Judy Nevin of San Antonio was concerned about Monarch chrysalises she’d been monitoring in her garden this week. One had crawled under some plant cloth and frozen when the temperatures dipped below 32. Another had relocated to a former basil plant and formed its green, gold-flecked container on a dead limb, perhaps to emerge on a day like those we experienced this weekend when the sun warmed parts of Bexar County to springlike temperatures in the 70s.
“I had two chrysalises until two nights before last,” said Nevin by phone. One froze and she brought the other inside.
Our schizophrenic weather, freezing one day and balmy the next, has provoked frequent questions from readers about what to do with chryalises found in the winter. Should you bring them inside? And why do they form away from their host plant?
Bringing a chrysalis inside for protection from the elements is a judgement call. We already covered the quandary of moving late season caterpillars indoors in this December post. The same logic applies to chrysalises. Will you be around to release the butterfly or do you plan to keep it inside if the weather is ornery? Do you have nectar for it–either artificial or natural? Depending on where you live and the time of year, the newborn butterfly may have few prospects for food or mating.
Again, there’s no “right” answer here.
As for caterpillars forming their chrysalises AWAY from their hostplants, this is common practice. We’ve brought hundreds of caterpillars and chrysalises inside, and yet it still provokes smiles when we find a chrysalis in an unlikely place.
We’ve found them under chairs, on curtains, napkins, blank walls, glass windows, and other unexpected locations.
Once a Swallowtail chrysalis wandered 20 feet from the host plant in my Austin apartment to form its chrysalis on the electrical chord of a flat iron. Another time a Monarch caterpillar I was transporting to a speaking event in my car wandered away during the drive. Later I found the chrysalis inside my summer straw hat. I moved the perfectly formed chrysalis to a stick, tying its silk button with dental floss to a horizontal branch so it could hang vertically until it was ready to emerge. A week later, it did, nonplussed.
We’ve also made the dreary discovery of a perfectly formed dead butterfly that eclosed and was belatedly found–under a couch, near a window, or on the floor by a glass door when we were away for the weekend. A sad event, and something to consider should you bring in a chrysalis from the cold.
Why do these intriguing creatures wander so far from what they know so well and what has sustained them?
Scientists suggest this is a survival mechanism. If a caterpillar forms its chrysalis on the host plant and other caterpillars defoliate it, that leaves the chrysalis more visible and vulnerable to predators. My personal unscientifc theory is that caterpillars need a quiet spot to transform themselves into a completely different lifeform. Growing wings and planning your first flight must require deep concentration.