Monarch Caterpillars in winter

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  • #56816


    I am in Levin in the NI and have around 50 caterpillars in various stages on swan plants in my greenhouse. Some are still munching away whilst others seem to be almost comotose. There are some that have gone to chrysalis stage. Will swan plants survive through winter in my greenhouse, and more importantly, will the caterpillars and chrysalis?

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  • #61272


    This is the first year that I have observed them clearly going comatose as it got colder. It was interesting to find some smaller ones arched as if about to take another bite but then just didn’t do it. I cut a couple of branches with them on and brought inside but it made no difference. One by one they died, so I didn’t bring anymore in. Now that I have plenty of food, I am taking a more “hands off observation” mode and allowing nature her brutal beauty as well as her delights.



    had my last chrysalis e close last night. a very nice male. weather is vile so he will be in shelter up on my deck till weather improves sometime .. might be next week.



    The swan plants should be ok providing they don’t get frosted or get their roots too wet and don’t drain. Mind you it depends how long you have had them, I always expect to lose some older plants (more than a season old) every year.

    I’m in Wellington and all my caterpillars are finished now, I got some very big ones inside a few weeks ago and they have pupated. The smaller caterpillars tend to go comatose and stop eating and die. That happens even if I get them inside. The lack of natural light can’t even be compensated for with warmth. So thats just how it is and I’m just happy i saved some of them.



    That’s really interesting as several of our caterpillars outside (we’re in Marlborough) are exactly like that – in a comatose state hardly eating anything or moving. A couple have even just fallen off the plants for no obvious reason.



    Given the light conditions this time of year … short days, low light, cloudy conditions often etc. I’ve decided to experiment with artificial light as well as natural light. So I’ve bought in my last 4 caterpillars and put them in a small butterfly castle with cuttings of swan plant. The castle is light and easy to shift round. so far I’m getting a good response from my 4 amigos, they have lurched back from comatose to full eating mode. I’ve got them in the house overnight and leave a light on till later evening and put them in well lit windows in the morning … they can go outside in the sun today when it warms up. Even if one makes it through it will be better than watching them all die.



    Leslie is spot on. Day length is as important as warmth. Not every caterpillar is destined to become a beautiful butterfly – some are going to become food for other species, even the soil. It’s part of Nature.

    Celebrate your successes! And keep up the good work.



    I’m in Wellington. Same thing happening with my caterpillars. I have a hothouse too, and I’ve come to the conclusion after several years of observations that the length of daylight is as important as warmth. I have about 5 caterpillars left in hothouse that are more or less comatose, I don’t expect them to survive long enough to pupate. Of the six bigger cats I bought inside last week, two pupated, 2 were pupation fails, one just went comatose and died and the other is comatose. All caterpillars had ample food and warmth and exposure to whatever light there was available. So its just the time of year and I don’t think there is much you can do. I have 10 chrysalids left I have inside that I hope will survive. Your swan plants should survive overwinter unless they are exposed to frost and too much rain where they can’t drain, and of course if they are not too chewed up and have very little or no leaves left.
    good luck and just think of the successes you have had 🙂

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