03 May 2012

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).