Workbook

These distinctive crabronids are a regular summer sight here in the forest, but this year their numbers seem even higher than usual. Reason enough to take a closer look at the genus … and to finally put a species names to our local representatives: Sphodrotes punctuosa

Uncommon & little-known wasps

Sphodrotes appear to be relatively rare wasps. For example, there are currently only 42 recognised sightings of Sphodrotes on iNaturalist – and 12 of those are mine.

Also, most museum holdings are relatively small. For example:

• 7 in the Australian Museum, all S. ordinaria from NSW

• 15 in the Queensland Museum, all S. ordinaria from QLD with the exception of 1 S. marginalis (collected in 1913)

• just 1 in the Melbourne Museum, S. punctuosa (collected in 1914)

The Tasmanian Museum is one exception, with many collections from that state added in recent years bringing their records of Sphodrotes to 53. All are simply listed as ‘Sphodrotes’, but they are likely to be S. punctuosa, as that is the only species known from Tasmania (at least, at the time of Lomholdt’s paper).

The only published paper dealing with their biology is the work of Howard E. Evans which describes the nesting behaviour of S. nemoralis in Far North Queensland (Evans 1973).

A bit about behaviour

Our local Sphodrotes make their seasonal debut in mid-late November. Soon thereafter males become a common sight, patrolling the forest tracks in earnest. Each attempts to claim a small patch of ground, clearly on the lookout for females while chasing off intruders of all kinds … even butterflies.

Females choose concealed spots to dig their nests, typically under fallen leaves. Once the burrow is constructed the females become difficult to spot. When returning with prey, they typically disappear from sight in seconds. Although occasionally they will perch or land nearby and, if I’m quick enough, I get a look at their cargo.

And if I’m very (very!) lucky, I get to see a mating. It’s a quick affair. The male grabs hold of the female, there’s a quick tussle, and they separate. The male then goes back to patrolling while the female heads underground. I have witnessed this on several occasions but rarely managed to get my camera onto them in time. Last week I was quick enough to catch the action … just! The details are revealing.

Genus identification

Sphodrotes are distinctive wasps and are generally quite recognisable from field photos that show some or all of the following characters: head shape & texture, including eye shape & ocelli; forewing venation; texture of the thorax; shape of the abdomen/gaster.

For the full list of characters, and to compare Sphodrotes to other members of the subfamily (Crabroninae) and tribe (Miscophini), refer to the relevant notes pages:

Species identification

The genus Sphodrotes is endemic to Australia. There are currently only 12 described species … and before the work of Lomholdt (1983) there were just five.

Based on Lomholdt’s work, I’ve summarised the features that distinguish between species. As usual, I’ve emphasised characters that might be visible in field photos.

It is worth noting Lomholdt’s assertions regarding geographic limits (Lomholdt 1983).

“Most species are restricted to relatively small geographic areas. Only rubricata and ordinaria display very extensive distributions. As judged from the available material, Sphodrotes species are rare.” (p. 87)

“Female punctuosa might be misidentified as occidentalis, but the distribution areas of the two are widely separated, punctuosa occupying SE Australia incl. Tasmania, while occidentalis occurs in SW Australia.” (p. 114)

Location is, therefore, an important element distinguishing between some species … yet with so few specimens in collection, the true range of some species must remain an open question. Perhaps, in time, iNaturalist sightings will provide further insights.

Sphodrotes punctuosa

With three specimens of our local species in hand, I can take a close look at the various characters used to distinguish between species. Of particular importance are the body colour and pilosity, facial texture, shape of the propodeum, and clypeus shape.

Our local species agrees with descriptions of Sphodrotes punctuosa. In particular:

• S. punctuosa is the only species listed for our region. The widespread species S. ordinaria is a similarly coloured wasp, but it hasn’t been recorded south of Sydney. Importantly, however, I’m not relying on location alone to exclude this east coast species.

• S. punctuosa and S. ordinaria have distinctly different shape to the propodeum (see species summary table above for description of S. ordinaria).

• S. occidentalis is a similar looking wasp. Black gaster, black femora, strong punctation. However, Lomholdt (1983) emphasises the large genae and strongly raised occipital carina of S. cygnorum … and so by extension, S. occidentalis. The author also explicitly differentiates these two species on the basis of their highly disparate locations. Good enough for me!

As a further test, I have compared the full description of S. punctuosa with my three specimens. For each of the characters that I’m able to image, they match. The relevant excerpts from Lomholdt’s (1983) description of S. punctuosa (pp 98, 101) are included in the gallery below (in italics).

A closer look at the clypeus

The shape of the clypeus is reasonably consistent across the genus.

Sphodrotes genus description (Lomholdt 1983):
“Female clypeal synsclerite (i.e. clypeus + lateroclypeus) with a wide median, slightly arcuately convex lobe usually slightly emarginate medially, three small rounded lateral teeth or nodules usually present. Median lobe and lateral teeth are strongly reduced in males.” p. 86

However, there are differences between species as highlighted by the various figures in Lomholdt’s paper. As far as I can discern, my specimens are a good match for Sphodrotes punctuosa.

Bits & pieces

Specimen details
- 2301G: female collected 20th Jan, 2023
- 2301L: female collected 24th Jan, 2023
- 2501A: male collected 2nd Jan, 2025

References

Bohart, R.M. & Menke, A.S. 1976. Sphecid Wasps of the World: A generic revision. University of California Press, Berkeley.

Evans, H.E. 1973. Observations on the nests and prey of Sphodrotes nemoralis sp.n. (Hymenoptera: Sphecidae). Journal of the Australian Entomological Society 12: 311-314 … freely available via link on Wikispecies page

Kohl, F.F. 1889. Neue Gattungen aus der Hymenopteren-Familie der Sphegiden. Annalen des Naturhistorischen Museums in Wien 4: 188-196

Lomholdt, O. 1983. A revision of Sphodrotes Kohl, 1889 (Hymenoptera, Sphecoidea, Larridae). Steenstrupia 9: 85-116 … freely available via link on Wikispecies page

Turner, R.E. 1910. Additions to our knowledge of the fossorial wasps of Australia. Proceedings of the Zoological Society of London 1910: 253-356

Turner, R.E. 1914. Notes on fossorial Hymenoptera. XIII. A revision of the Paranyssoninae. Annals and Magazine of Natural History 8 14: 337-359

This is a workbook page … a part of our website where we record the observations and references used in making species identifications. The notes will not necessarily be complete. They are a record for our own use, but we are happy to share this information with others.