Timing emergence for Saturniidae

Robert Kriegel kriegelr at pilot.msu.edu
Wed Aug 11 09:56:22 EDT 1999

This is a response to Bill Welch's question about delaying adult emergence.

While volunteering at the butterfly house here at Michigan State University
I did an experiment with monarchs and zebra butterflies.  We were
attempting to even out boom-and-bust adult emergences of these two species
used in the free flight room.  

Newly formed pupae were placed in a growth chamber at 10 C (50 F) for
various lengths of time to see if we could delay emergence.  As you would
expect the zebras did not do very well at this cool temperature; many
adults either did not eclose successfully or were deformed.  However, the
process worked very well with monarchs.  I was able to hold monarch pupae
at this temperaure for up to three or sometimes four weeks before moving
them to room temperature to emerge.  As long as the pupae were still green
when I removed them from the cool chamber they eclosed without difficulty.
However, if a pupa had already turned dark before it was moved, the adult
often had problems either eclosing or inflating its wings.  

My limited experience getting adults to emerge from wild saturniid cocoons
suggests that these creatures are not nearly as predictable as the monarchs
were.   However, you might try keeping them cold long enough to complete
their overwintering requirement then bring the cocoons out into room
temperature in small weekly batches.  Misting the cocoons might help
trigger a more timely emergence.

Bob Kriegel  <kriegelr at pilot.msu.edu>
systems analyst, Dept. of Naimal Science
Michigan State University

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