A question about Echthromorpha intricatoria (Ichneumon wasp) behaviour

This topic contains 8 replies, has 0 voices, and was last updated by  Jacqui 3 years, 4 months ago.

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  • #14803

    Jane
    Participant

    This morning we had a great many of these hanging around a tree in our orchard. They were continually taking small flight, and then very briefly landing on each other. There were perhaps 50-70 of them, but no sign of any nest.

    Pete thought maybe they were mating, but I thought that only the queen was mated. We don’t know much about their behaviour though so would be grateful in anyone could shed any light on this activity. There were enough of them in a small area to put me off accessing my figs for fear of attack. Pete says this has been going on for a few days now. Any ideas from you entomology buffs out there?

    Jane

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  • #27238

    Jacqui
    Keymaster

    Yes, Anna, you’ve more than made up for your first experience. Good onya!

    #27236

    Anna
    Participant

    Norm, its good you have pointed out the differences, as I would have had no idea. I’ll keep a better eye out when I see one now.
    The very first 7x Admiral pupae I was given when I started raising Admirals…all emerged as The white spotted ichneumon wasp (Echthromorpha intricatoria) much to my dismay.
    So it made me even more determined to do my bit to protect any future Admirals.
    Since then, I’ve managed to raise and release lots thank goodness.

    #27234

    NormTwigge
    Keymaster

    Hi Jane,

    I was fairly sure you would be accurate in your ID but mentioned it anyway. The huge numbers in a group is most unusual given that they are a solitary wasp, but possibly a few recenly emerged females had attracted many males. April is the time when they are at their peak.
    Having probably detected the admiral larvae they will no doubt hang around for them to pupate, the wasp larvae will overwinter in its host pupae.

    #27232

    Jane
    Participant

    Hi Anna and Norm,

    No unfortunately I didn’t get a photo. I am sure of my ID though. We get them here every year, but I have never seen this behaviour before and in such HUGE numbers. Surprisingly though there are still plenty of Admirals flying around and lots of larvae on the nettles. I realise that it is the pupae that are attacked, but it seems there are many making it through to the butterfly still.
    Jane

    #27231

    NormTwigge
    Keymaster

    The native ichneumon wasp shown on the website Anna included above is the lemon tree borer parasite (Xanthocryptus novozealandicus) which is one of the good guys as it injects its eggs in the grub of the lemon tree borer, and other pests. The wasp locates the grub tunneling inside the wood, and using its ovipositer penetrates the wood to lay the egg into the borer grub. This egg hatches into a grub which in turn feed on the contents of the host grub.
    The white spotted ichneumon wasp (Echthromorpha intricatoria) the bad guy, self introduced from Australia, is the wasp that injects its egg into various butterfly and moth pupae, paticularly admiral pupae which are heavily targeted in the wild. Although very similar in appearance and sometimes hard to distingush when flying or on the move, the most obvious differences are X. zealandicus has distinctive white bands on its antennae and white stripes across its abdomen in comparison to E. intricatoria which has white spots on its abdomen.

    #27229

    Anna
    Participant

    Its good to see that Norm. I just googled native ichneumonid, and found this fairly interesting.

    http://www.terrain.net.nz/friends-of-te-henui-group/local-flies/wasp-black-and-white-ichneumonid.html

    #27227

    NormTwigge
    Keymaster

    Hi Jane,

    E. intricatoria are not harmful to humans, they cannot sting, and do not build nests. The female injects one egg into various butterfly and moth pupae with her ovipositor. Admirals particularly, occasionally monarchs and magpie moth pupae are targeted. It sounds a little unusual for so many to congregate in one area, are you sure you have identified them correctly? There is a native ichneumonid with very similar markings which is beneficial in the garden, any chance of a photo?

    #27226

    Anna
    Participant

    Jane, I don’t think they would attack you…but then I’m not an expert.
    If it was me, I’d get out there with a butterfly net, and bucket of really hot water to dip it in to with any I had caught, to try and reduce the numbers.
    Did you manage to get a photo?

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