Ectemnius, Williamsita, Lestica (CRABRONINAE: Crabronini)
[cover photo by Victor Fazio III, iNaturalist sighting #2766060. CC 4.0 BY-NC-ND]
Workbook
This page compares the Australian species from three genera of the tribe Crabronini: Ectemnius, Williamsita, and Lestica. The differences between genera are so subtle that one really needs to go down to the species level.
In particular, Australian species of Ectemnius and Williamsita can look very alike. And the history of their names illustrates their collective attributes (see table, below). For example, Turner (1912, 1915) included the ten species known at that time within a common sub-genus, Crabro (Solenius).
Leclercq revised these species in several papers during the 1950s, dividing them across two genera and describing two new species.
Subsequently Leclercq abandoned sub-genera (1974, 1999) and compiled a key to the Williamsita (1974) … but stressed that the work was of a preliminary nature.
Key to Williamsita females (Leclercq 1974). Click to open/download as pdf (380kb)
There have been no revisions published since Leclercq’s work. However, iNaturalist is providing a growing body of data so we can now test Leclercq’s descriptors against a larger sample. I suspect that the collection of sightings on iNaturalist contains much valuable information … and probably the only published images of some of these species. Trying to put an accurate ID to them seems a worthwhile pursuit – and an enjoyable project too.
Fortunately for my purposes, the total number of described species across the three genera is manageable. I have trawled the works of Smith, Turner, and (of course!) Leclercq in an attempt to find characters that might enable identification of these wasps from photos.
In another stroke of good luck for me, colouration proves to be an important (and very helpful!) diagnostic. Unlike many fine structural features, the shape, colour and location of body markings are often visible –even in field photos, and despite the rather small size of these wasps.
I will continue to tweak these summary tables as I work through the iNaturalist images. Some of the descriptions are a bit ambiguous, as different authors use different language and terminology, and often emphasise different features. For some species, descriptions are available for just one sex … and sometimes are based on a single individual. I realise that many of the fine details listed will rarely be visible but I include them in the full table, just in case.
Bits & Pieces
A mixed collection of diagrams and text from the source literature, plus the few verified images I’ve found online.
References
Bohart, R.M. & Menke, A.S. 1976. Sphecid Wasps of the World: A generic revision. University of California Press, Berkeley.
Leclercq, J. 1950. Sur les Crabroniens orientaux et australiens rangés par R.E. Turner (1912-1915) dans le genre Crabro (subgenus Solenius). Bulletin & annales de la Société entomologique de Belgique 86: 191-198
Leclercq, J. 1951. Sur trois espèces de Lestica (Solenius) (Hym., Sphecidae, Crabroninae). Bulletin et Annales de la Société Royale Belgique d'Entomologie 87: 169-173
Leclercq, J. 1954. Monographie Systématique, Phylogénétique et Zoogéographique des Hyménoptères Crabroniens. Liège : Lejeunia Press 371 pp.
Leclercq, J. 1974. Crabroniens d'Australie (Hymenoptera Sphecidae and Crabroninae). Bulletin et Annales de la Société Royale Belgique d'Entomologie 110: 37-57
Leclercq, J. 1999. Hyménoptères Sphécides Crabroniens du genre Ectemnius Dahlbom, 1845. Espèces d'Asie et d'Océanie et groupes d'espèces de la faune mondiale. Notes Fauniques de Gembloux 36: 3-83
Maynard, D. & Fearn, S. 2021. Ecological and behavioural observations of a nesting aggregation of the endemic Tasmanian digger wasp Williamsita tasmanica (Smith, 1856) (Hymenoptera: Crabronidae: Crabroninae). Papers and Proceedings of the Royal Society of Tasmania 155(1): 43-50
Pate, V.S.L. 1947. On Williamsita, a new genus of wasps from New Caledonia (Hymenoptera, Sphecidae, Pemphilidini). Proceedings of the Entomological Society of Washington 49: 107–112
Smith, F. 1868. Descriptions of aculeate Hymenoptera from Australia. Transactions of the Entomological Society of London 1868: 231-258
Turner, R.E. 1908. Notes on the Australian fossorial wasps of the family Sphegidae, with descriptions of new species. Proceedings of the Zoological Society of London 1908: 457-535 pl. xxvi
Turner, R.E. 1915. Notes on fossorial Hymenoptera. XV. New Australian Crabronidae. Annals and Magazine of Natural History 8(15): 62-96
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.