Sunday, January 1, 2012

Monarchs in Winter

We've been having typical Southern California winter weather: within a single week, we will have nights where it freezes, nights with heavy fog, and days ranging from 50 degrees to 70 degrees days.

On sunny days, we'll have monarchs in Archie's Garden -- sunning themselves on the milkweed, nectaring on flowers, and laying eggs just like it was summer. We have a lot of caterpillars! The milkweed doesn't seem to be able to grow fast enough to keep up with them.
Most of the caterpillars seem to be surviving even the freezing temperatures. In the early morning, before the sun warms them up, they can be found in strange positions on leaves, or even fallen down onto the pavement. Although they appear dead, they start behaving normally when the sun shines on them.
Dead? Nope, just cold!
These two guys look like they're frozen, but they're just waiting to warm up, and then they'll go back to eating.

We are still having caterpillars pupate. During this cold weather, the pupae are taking much longer to become butterflies -- we had one emerge yesterday after being in the Butterfly Fort for several months! This also is related to the temperature, we think. The pupae that are in sunny areas become butterflies faster than the ones in the shade.
This one took its time!

We're also seeing a larger number of caterpillars who don't pupate successfully, or pupae that are dying. It could be the cold, but there could also be disease. There have recently been a number of caterpillars who died suddenly, with symptoms that match those described on this page, and could be Nuclear polyhedrosis virus (NPV).


  1. oh my! Well I'm sure most of your caterpillars make it to Monarch state :)
    Good luck in 2012!

    One of the goose milkweeds you gave me is finally growing in the front yard, and the other is now in the mountains as a memorial planting to my friend's dog. I've got two other milkweeds that are growing slowly and we hope to see monarch this year! Thank you!

  2. Hey Mary, nice to hear from you!

    We're actually starting some milkweed indoors, since every time we plant outside the plant will get eggs laid on it, no matter how tiny. We can't grow it fast enough! so trying to give some new plants a head-start before they end up chewed to sticks.

    If you want to adopt a caterpillar for your milkweed, we've got a couple we'd be happy to send to a new home...our milkweed supply is rapidly being eaten and we're afraid we'll run out before we can grow more. (that's the nice thing about the gooseplant; it grows faster than the tropical milkweed.) Feel free to drop a line anytime and happy growing!

  3. I'm having a lot of trouble here too. Dead caterpillars, chrysalis that never hatch, turn black and die. I wonder if the weird weather is playing havoc with plants and insects, stressing them out. Two weeks ago we had a heat wave, then rain, cold temperatures, now again a heat wave, Santa Anna winds, Indian Summer, whatever... This is crazy for January in L.A. It must confuse the hell out of everything.

    This is my third year growing milkweed and I've never seen so much death and holocaust. I haven't raised a single butterfly, Nearly a hundred caterpillars decimated my grove of 150 milkweed plants, only to all die from a black death.

  4. We have also had a lot of failures this year, and sometimes it's unclear why. Tachnid flies and the dreaded OE protozoans parasitize cats and chrysalides, and I think you're right--the crazy weather may stress the population and temperatures that approach freezing take a toll.

    If you'd like to learn more about causes of caterpillar/chrysalis death, check out Be warned--the photos are a little icky, but better to learn so you can remove infected remains and help prevent further deaths. Good luck!