raising Monarchs indoors

This topic contains 5 replies, has 0 voices, and was last updated by  Jennifer 8 years, 10 months ago.

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  • #14335

    Darren
    Participant

    Mary contacted Monarch Health (http://www.uga.edu/monarchparasites)

    and found that the ideal temperature range for raising Monarch Caterpillars is 18?-35?C

    The question was asked, would raising autumn caterpillars at this temperature end up fooling them into thinking they were summer caterpillars so that they would later engage in mating rather than over-wintering?

    This question was passed on to the Monarchwatch DPLEX mailing list and got some interesting responses.

    David James did his Ph.D on the "Overwintering Biology of the Monarch Butterfly in the Sydney Area of New South Wales". He found that it wasn’t the temperature that the caterpillar and chrysalis experienced that determined whether it migrated and entered reproductive dormancy or became sedentary and reproductive. Instead it was the temperatures experienced by the Monarch Butterfly during the first 3-5 days of it’s adult life that was the deciding factor.

    Temperatures below 15-18C for 48-96 hrs caused migration/dormancy and temperatures above 15-18C resulted in breeding. Day-length did not appear to play a role in determining reproductive status, neither did the conditions experienced by the caterpillars.

    This is an interesting result because in North America the migration and over-wintering behaviour _is_ thought to be triggered by the day-length somehow. But exactly how this works is not completely understood. For example Monarchs at the latitude of 50 degrees North (e.g. Vancouver) start migrating when the day is about 15 hours long, but the Monarchs at the latitude of 30 degrees North (e.g. Louisiana) don’t start migrating until the day length has dropped to about 12 hours long. (By contrast Invercargill is 46.8 degrees south, and Cape Reinga is about 34.)

    So the bottom line seems to be that there is unlikely to be any ill effects from keeping your caterpillars and chrysalises indoors at an ideal temperature of 18?-35?C. But once the butterflies emerge it would be better to release them promptly, or transfer them to somewhere where they can experience temperatures similar to those outside and set their behaviour accordingly.

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  • #24728

    Jennifer
    Participant

    One of the predicted effects of global warming is more extreme variaiation in weather and temperatures. It would be interesting to have some rearch on that! Aren’t I greedy!

    #24725

    Darren
    Participant

    Just found a paper relevant to this discussion.

    http://realscience.breckschool.org/upper/research/Research2009/Nimmer_DSpaper.pdf
    Nimmer, Emily, (2008), Monarch Butterflies (Danaus plexippus) as Bioindicators of Global Climate Change.

    She was examining the effects different kinds of heat stress had on Monarchs. As part of her conclusion she notes “I found that higher nighttime temperatures did not affect probability of adult butterflies being infected with spores, having crumpled wings, or having asymmetric wings, suggesting that heat stress did not affect overall adult butterfly health (p>0.05) (Figure 18-26).”

    However she also points out that “A study by Zalucki (1982) established that prolonged exposure to temperatures of 29.0 ?C can be detrimental to monarch larva development, and further work by Malcolm et al. (1987) showed that constant exposure to extreme temperatures over 33.0 ?C for five days can be fatal to monarch larvae (9,10).”

    Admittedly that refers to constant temperatures day and night such as in an incubator. But based on this I would revise the figures supplied by Monarch Health and recommend a temperature range of 18-28?C.

    #24698

    Jennifer
    Participant

    Oh well, it could be timely in the autumn of next year.

    #24696

    Darren
    Participant

    I was thinking just that as I wrote it, but the deadline was a few days ago. Maybe next time.

    #24692

    Jennifer
    Participant

    This is very interesting Darren, might it be a potential newsletter item?

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