Strange summer

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  • #14255


    I ran a survey some months ago about the unusual lack of Monarchs around this summer. I would say that 90-95% of people that I have met, or who have phoned the MBNZT, or have written in, have reported "few Monarchs".

    (Now I know that for some of you that has not been the case – but people are happier sharing the good news, and not saying they have had few… it’s like they might have done something wrong. Who wants to talk about their bad news?)

    Here in Northland the drought has been very unusual, and one of our members (who usually has dozens of Monarchs laying, so much so that she can run out of milkweed) writes:

    "Not One Caterpillar to be seen this year! NOT ONE!! Why? Maybe becaue of the very dry hot summer? Making the white juice in the swan plant (Gomphocarpus fruticosus, formerly Asclepias fruticosa) too concentrated and not suitable for the caterpillars?? I have seen a few butterflies around but mostly to get nectar from the swan plant flowers."

    Could this be an explanation?


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    You can bring your chrysalis inside and I usually just mist mine with a fine spray of water I keep in a spray bottle.
    This stops the shell form drying out to much. But remember don’t use fly spray or any cleaners etc near the chrysalis.
    Put some newspaper underneath to catch any fluid that will come out when the butterfly emerges.




    Hi Eleanor, I am in Christchurch and I brought my last two Pupae inside as it was getting too cold at night. I had them inside for a few days and they both hatched out perfectly. I set them free the next day .
    Mary L




    Last week a couple of our chrysalis hatched during that really stormy wet day. The next day the butterflies wings were all crushed and deformed. Is that because their wings were too wet to spread out?

    We’ve got more on the tree that look ready to hatch today but a storm is coming – so I’ve snipped the twigs that they were on and and brought them inside. I’m hoping they might have a better chance to dry their wings inside? I’ve put the twigs into a pot plant but read some of the posts and I’m a bit worried they might not hatch inside? Should I mist some warm water over them or put them back outside?

    This is the first year we had swan plants and not too sure about how to look after the chrysalis and butterflies.




    Could be. Hostplants can have varying levels of toxin, both between different species and also within each species. for example

    A. incarnata 111 (42?199)
    A. curassavica 415 (227?638)
    A. fruticosa 345 (119?719)

    “It’s the first bites that count: Survival of first-instar monarchs on milkweeds”. Austral Ecology 26: 547-555. (

    However if that was the problem I would have expected to still see eggs and small caterpillars, but high mortality in the first instar. But not alot is known about this:

    All milkweeds contain toxins, called cardenolides, which the monarch has adapted to be able to ingest. These toxins serve to protect both the plants and the monarchs from predators. Scarlet milkweed contains much higher amounts of toxins than native milkweeds. Monarchs do not discriminate between Asclepias that have high or low toxicity; higher toxicity milkweed may hinder larval performance, but it may also provide additional protection from predation. More research into scarlet milkweed’s effects is needed because it may have adverse effects on monarchs that we do not yet understand.

    A study was done on the effects of cardenolide levels on the Oleander aphid (Aphis nerii) using A. curassavica and A. incarnata, but it found no difference in the aphid populations. “Density-dependent reduction and induction of milkweed cardenolides by a sucking insect herbivore.” Journal of Chemical Ecology 30(3): 545-561. (

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