by Bill Oehlke
In my late preteens I had a large number of walnut sphinx larvae that reached maturity in a sleeve on ironwood. I had read that they needed a soil medium for pupation, and it had been my good intention to fashion some sort of wooden frame to house whatever mixture I could concoct.
Unsure of myself, I read, several times, suggestions/instructions for constructing and filling a frame. Still lacking confidence, I procrastinated and put off what really should not have been a monumental task.
The larvae progressed rapidly and I soon found them "stumpy" and inactive in the frass at the bottom of the sleeve.
I felt guilty, not having prepared a pupation bed in advance, and was sure I had killed most of them. I released those still moving and emptied the sleeve, thus ending my first attempt at rearing Sphingidae.
I didn't try again for another forty years.
I happened to collect a female Pachysphinx modesta at my mercury vapour light atop my roof and read again, perhaps in Villiard's Moths and How to Rear Them, the "necessities" for the earth pupators.
I started early and fashioned a three foot square frame out of 2" x 6" lumber, put some screening on the bottom, a layer or two of remay cloth on top of that and was about to fill the chamber with loose soil in its rightful place when by chance I had an email "converation" with an English rearer who shared a much simpler technique.
No soil is necessary. The Sphingidae and Ceratocampinae (our famous regal moths: imperialis, regalis, etc.) will all pupate in a dark cell/chamber/container devoid of any earth.
This information came just in time. Some of the modesta larvae had reached maturity inside the large remay sleeve over a poplar branch and had actually chewed through the material so they could escape and descend the tree.
The bulk of them, however, were either still feeding or crawling on the sleeve material looking for a way out.
I learned a few things:
1) Mature earth pupators (at least the ones that are going to overwinter) often take on a darker colouration just prior to pupation. The modesta had a pinkish cast to their skins. Darapsa choerilon become a rosy brown.
2) Mature earth pupators leave the foliage to crawl around on sleeve material or descend to the base of the thickest stem.
Over the years I have learned a bit more and now do the following to tend to the earth pupators at pupation time.
1) I generally remove the almost full grown larvae
from their outdoor sleeves when they are nearly mature. This requires
just a bit of experience, but if you watch/inspect your sleeves
regularly and note the "look" and size of larvae when they start to
leave the foliage, you'll soon have the experience you need.
2) Mature or almost mature larvae are brought indoors to large, clear
plastic tubs anywhere from two to twenty gallon size. Cut foliage
is put into the tubs (lids on tight no air holes) with the larvae.
As soon as I see larvae crawling around on tubs instead of on
foliage, I move those larvae to (empty, no foliage) buckets or tubs (any old plastic
container will do) lined with a few layers of loose paper towels on
the bottom.
It probably makes the larvae feel a bit more "natural" if the pupation buckets are kept in a dark place, but I've had larvae pupate under towelling in clear plastic tubs on the kitchen table.
You might feel a bit apprehensive the first time you try this as the larvae seem to shrivel quite a bit, and their legs get very stumpy so they can no longer walk. This just means pupation is imminent.
My Sphingidae usually pupate in four to five days after being placed in the pupation container.
It is very important not to handle pupae until they have hardened for several days as they are very tender initially and easily damaged. I would wait at least 4-5 days, maybe even a week before moving/handling them.
Once the puape have hardened, they can be stored as per instructions in overwintering cocoons and pupae.
I have been asked how long one should wait before removing pupae that have pupated underground. I would wait at least one week from disappearance date, maybe even two weeks just to make sure pupal shells have hardened.
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