wasp parasitism- what stages?

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  • #15415

    joanna
    Participant

    Can anyone clarify this for me? Do ichneumon wasps parasitise late instar Red Admiral caterpillars or only the pupa when it is at the early soft stage?

    My attempt to raise a few wild-collected larvae and pupae last summer resulted in either wasps emerging or non-hatching altogether.

Viewing 14 replies - 1 through 14 (of 14 total)
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  • #30858

    NormTwigge
    Participant

    A pupa infected by Echthromorpha intricatoria tends to slowly develop a rust or coppery colouring, instead of the usual brownish or greyish colour.

    #30838

    joanna
    Participant

    Great info again- thanks Norm. I’m in Wairarapa (Masterton) but my fieldwork often takes me to Eastern Wairarapa hill country where I come across pockets of ongaonga, usually on the margins of forestry/sheep farm. I suspect the level of parasitism must be high here too (I’ve read that paper relating to this issue from Banks Peninsula research).
    I’m keen to see what hatches out of the pupae I collected recently from the backblocks! Is there any way of telling if they are incubating an ichneumon wasp instead of a butterfly or do you have to wait until they emerge?

    #30827

    NormTwigge
    Participant

    Photo posted to the “Photos” section above showing a Yellow Admiral in a typical ovipositing stance with the body held high and the abdomen curved down. The first instar larvae usually migrate to the young tips of the plant where they spin a silk cover to hide under. Also look on the underside of the leaves for 2nd instar larvae, after which they pull a small section together at the bottom or edge of the leaf. Only when they are larger do they pull the whole leaf together as a “tent”.
    What area are you in Joanna?

    #30825

    joanna
    Participant

    OK..I’ll try that….and hopefully when I visit that site again next month I will be able to see evidence of ovipositing! I did wait there for 10-15 mins. Is it obvious when egg-laying is occurring ie Does the abdomen of the butterfly curve noticeably?
    I recently also returned to the site where the pupae I collected last summer only produced ichnuemon wasps. To my dismay there wasn’t any sign of larvae or pupae at all (and it’s a large patch of ongaonga). No butterflies around either. I couldn’t help wonder if the wasps last year wiped them all out in that particular spot.

    #30824

    NormTwigge
    Participant

    Joanna – if there are Red Admirals flying around a large patch of ongaonga I would bet my last dollar it is only a matter of time before they oviposit. The lack of larvae could reflect wasp predation. Catching butterflies with a net only requires a little practice, and netting white butterflies around the garden will soon develop the knack. But beware of trying to net butterflies flying too close to ongaonga or any other spiny growth such as blackberry bushes as the net can get hopelessly entangled. Good luck.

    #30822

    joanna
    Participant

    Yvonne – no worries – I realised you were referring to another species of wasp parasitoid.
    Norm – thanks for your help. I’m not sure I would be confident netting a female! Yesterday I was lucky to find a few Red Admirals flying about a large patch of ongaonga so I sat and watched for a time. None seemed to be actually ovipositing, but would settle on a nettle leaf for a bit then flutter off. No ova were evident on the vacated leaf. I did see 2 adults interacting in the air, spiralling around each other for a bit.
    There were lots of pupae in this nettle patch so I brought a few home to see if I have a repeat of the ichneumon wasp hatching that i did last summer. Also collected a couple of late instar larvae for rearing inside. Couldn’t see any small larvae at all which seemed odd.

    #30820

    Jacqui
    Moderator

    The glossary on our website

    https://www.monarch.org.nz/projects/glossary/

    clarifies a lot of the terms I get confused with. I go there frequently.

    #30819

    NormTwigge
    Participant

    No worries Yvonne, lepidoptera and the relating subjects are a huge learning curve, and I am still learning. There are many types of wasps, from the paper wasp through to tiny wasps that lay their eggs into other lepidoptera species eggs. The two types mentioned above are the main parasitoids
    and vigilance is one of the keys to rearing caterpillars. Transferring late instar caterpillars into the likes of a castle and having them pupate there is a good system of preventing infection from parasitoids.

    Parasite – an organism that feeds and grows on a different organism (host)and contributes nothing to the host, rarely killing it.

    Parasitoid – an organism that feeds and grows on its host and usually causes the death of its host.

    #30817

    YvonneWallis
    Participant

    Oh..thanks for that Norm,
    When I saw the admirals and wasps I jumped to the wrong conclusion as I didn’t know they had this other wasp predator that laid eggs inside 🙁
    Sorry for the misleading information, Joanna

    #30813

    NormTwigge
    Participant

    Just to clarify – the wasp Yvonne refers to is the chalcid wasp Pteromalus puparum which is capable of depositing over 100 eggs into an Admiral pupa, and are known to infect Monarchs also.
    The ichneumon wasp Joanna refers to is considerably larger and a single wasp emerges from the pupa, chewing away most of the bottom end of the pupal case to emerge.

    #30812

    YvonneWallis
    Participant

    When the caterpillar is going into the J to pupate they will sit on the J and it is a good time to be on guard and kill the wasps…they carry on when it is newly formed and soft so you have to keep an eye out..sometimes you will see the chrysalis moving and the nasty little creatures are on there and might have already laid their eggs. If a chrysalis has a small hole in it..like a pin prick size then the wasps have been in it and have came out or coming out so squish it before anymore come out.

    #30811

    Jacqui
    Moderator

    Hi Joanna

    This is a great first step:

    Caterpillar Castles

    #30808

    joanna
    Participant

    Thanks Norm. I don’t have a butterfly house (yet!) so will have to stick with trying to raise a few wild-collected larvae in the meantime.

    #30805

    NormTwigge
    Participant

    Field collected Red Admiral pupae are commonly infected with the Ichneumon parasitoid Echthromorpha intricatoria, which are infected at early pupal development before the skin has hardened.
    The emergence failure of larvae that pupated in reared conditions may be a disease factor.
    The best way of rearing them is to net an ovipositing female which will lay eggs in captivity no problem, the adults can be found on a sunny day where the larvae/pupae were found.

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