Flower Wasp - Tiphiidae - Thynninae spp.

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Flower Wasp - Tiphiidae - Thynninae spp. 

There are many Flower Wasps with the above commonly known as Black or Brown Flower Wasps and although not as spectacular as many others, play an important environmental role by being the sole pollinating agents of many orchid species.

They are very common and large numbers can at times be seen feeding on flowering plants; they vary in size from 3 to over 35 mm (to 11/2”) in length, although most local species are between 1- 2 cm (3/8”- 3/4”) long. Only the males have wings and carry around the smaller female to mate and provide her with food. She has no wings, but that feature permits her to dig in the ground in search of scarab beetle larvae, of which she parasitises by stinging to immobilise and to lay her own egg onto it. 

 When the female has finished and is ready to be carried off, she will release pheromones to attract a male. Many orchids have copied these pheromones to attract the males, who whilst trying to carry off the female (actually the orchids labellum), will pollinate the orchid (example). 

The Thynninae wasps also pollinate a large variety of plants in a more normal fashion by transferring the pollen whilst feeding on plant nectar. One wasp shown above has the Leek Orchid’s (Prasophyllum) pollen packets (pollinia) that have become attached to its head and ready to be deposited on other flowers. In other situations, pollen becomes attached to the hairs on their head and bodies, so transported around that way. Their hair arrangement is similar to the Hairy Flower Wasps (Scoliidae), but are without their bright coloration and wing pseudovenation (see here).

Hairy Flower Wasp – Scoliidae – Campsomeris sp.

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Hairy Flower Wasp – Scoliidae – Campsomeris sp.

Most Hairy Flower Wasps are black or blue/black, but the Campsomeris genus have orange, yellow or gold markings and generally are amongst the largest of wasps with the above species being 3-4 cm (1.5”) in head/body length. They are solitary insects without a nest, as the female lays a single egg on a paralysed and insensitised (stung) scarab beetle larvae, leaving it to hatch and consume the host. Because these wasps have no nest to protect and fortunately for people are not aggressive and will only sting if physically interfered with.

Both males and females of this family are winged, but can differ considerably in other ways; with Campsomeris the males are similar but slimmer and have longer antennae (the above wasp is female). The female will dig into the ground in search of scarab larvae, including mown lawns so can be found around human habitation. Males on the other hand will often fly close to the ground waiting for the females to emerge, which will indicate wasps are active in the immediate area.

With all the digging and flying activity, these wasps need the energy of sugars found in flower nectar and can be encountered with their head buried amongst the blossom. Locally, the individual Melaleuca subfalcata flowers are favoured, which also attract other flower wasps. 

To distinguish Hairy Flower Wasps (Scoliidae) from other wasps (including other flower wasps) that may also be hairy, features like the general shape of the insect, antennae (number of segments) and the eye (kidney shaped) are important. However the most distinctive is the venation of the (yellow) wings, particularly the fine parallel pseudovenation (grooves) near the wing tips (see photo above). These wasps are widespread and most active during warmer months.

Flower Wasp - Tiphiidae - Hemithynnus sp.

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Flower Wasp - Tiphiidae - Hemithynnus sp.

Wasps in the Tiphiidae family are generally known as Flower Wasps as the adults feed on the nectar of various flowers. It is a large family that is represented in Australia by 3 sub-families, two of which both the male and female wasps have wings, but in the third Thynninae, the female is wingless and is carried about or otherwise feed by the much larger winged male.

The male thynnine wasps are attracted to the females when she releases a pheromone to indicate she is ready to mate. It is interesting to note that many plants, particularly orchids mimic this pheromone to attract the male wasp, who inadvertently pollinates them when they grasp the labellum, which they think is the female. However most of these wasps would be much smaller than this species (probably a Hemithynnus sp.) that is over 3 cm (11/4”) in length (excluding antennae), so a little large for most orchid flowers. The wingless female above (which may not be the same species) is about a third the size of the male.

These wasps are parasitic on the larvae of burrowing scarab beetles, whereby after mating the wingless female digs into the soil to locate them and will then lay at least one egg on each. They must encounter a number, as they are reasonably common in the Esperance (near coastal) sandy heath from November to January.