Black flower wasps are useful native wasps.

An interesting native wasp: black flower wasp

Black flower wasps are large, solitary, native wasps with iridescent blue wings.

• 1 February 2008 | Updated 14 October 2011

The black flower wasp, Discolia soror, is around 20-30 millimetres long and has iridescent blue wings. Its legs are covered in short bristles.

Male wasps are more slender than the females and have longer antennae.

These wasps are found throughout mainland eastern Australia and are often seen in open bushland and suburban gardens.

Black flower wasps are solitary and do not make communal nests.

However, in mid to late summer, they often form small swarms flying low over areas such as:

• turf
• shrubs
• compost heaps.

  Larvae of the black flower wasp, Discolia soror are useful parasites of lawn scarab grubs.

Adult wasps can also be seen taking nectar from flowers.

The adult females are large and powerful wasps and are designed to dig.

They burrow into the soil to locate scarab grubs (from beetles such as the Christmas beetle), which they sting and lay an egg on.

When the larva emerges, it feeds on the still living scarab grub, which provides a fresh food source until the wasp larva finishes its development.

The adult wasp emerges the next season.

Black flower wasps can be useful predators of scarab grubs which are pests of lawns.

They also pollinate native plants.

Female black flower wasps can sting but rarely do, as they are not aggressive. It is not necessary to control them.

CSIRO Entomology is not currently researching black flower wasps.

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