What are these flys that kill my chrysalis?

This topic contains 5 replies, has 3 voices, and was last updated by  NormTwigge 2 years, 2 months ago.

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  • #49916

    MistySpills
    Participant

    Hi there,

    New to this forum and have been raising monarchs for the past 2 years.

    Anyways come February my chrysalis are under attack from wee black sandfly looking flys..
    They lay either on the J shape caterpillars or on the chrysalis.. I bring my chrysalis inside to avoid this happening but if I can figure what these wee bugs are I can hopefully find a solution before next year!

    I’m not sure how to attach a picture otherwise I would to help identifications purposes.

    Any help or advise would be greatly appreciated:)

    TIA

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  • #49981

    NormTwigge
    Keymaster

    Hi MistySpills, Your photos were forwarded to me, but are a little hard to see for positive ID. But together with your description, I would be reasonably sure they are
    the Chalcid wasp Pteromalus puparum, which you can google to check. If they were on the “J” caterpillars and the newly formed chrysalis, it would verify them. The wasp will wait on or near a “J” caterpillar until it sheds its skin, and while the chrysalis is nice and soft the wasp will inject eggs into it. A female wasp is capable of injecting 100 plus eggs, and 120 wasps have been recorded emerging from one chrysalis , but once the pupal case hardens it is safe from the wasp. If your chrysalides have not produced a butterfly after a good two weeks, and are appearing an odd colour, it’s a sign they could be infected. The wasp grubs residing inside can withstand freezing temperatures for several days, so seal the chrysalis in a plastic bag and dispose of it rather than freeze them, as once the adult wasps emerge they will immediately mate and look for more prey.

    #49943

    Jacqui
    Keymaster

    Got your photos and have sent them on to someone who I hoped would respond… but maybe he’s on holiday. Try posting the photo to Naturewatch NZ OR you could try the FB page identifying insects.

    Please let us know when you find out!

    Jacqui

    #49933

    MistySpills
    Participant

    Heya, I sent an image to your email, best picture I could do.. located in ashburton

    #49932

    Jacqui
    Keymaster

    Whereabouts are you, MistySpills?

    #49930

    Jacqui
    Keymaster

    Would be good if you could send me a photo, please. Just attach it to an email to trust at monarch dot org dot nz.

    I have heard of this sort of thing but fortunately don’t have it happening here -although I did just find one parasitic wasp in my butterfly house. 🙁

    Ichneumon 'Echthromorpha intricatoria'

    The one I found (above) is the Ichneumon wasp Echthromorpha intricatoria. Norm tells me they don’t usually infect monarch pupae, but a curse for admirals. Only one egg is deposited per pupa. Of course, one wasp can lay more than one egg!

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