Caterpillars vomiting red and dying

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  • #50702


    Hi all,

    I have another question. I have seen plenty of posts about caterpillars vomiting green, after being exposed to insecticides. Has anyone else had the experience of them vomiting red?

    I had 4 big cats about a month ago, healthy as anything. Food had been mostly milkweed with a bit of mothvine thrown into the mix, all cuttings from my garden. All rinsed for 10 seconds in a 5% bleach wash then rinsed off twice with clean water. Then overnight they stopped eating and went limp, folding over backwards or curling up in the bottom of their enclosure and vomiting a red tinted liquid. This lot died.

    I was more careful with my next two, I washed all the cuttings extra careful but without bleach just in case it was bad bleach. They were fine for 2 weeks then again in their 5th instar also exhibited lethargic systems and started to bend over backwards. I got to these ones quicker and put them on new leaves plucked from an indoor baby swan plant. I though they were goners but to my surprise these two pupated, but they were still very sickly looking and I’m not sure whether they will eclose.

    I still am unsure what has caused this, though there is some dead grass down the end of the shared driveway which looks like it might have been sprayed. Have not used fly spray or plug ins in the home. I have successfully reared about 40 butterflies earlier this year, but am hesitant to bring any more caterpillars inside this season in case it’s something I’m doing. All the posts say toxicity leads to a green discharge. Does anyone what causes red discharge from a sick cat?

Viewing 5 replies - 1 through 5 (of 5 total)
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  • #50759


    The colour of the vomit may vary with different chemicals. The plants may have been exposed to overspray, and if it was a systemic spray, which is absorbed into the plant, no amount of washing will remove the toxicity.



    Hi Trez_a

    Im so glad this dear one has survived! Yay!!
    Here’s to a successful trim – and to her’him flying off to live their life.

    After experiencing a couple of bent tips – I now arrange a hand-width drop zone for the wings to open. I also bend back leaves of plants in that zone, bend the plant’s stalk over to create more room, and put fallen pupas in cradles to allow that hand width of space.
    Low-lying pupas also get elevated on to shelves with an overhang! This includes not only those on short plants, but includes the cats’ outdoor drinking bowl, flower trays, and a small watering can!! All are perenial pupating places 🙂

    Best wishes



    Hi Jacqui and FiLeBeau,

    A followup. One the chrysalides, the sicker of the two has died in his shell. The other against all odds has emerged!! The tips of his wings touched the floor and folded a tiny bit, but he took a great big drink last night, so I’m hopeful with a bit of TLC and a wing trim, he might just make it 🙂



    Im so very sorry to hear this.
    I have had poisoned caterpillars this season with no vomiting or symptoms at all.
    It was the Butterflies and pupas that showed the toxic effects.

    The caterpillars urination was acid blue/grren with red (blood Im presuming), and the lining of the pupa was thickened and acid green or blue.
    I havent encountered red vomit – perhaps its blood, or a different toxin.
    Again. Im so sorry.




    Hi Trez_a – these symptoms are new to me! A horrible experience for you.


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