Butterfly FAQ: Pros and Cons of Tropical Milkweed and What to do with a Winter Monarch Butterfly Caterpillar or Chrysalis

Several emails like the one below landed in my mailbox this week seeking counsel on what to do about late season Monarchs.

Hi Monika,

My friends found seven Monarch caterpillars on a well- protected piece of milkweed.  Six are gone, but one spun a chrysalis that they are protecting.  Do you have any advice?  We are wondering how long it will be in the chrysalis state in the winter.  Thanks for any advice you can give.

Dale

I would bring it inside, Dale–but that’s just me.

Usually it takes 10 – 14 days to eclose, or become a butterfly, but cooler temps can extend the process.  Caterpillars I

Monarch caterpillar makes its "J" shape and readies to form its chrysalis, 12/21/2011 in my kitchen.

found on potted milkweed in mid December and brought inside hatched just last week and flew off on a warm 70-degree afternoon. But it could easily have gone the other way, with an ice storm hitting just as my butterflies hatched.  Then what?

Deciding whether or not to adopt in-process butterflies during the off-season always presents a quandary. Questions to ask:

1. Do you have nectar available? Newborn butterflies generally don’t need to eat for the first 24 hours, but then they’ll need sustenance.
2. What about host plants?  A butterfly’s first priority is to mate (for males) and lay eggs (for females) on their specific host plant.
3. Will the weather cooperate?  Butterflies don’t fly when it’s less than 65 degrees.  Most will die with a freeze.

With our crazy Texas weather, Monarchs and other butterflies can hatch throughout the year depending on temperatures and host plant availability.  As noted last week, Monarchs are reproducing regularly on the San Antonio River — even into January.   Whether or not the eggs of those late season couplings make it to the butterfly stage is a crap shoot dictated by Mother Nature.

Monarch butterfly about to hatch in my kitchen

Generally, if I have host plants, I take found caterpillars into my kitchen to increase their chances of becoming a butterfly.  Studies suggest that  caterpillars and eggs left entirely to nature have a 10% chance of becoming a butterfly.  When we lend a hand the odds are flipped–with a 90% chance.

What’s sad is when butterflies hatch and enter a world with no potential mates, no nectar and no host plants.   I once bought several chrysalises at Butterfly World, the Disneyland”

Tropical milkweed on the San Antonio River Walk 1/04/2012

of butterflies and a worthy destination for butterfly fans in Coconut Grove, Florida.  I returned to Texas in mid December with Luna and Polyphemus Moth cocoons, and a Giant Swallowtail chrysalis.

I pinned each to the curtain of my kitchen window as directed, providing the bright light that can speed up development.

The Luna Moth hatched beautifully and was released on a relatively warm January evening.  The Polyphemus Moth never hatched.   When the Giant Swallowtail eventually eclosed–about six weeks after purchase–an ice storm raged outside.  A week of cold and freeze followed.  The poor creature flailed around on my kitchen floor, refusing the cut flowers and diluted Gatorade I offered via Q-Tip. After three sad days, the Swallowtail perished.

For Monarchs, this may not be a problem if you have milkweed growing year round. The non-native but easily adapted Asclepias curassavica, sold in many nurseries as Tropical milkweed, provides nectar and host plant material and grows gregariously in pots that can be moved in and outside.

That said, some Monarch scientists, including our friend Dr. Lincoln Brower, worry that cultivating Monarch butterflies on Tropical milkweed year round can result in undesirable colonies of Ophryocystis elektroscirrha, or OE, a protozoan disease that infects Monarchs and other milkweed feeders. OE is present in the landscape but seems to especially flourish on Tropical milkweed in southern climates late in the year.  In colder climates and the wild, milkweeds die off in the winter, apparently purging OE to a large degree.

Scientists speculate that local OE-infested Monarchs will breed with migrating populations, possibly jeopardizing the migration.  Butterfly breeders and enthusiasts argue that OE is like staphylococcus–present in our populations and getting out of hand only under stressed circumstances.  Some believe that OE is simply a part of the evolutionary cycle, killing those butterflies less fit than others.

The answer, Dale, is that it’s a cold, cruel world for butterflies caught in flighty Texas winters–and an uneasy call for butterfly fans seeking to lend them a hand.

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