Tuesday, March 29, 2011

A tiny Parasitoid Wasp on Campus

There are only small patches of planted,  native vegetation on the University of Arizona campus. I don't know whether that is because of a great old arboretum that used to take up most of the campus area - many of the old trees have made room for building expansions by now, and the last freeze killed a number of others - or if there is an attempt to match the old fashioned red brick buildings with fresh green lawns and ivy....

But if you offer just a few yellow flowers (Desert Marigolds) and budding prickly pears with extrafloral nectaries, the bees and wasps will come.

On the fat Santa Rita Opuntia pads, washed lavishly in silver, turquois  and hot pink, a little speck of yellow and black stands out. It's only about 4 mm long, and in the glare of the mid-day sun I have to take a macro photo to get a better look.

The tiny abdomen, huge hind femurs and sickel-shaped tibiae tell me that it is a male chalcid wasp of the genus Conura. Against hope it is identified quickly on Bug Guide by Ross Hill as C. side (Walker 1843).

Most Chalcid wasps are parasitoids of other insects. They lay their eggs into eggs or larvae of Butterflies, Beetles, Flies, True Bugs, Spiders, and even some Nematodes (Worms). Their larvae develop in the living host, but the host usually dies when the chalcid larvae break through the skin to pupate externally. Chalcid wasp distribution covers the holoarctic as well as the tropics. The genus Conura is most widespread in the tropics.
 Chalcidoidea are ecologically important, morphologically and biologically extremely divers, and phyllogenetically very challenging. With 60, 000 to 100,000 species and a worldwide geographic range they will keep researchers busy for a long time. To learn more go to the Chalcid site on line which offers lots of information.


  1. From Henry Hespenheide:

    M -
    > Re your post on your website: Conura is a big genus and some species groups are very difficult to ID to species. Actually, Conura species are relatively large in size compared to many chalcidoids. The largest number of Conura species are pupal parasitoids of lepidopteran larvae, but, as befits a large genus, they have a variety of hosts. I first noticed them when they emerged from pupae of leaf-mining buprestids. I've also reared them from hispine chrysomelids, maybe as many as 20 species in Panama and Costa Rica from leaf-mining beetles.
    > H

  2. I had no idea there were so many species of these. Interesting!

  3. What a facinating wasp! I don't think we have anything like it here. He looks so clunky.

  4. Hi Margarethe,

    Your blog is great. I came across it while trying to find out for a friend something about some wasps that crawled out of a monarch chrysalis this morning. The chrysalis was being monitored for a school group and the butterfly was going to be a star -- the kids are in for a surprise but will probably learn something new.

    I live in New York City and I write a blog about urban wildlife http://www.urbanwildlifeguide.net. I have just reached the stage of exchanging links with others. Would you like to do this? I would be thrilled to add your blog to my growing list. Take a look and see if you think mine would be a good fit here, and let me know, ok?

    Best, Julie