Family Pompilidae (Spider Wasps)

Spider wasps are distinctive in their habit of quick movement on the ground and with rapid wing flicking. Often they are seen around, or in the act of digging, a burrow in sandy soils. Their displays of high activity correlates strongly with bright periods during warm days. Adult spider wasps may feed on nectar but their larvae are parasites on spiders provisioned by their mother. Typically an adult female will seek and attack a single spider, usually much larger than themselves, for each of her offspring. As soon as the wasp discovers a suitable host she rapidly attaches herself very close to the spider’s body, usually at the base of a leg. This position makes it impossible for the spider to successfully strike its fangs. The spider is paralysed with a sting to its venter and dragged to a suitable retreat. An egg is then laid on the paralysed spider and the larva gain nourishment from it while it is still alive. The vital organs of the spider are left until last to avoid rotting. This scenario is typical though the strategies of adult female Pompilids are diverse.

Tasmania currently has 27 described pompilid species in 10 genera. The bulk of these belong in Pepsinae, with Ctenocerinae (Epipompilini) and Pompilinae each represented by 6 species. Sphictostethus (Pepsinae: Pepsini) and Epipompilus (Ctenocerinae) are most speciose with 6 species each, and together they contain 8 of the 10 species only found in Tasmania. The pepsines, Calopompilus auropilosellus and Xenocurgus tasmanicus, are the two other endemics.

Subfamily Ctenocerinae

Tribe Epipompilini
All wasps in this (now defunct) tribe are placed in Epipompilus. They have a rather depressed form, shorter than usual legs, head generally held more horizontal, and often eyes finely haired. Females normally with noticeably thickened fore femur and males with antennae crenulate when viewed from the side. Epipompilus species are considered primitive in their behaviour, attacking spiders in their own retreats such as under bark. Usually a female with an egg sac is located and both spider and eggs will be devoured by the larva

Subfamily Pepsinae

Tribe Pepsini
Both sexes in this (now defunct) tribe have the second ventral segment of the metasoma (abdomen) marked by a transverse groove or emargination. The females often have hind tibiae noticeably serrate or toothed dorsally.

 

Tribe Psoropemulini
This tribe contains only Psoropempula, a genus of mutillid-mimics. The head and thorax above are covered with tightly packed coarse punctures. The spines at the apex of hind tibiae are of Pompilinae form, ie irregular in length and splayed, however other characters of Pompilinae as listed in the respective section below do not occur. Psoropempula are likely cleptoparasites of other pompilids. Presumably the females locate other recently provisioned nests. The egg of the original provider is destroyed allowing their own larva to consume the stolen host without competition.

Genus Psoropempula

  . 

Subfamily Pompilinae

Genus Ctenostegus

 

Genus Turneromyia

      

Subfamily Ceropalinae

(Currently empty)

Pending ID – Pompilidae

    

References

Evans, H. E. 1975. A review of Psoropempula, a new genus of Australian Pompilidae (Hymenoptera). Transactions of the Royal Entomological Society of London 126(3): 261–278.

Evans, H. E. 1976. A revision of spider wasps of the genus Ctenostegus (Hymenoptera, Pompilidae). Australian Journal of Zoology Supplementary Series 43: 1–107.

Evans, H. E. 1984. A revision of the spider wasps of the genus Turneromyia (Hymenoptera, Pompilidae). Australian Journal of Zoology Supplementary Series 101: 1–59.

Naumann, I. D. 1991. Hymenoptera (wasps, bees, ants, sawflies). In: The Insects of Australia Volume II. 2nd edn. Brown Prior Anderson Pty Ltd, Burwood, Victoria.

Townes, H. 1957. Nearctic wasps of the subfamily Pepsinae and Ceropalinae. Bulletin of the United States National Museum 209: 1-286.

Wikipedia 2012, ‘Spider wasp’, wiki article, May 7, accessed 27 May 2012, <http://en.wikipedia.org/wiki/Spider_wasp>.Zborowski, P & Storey, R 2010, A Field Guide to Insects In Australia, 3rd edn, Reed New Holland, Australia.