Writhing caterpillars

This topic contains 5 replies, has 2 voices, and was last updated by  bright123 3 months, 3 weeks ago.

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  • #56181

    bright123
    Participant

    Hi there,

    This summer is my first raising monarchs. In the last week or so, I’ve had a number of caterpillars suffer from what sounds like poisoning. They writhe on the ground until they eventually die. It is happening to large and healthy looking caterpillars and seems to come on suddenly. I have euthanised 6, which was very hard but I couldn’t bear to see them suffer any longer. I have another 6 suffering from the same condition today that I have rinsed and isolated in containers; one looks it will survive. The rest are very doubtful.

    I am perplexed as to the cause but have determined that the caterpillars on plants are fine, but those that venture over ground start to suffer, and I am pretty sure it’s centralised to one particular area of ground right in the center of the garden bed. We had a day of very bad weather that just preceded this and so I have a theory that I wanted to run passed to see if feasible? My suspicion is my cat has used the garden bed as it’s toilet (in fact I caught the darn thing doing just that this evening so this is confirmation of my suspicion). Could cat urine poison a caterpillar if it passed over the affected area later? He was given flea medication about 7-10 days preceding the poisoning, so I’m also thinking this is either being rubbed/shed as he passes through or perhaps it’s present in his urine – what do you think?

    Also if you have any advice about what to do, I’d love to know. I’m not sure whether it is kinder to euthanise or attempt to save.

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  • #56440

    bright123
    Participant

    Just an update: so I lost a number of caterpillars with these writhing symptoms in the end which was really hard, especially because it was so perplexing. And I had all sorts of theories swirling in my mind. Another died while pupating, and another went stiff and died from something else. So I was left with just two from this problematic bunch/generation, but wonderfully one of them grew to become one of the plumpest caterpillars I’ve ever seen and pupated successlly the other day. Hooray! I now have about 8 new tiny ones hatched from recent eggs, and thankfully new leaf growth for them to munch on. Almost all the successful chrysalises that formed in January have hatched and flown off now, so there is a gratifying array of empty crhysalis shells adorning the plants and nearby shrubs. So I hope for a mild autumn for this late generation. What a learning experience it has been! As my first foray into rearing caterpillars in the garden, I have learned:

    Leave them alone
    Things happen; some won’t make it
    They wander around so watch your step
    Some choose the weirdest places to pupate
    They miraculously can hang on to the swan plants in the strongest Wellington wind
    Crystalises can sometimes take a long time to mature and it’s ok – mine seemed to take up to 4-6 weeks
    They are fascinating in their quiet way 🙂

    This forum is a wealth of information and support, so thank you!

    #56202

    bright123
    Participant

    Thank you for that LeslieD. I found it very encouraging and uplifting, and a good reminder to celebrate the good things. Just what I needed! 🙂

    #56186

    LeslieD
    Moderator

    unfortunately lots of bad things can and do happen to living creatures and butterflies seem to cop more than their share. So, yes celebrate the successes 🙂 we sure need them! It is lovely to see the butterflies in the garden, makes it worthwhile.

    #56185

    bright123
    Participant

    Hi there, thanks for that. I didn’t think of that, but had planted some new plants recently and the caterpillars have eaten their way through those happily enough but perhaps the potting mix has fertiliser in it, and that was washed to the surface during the heavy rain I mentioned… I ended up removing the top tool just in case (though I’m really just trying anything at this stage). Sadly the 6 caterpillars I isolated all languished further overnight. The one I had hoped woukd recover was looking ok at 1am but he had been throwing up a lot, by 6am he was a quarter of his size and convulsing/writhing like the others. I euthanised them all this morning. I am so gutted. No more writhing caterpillars this morning outside but time will tell… Two butterflies have emerged so I can take some comfort in that.

    #56183

    LeslieD
    Moderator

    I had a similar thing happen when I used thrive fertilizer a few years ago. But that was the caterpillars on the plants I fertilised that died. I kind of doubt that urine residue would do it … but I can’t state that as an authority. I’d be more inclined to think of a fertilizer on the ground. Sadly I don’t think you can do much to help them once they are poisoned.

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