Monarchs on the move? Sometimes a little lift is required for health and safety in the garden (and beyond). Supporting the caterpillar stage of life is a big part of monarch gardening. We’ve expanded caterpillar hosting and helping segment of the mini-series to break out more detail on hosting, including moving and relocating monarch caterpillars.
Why Monarch Caterpillars May Need to be Moved
In our garden, we use netting to protect caterpillars from paper wasps, but this also blocks butterflies from laying eggs. Either eggs or caterpillars need to be moved under cover. This is our most common reason for moving caterpillars.
Caterpillars may also need to be moved due to environmental hazards, plant care and pruning, sharing caterpillars with friends/neighbours who have lonely swan plants and impatient kiddies (or grown ups!), rescuing hungry caterpillars from nibbled nubs, or other special circumstances.
Safety Considerations During Caterpillar Movement
When transporting caterpillars, my aim is to never touch them. They can, with care, be handled, but it’s safer and less stressful for both of us to avoid direct handling. Small young caterpillars are particularly delicate for handling. I think its best practice to minimise handling at all stages of development.
Chemicals and Contaminants
Even with no contact as the aim, it’s best to ensure that hands, gloves, and anything else in close proximity is clean and free of any potentially harmful chemicals that could accidentally harm the caterpillars.
Ideally, caterpillars are moved on a large cutting or with mobile plants. They can keep nibbling on the current host plant and slowly make their transition to their new host plant. For practicality when frequently moving caterpillars over short distances, something more efficient is often needed. That’s when I use to individual leaves or small cuttings for transport.
Molting or freshly molted caterpillars should not be moved. Caterpillars uses their silk to secure the current skin in-situ so that, when ready, they can walk itself out wearing the new skin beneath. If a caterpillar seems unwilling to move its rear (anal prolegs), leave it alone. Immediately after the molt, the newly exposed skin is soft and the caterpillar is particularly vulnerable.
Caterpillars who have gone into their dangling J in preparation for forming a chrysalis should not be disturbed, if possible. They may not be able to reattach, which leads to and early death instead of ongoing transformation.
Moving Caterpillars Over Short Distances
To avoid touching, I use a leaf or small stem as a short-distance caterpillar carrier. We jokingly refer to it as catching an Uber. I prefer this method to using my hands or something like a paintbrush, since moving on a leaf causes as little contact and disturbance to the caterpillar as I can manage.
Where possible, I use the leaf that the caterpillar is already on. I cut or pinch it from the plant, then carry it and its caterpillar passenger to the new plant. They’re pretty good at holding on, but I still like to keep a safety hand underneath the carrying hand, just in case!
At the destination, I either hold the leaf on the new plant and wait until the caterpillar strolls off or carefully leave it at the base of the new plant. The latter is most convenient, but I sometimes prefer waiting just to be sure the transfer is safely completed.
Moving Caterpillars Over Longer Transits
For slightly further transits, larger cuttings in a jar of water or potted swan plants make good carriers. Caterpillars can be transferred from elsewhere onto the cutting or plant before transit, if needed.