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Aphelinus abdominalis

Parasitic Wasp of Aphids

The parasitic wasp Aphelinus abdominalis occurs in large areas of Europe and Asia. It is a member of the familyAphelinidae, to which also the whitefly parasites Encarsia formosa and Eretmocerus eremicus belong.
An adult Aphelinus abdominalis is on average 3 mm long, and has relatively short legs and short antennae. The female has a black thorax and a yellow abdomen. Males are somehow smaller and have a darker abdomen. Usually, there are as many males as females. Aphelinus does not often fly. When a female is looking for aphids, she walks rapidly on the leaf. When she has found an aphid, she touches it with her antennae, turns around, raises her wing tips and injects her ovipositor in the aphid.
Oviposition takes about 20 to 60 seconds. Aphelinus can parasitize any aphid stage, even alates (winged aphids). TheAphelinus larva develops in the aphid. At 20°C (68°F) it pupates after 7 days and transforms the aphid into a black mummy. Eight days later an adult Aphelinus leaves the mummy.
Characteristic for Aphelinus is the long active oviposition period. The first days after emergence the adult female has not yet started to lay eggs at full speed. Oviposition reaches cruising speed on the 3rd or 4th day. From then on she parasitizes 5-10 aphids per day, and keeps on doing so for about 8 weeks. Aphelinus abdominalis also feeds on aphids (host feeding), in which case the female punctures an aphid with her ovipositor, turns around and sucks the body contents of her prey. She can also feed on aphid species which she does not parasitize. Moreover, Aphelinus can also eat honeydew.
Aphelinus can distinguish parasitized from non-parasitized aphids (host discrimination). Only very rarely the female will deposit a second egg in an aphid that has already been parasitized.For a good activity Aphelinus requires enough light and sufficiently high temperatures. Although some hyperparasites of Aphelinus are known to exist, in practice it is not a problem, as it is the case with Aphidius colemani.

Advantages:

  •  Applicable in many crops.
  • Longevity
  • Host feeding.
  • No problems with hyperparasites.
  •  Parasitization is easy to recognize (black mummies).