Friday, August 16, 2013

Eight-spotted Foresters Pupate

Eight-spotted forester moth- Shelly Cox, Mobugs.com
We discussed the eight-spotted forester moth, Alypia octomaculata, in a recent blog.  Roy Thompson had found them on a grapevine and took them home to raise them in a predator free environment.  Roy has a followup report on the outcome.

Preparing to pupate-Roy Thompson
The caterpillars have one special request before their last instars pupate - they require a nice soft bed to curl up in for the winter.  They normally use rotting soft wood to burrow into and are said to have learned to use styrofoam in the age of plastic.  Roy gave his caterpillars wood and foam insulation.

His caterpillars were apparently very conservative traditionalists as they spurned the softer insulation and bored into the wood.  After each cat dug in, it sealed up the hole with a wood like substance, leaving only a little crack (see the arrow).



After giving them time to pupate, Roy unroofed the wood from over one pupa's chamber as seen below.  It was tightly nestled in, safe from many predators although it would be easy pickings for a woodpecker.




They overwinter in these chambers then emerge from their pupae (think cocoon) around May and may be seen all summer.  In southern climes they may have two generations a year or even three occasionally.  Some that have overwintered may postpone emerging for several years, a feat called diapause which is found in some other moth and insect species.
"The timing of their emergence from the pupal case can be capricious. In 1977, an entomologist raised 80 caterpillars and ultimately got 50 pupae that he stored in a box at outside temperatures. Nine adults emerged in the spring of 1978; twenty-five emerged in 1979; four appeared in 1980 and one more the following year. So EsFMs, like a number of other moths in a variety of families, have the ability to remain in diapause (dormancy, a state of suspended animation during which development is delayed) for a considerable length of time. What triggers their exit is unknown." University of Wisconsin, Milwaukee
  Shelly Cox
The eight-spotted forester moth is a beauty, a dramatic black with two pale yellow spots on the fore wings and two white spots on the hind wings.  There are bright orange markings on its two pair of front legs which Shelly at MoBUGS.com says reminds her of leg warmers popular in the 1980's.  Some think that these may serve to mimic a bee's pollen-laden legs.

As you can tell by the pictures, these are day-flying moths, and thus are frequently misidentified as butterflies.  Their thin antennae cause further confusion, lacking both the moth's typical feathered antennae and the knobs at the end of butterflies.

In recent years, humans have developed techniques for planned delivery of babies, but even we haven't figured out how to postpone the delivery for several years.  Mother Nature wins again.

There is a nice set of photographs of the eight spotted forester at aprairiehaven.com.

Gala Solari sent this picture.  Is it animal? Plant?  Geological?  An empty cupcake paper?

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