Identification request
2020-01-21T20:08:52.6717393Z
   2
Parasitoid wasp on Leaf miner - seeking possible ID
Dear Pestnetters Please find attached a picture (×10) of a wasp (picture attached) that is seemingly a parasitoid of one of the long bean leaf miner pests, supposedly Lyriomiza spp. Wasps are about 3 mm in length. Many thanks Mani
Fiji

Responses

   0
2020-01-21T22:38:46.0977895Z

Hi Mani,

It will be an eulophid wasp, try this key to SE Asian Eulophidae parasitising agromyzids

   0
2020-01-25T22:14:19.7851273Z

Hi Mani

Expanding on David's good suggestion, your image of the wasp reared from a Liriomyza sp. (I would love to examine any Liriomyza species from Oceania) indicates that you have reared a female Hemiptarsenus varicornis. Family Eulophidae, Subfamily  Eulophinae, Tribe Eulophini.

From the image (and knowing it was reared from an agromyzid)

  1. there is a white tip on the final segment of the antenna
  2. the scape (first segment of the antenna) clearly exceeds the vertex of the head. This is well-illustrated in the Fisher et al. (2005) page on the genus Hemiptarsenus (mouse over links in the text to see the images).

You are also likely to find male H. varicornis which have very distinct three branched segments in their antennae.

When you look at the taxon page for Hemiptarsenus varicornis on the Fisher et al. (2005) Key to SE Asian Eulophidae Parasitising Agromyzids, https://keys.lucidcentral.org/keys/v3/Liriomyza/species_pages.html you can see a very good set of images, which expand when you mouse over them. Additional links can be found on the Web Resources page of the Polyphagous Agromyzid Leafminers website. https://keys.lucidcentral.org/keys/v3/leafminers/webresources.htm

Hemiptarsenus varicornis is the most frequently-recorded parasitoid of agromyzids in Australia and is widely established in Asia, Oceania, Africa and southern Europe. Waterhouse & Norris (1987) listed the species (as Hemiptarsenus semialbiclava - an early synonym) from Samoa, Vanuatu, the Cook Islands and French Polynesia. Note that they incorrectly included the species in the family Pteromalidae, rather than the Eulophidae.

Hemiptarsenus varicornis is an ectoparasitoid - the egg is laid beside the host larva and the wasp larva then feeds on the host larva before pupating beside the host's remains. It is strongly synovigenic (it has none or very few mature eggs present at eclosion and females need to feed on host nutrients for egg development). Host killing of Liriomyza trifolii by H. varicornis has been observed in three ways: parasitism (26% of mortality), host feeding (58%) and host stinging without host feeding (16%) (Cheng et al. 2017). 

Kind regards

Peter Ridland

The University of Melbourne

References

Cheng X-G, Cao F-Q, Zhang Y-B, Guo J-Y, Wan F-H & Liu W-X. 2017. Life history and life table of the host‐feeding parasitoid Hemiptarsenus varicornis (Hymenoptera: Eulophidae). Applied Entomology and Zoology 52, 287–293.

Fisher N, Ubaidillah R, Reina P & La Salle J. 2005. Liriomyza parasitoids in Southeast Asia. Available from: http://keys.lucidcentral.org/keys/v3/Liriomyza/index.html

Waterhouse DF & Norris KR. 1987. Liriomyza species. Diptera: Agromyzidae, leafminers. In: Biological Control: Pacific Prospects. (eds DF Waterhouse & KR Norris) pp. 159–178. Inkata Press, Melbourne.