A common quandary when blessed with the gift of caterpillars noshing nearby is whether or not it’s safe to relocate them once they form their chrysalis.
Tom Pelletier of the Ask A Naturalist website wrote today, explaining that six gorgeous Monarch caterpillars were busy at work on a milkweed plant in a yard adjacent to a high traffic sidewalk.
“Once the chrysalis is formed, can we move each one to a safer location in our back yard? Does it matter where the butterfly emerges, i.e. does it have to be on milkweed?”
The answers are yes, you may relocate the creatures once they make their chrysalis, and no, the caterpillars do not need to chrysalis on milkweed. In fact, Monarch and other chrysalises often are found as far as 30 feet from the hostplant where they ate their last meal.
Entomologists speculate that caterpillars leave their host plants to protect themselves from predators. “Caterpillars frequently strip the plant, so to form a chrysalis on a naked plant would leave them terribly exposed,” said Mike Quinn, an entomologist and founder of the Austin Butterfly Forum. My 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.
Given the above, and the high incidence of caterpillar mortality caused by birds, spiders and other predators, I would be inclined to bring those caterpillars inside to assure they have the best chance of completing their life cycle. You can feed them milkweed leaves and keep them in a clean container, then relocate the chrysalises once they’ve formed.
Learn more about rearing Monarch butterfly caterpillars at the Monarch Watch website.
Those of us who raise caterpillars in our kitchens and gardens have been known to use pins, tape, glue, fishing line–and dental floss, my favorite–to fasten chrysalises to twigs, coffee stirrers, chopsticks, potted plants, even the kitchen cabinet.
Why do we do it? To ensure their completion of the life cycle is one reason. But it’s also one of the most rewarding aspects of “butterflying.” To witness eclosure, the moments surrounding a butterfly’s emergence from its chrysalis, is always magical. The only way to do that is to have the chrysalis in captivity, where you can monitor its progress and not miss the miracle of metamorphosis.
When relocating a chrysalis, keep in mind:
1. Putting them in direct sun–a hot window, for example–can damage their development. A bright, protected spot is best. 2. Monarchs and other species need to hang vertically so that when they eclose, gravity can assist in their wings forming properly. Swallowtails are different. Try to emulate the chrysalis’ natural positioning as much as possible. 3. Once the butterfly emerges, it needs several hours before it can fly. If you’ve brought it in the house to watch, leave the newborn alone until its wings harden up and it starts beating them slowly. Then you can release it outside.
An excellent resource for relocating chrysalises and reattaching them without causing harm is Shady Oak Butterfly Farm. Edith Smith, butterfly meistress, and a member of the International Butterfly Breeders’ Association, has been raising butterflies for decades and graciously shared the useful links below. Thank you, Edith!
1. How to move/relocate chrysalises 2. How to adhere chrysalises with glue 3. What to do if a soft chrysalis falls 4. How to reattach a swallowtail chrysalisFor more info on this topic, check out our post on How to Move a Monarch Chrysalis.