asian Paper Wasp
Scientific name: Polistes chinensis
When and where in yard: Only observed during the three summer months. In the 2018/19 summer this invasive wasp became the most prolific wasp species in my yard – outnumbering Polistes humilis (Wasp header image) – the native paper wasp. This was a turnaround from 2017/2018 in which there were only occasional sightings of the Asian Paper Wasp.
They were seen drinking water from the leaves after rain, gathering nectar from flowers, scouting for prey on leaves and scraping the wood (for nest material) from garden stakes. I looked everywhere in the backyard for a nest. Then one day my husband looked up as we came up the front drive, spotting a big nest under a peak in our roof. A perfect sheltered spot.
Observation: Even though these wasps were prolific in my garden (2018/19) they didn’t act aggressively even when I was quite close. The nest was up high, above the garage, so I had no reason to test their reaction when I approached their nest. The nest was large – around 20 cm across. I believe they out-competed other wasps in my garden particularly other paper wasps. The Common Paper Wasp (native) numbers were significantly reduced during and Ropaldia sp weren’t observed at all in the 2018/19 year. The nest was removed late in February. I decided eventually to have a pest controller do the job as I wasn’t keen on standing on a ladder while spraying potentially angry wasps and my husband was incapacitated after knee op. *After removal of the nest there was an immediate drop in the population and the Common Paper wasp once again became the most prolific paper wasp in both front and back gardens.
Fun Facts (or not so fun) : P. Chinesis (Asian Paper Wasp) is very similar to another invasive paper wasp, P. dominula (European Paper Wasp). The best way to tell the difference is the Asian Paper Wasp lacks spots on top of the thorax (see below). Both these species should not be confused with the highly aggressive (to humans and other insect species) European Wasp (or German wasp) sometimes called yellow-jackets. It is also black-and-yellow-striped but is more like a bee in shape and has black antennae. The papery bag-like nests of the European/German wasp (Vespula germanica ) tend to be hidden underground or in wall cavities. V. germanica is more likely to come in contact with humans as they are scavengers, attracted to pet and human food. All three wasps mentioned are non-native and have become widespread in Australia. But I especially don’t want to see Vespula germanica in my garden.
Common or Native Paper Wasp
Scientific name : Polistes humilis
Where and when in yard : I observed Native Paper Wasps right from early spring (Sept) through to the end of autumn (May). This wasp has very similar habits to the European paper wasp (above). P. humilis is a good photographic subject taking time to rest on leaves and feed on nectar from variety of flowers. Also observed on garden stakes gnawing wood to combine with their saliva to make the ‘paper’ for the nest. A favourite plant was the Grevillea ‘Orange Marmalade’ (Wasp header image). I’ve observed several nests over the years, under garden furniture, attached to branches and under eaves.
Observations: Polistes humilis has a shorter body than Polistes Chinesis (Asian Paper Wasp) and red-brown, as well as yellow markings. The common paper wasp has never shown any aggression toward me even when I took some time to stand directly under a large nest (about 9cm diameter) in order to photograph. This nest (see below) was built under eaves on an outdoor light fitting (2017/18) another nest of similar size (2018/19) was seen nestled under eaves of a metal garden shed . The nests hung with hexagonal cells facing down, held with a single ‘stalk’. The two larger nests were at times rather crowded with with 25-30 wasps in attendance. Apparently the native paper wasp can re-use nests (Wikipedia) however the nest on the light fitting was not re-occupied the subsequent summer (18/19) – although you have to admire the strength of the construction as it is still largely intact. Generally my policy with native paper wasps is to leave them be, BUT I do understand if people choose to remove them particular if they are in a thoroughfare or a place where you might accidentally disturb their nest – such as under a garden chair – I did remove that particular nest as I didn’t fancy a sting on the rear end.
Fun Facts: It is hard to confine myself to just a few facts about paper wasps as they are expert builders with fascinating social structures. But there is much written online about this so I’ll just relate my facts to the picture below. The photo of the nest shows different stages of wasp growth. 1.The open cells with oval shaped eggs (look closely) laid by one of the queens (dominant females). 2. The eggs grow into the white larval grubs – seen in the shiny cells. These are fed on mashed-up caterpillars and other insects hunted by the adult wasps. 3. The larvae spin their own silken cap (white-covered cells) and pupate before emerging as adult wasps.
Small Brown (white-faced*) Paper Wasp
Scientific name : Ropalidia plebeiana
*Note on Common name: The ‘white-faced’ in the common name I find misleading. The R.plebeiana I photographed didn’t have obvious white faces or even, what many observers call, ‘cream.’ For me, a more useful term would have been the Southern Small Brown Paper Wasp as R. plebeiana is reportedly the only temperate Ropalidia species ie the only Ropalidia in my region. Although this description may not be useful for someone living in southern or highland Queensland where several Ropalidia sp can co-exist.
Where in yard : I only saw these wasps in May/June 2017. They were only observed on the Grevillea ‘Orange Marmalade’ which grew against the back fence until strong winds blew it down in August 2017.
Observations : On a quick glance these wasps may be confused with Common Paper Wasps. However they are smaller (as the name infers) and have a distinctive ball-like waist with a narrow pale band. They were photographed on the long leaves and bright flowers of the orange grevillea.
I haven’t seen any nests of the Southern Small Brown Paper Wasps. They were observed in late Autumn and early Winter which seemed a rather cold time for them to make an appearance. However I learned that they have a significant population in the more southerly, inland city of Canberra (much colder) so these wasps are obviously resistant to quite low temperatures, unlike their more northerly Ropalida sp relations which prefer warmer climes.
Fun facts: Small Brown Paper Wasps do not build neat symmetrical nests like the Polistes wasps. Their nests have open cells like Polistes sp but can sprawl vertically or horizontal – often in a very sheltered position, such as under a bridges, porches or rock overhangs. Nests with different foundresses (founding queens) can be built side by side to form large aggregations of colonies. Also the practice of nest-splitting has been observed (Comb cutting in Ropalidia plebeiana). This is where egg-laying females take over different parts of the nest and eventually gnaw a division in the comb to form two separate colonies. Large aggregations do not seem to occur in the extremes of of the wasp’s range ie north (Queensland) or south (Canberra) but are common in coastal NSW. R. plebeiana is generally non-aggressive and reportedly it’s sting not as painful as the larger paper wasps.