Overview
Adults feed on nectar or honeydew, or at extrafloral nectaries, while females prey on and provision their nests with a range of insect groups as well as spiders (Araneae). Nesting behaviour is variable: they often nest in pre-existing cavities or in twigs; many are ground nesters; and some construct tubular mud nests. Communal nesting has been recorded for several subfamilies. The female stings and paralyses her prey which she places in cells inside the nest where an egg is then laid in each cell; the developing larva feeds on the paralysed prey. Different subfamilies display specific prey preferences. Pempredonidae prey mostly on Hemiptera (bugs) and Thysanoptera (thrips), Crabroninae are mostly predators of Diptera (flies); Philanthroninae prey on small adult Coleoptera (beetles); Larrinae, the largest subfamily in Australasia, prey mostly on Orthoptera (crickets and grasshoppers) as well as preying mantids, Blattodea (cockroaches) and spiders; while Nyssoninae have a broad prey range including Hemiptera, Diptera, Hymenoptera, Neuroptera and Odonata. The biology and systematics of the Australian nyssonine genus
Bembix
(sand wasps), with more than 80 species, has been examined in detail.
Description
Crabronids can be recognised by the lack of a petiole between the mesosoma and metasoma or, if a petiole is present, then it is short or composed of tergal and sternal components and the basal jugal lobe of the hind wing is small. Of the nine subfamilies, five are represented in Australasia; Crabroninae, Larrinae, Nyssoninae, Pemphredoninae and Philanthinae, and these can be identified using Bohart and Menke (1976) and Naumann (1991). Some crabronids can be mistaken for bees, but they lack the plumose hairs.
Distribution
This is a relatively new family that was created from dividing the Sphecidae
sensu lato
of previous authors (e.g. Bohart & Menke 1976; Naumann 1991) into two families, Sphecidae
sensu stricto
and Crabronidae, on phylogenetic grounds (see Melo 1999). It comprises all of the subfamilies previously contained within Sphecidae
s.l
. except for Sphecinae (now Sphecidae
s.str.
) and Ampulicicinae (now a separate family Ampulicidae). The family comprises the majority of species previously in Sphecidae
s.l
. with about 430 species described for Australia, and 18 for New Zealand. There are also a large number of species in New Guinea and throughout the south-west Pacific.
Further information about the Crabronidae can be found in Bohart & Menke 1976, Finnamore & Michener 1993, Harris 1994, Melo 1999 and Naumann 1991.