Rain Moth Pupa from Australia

Subject:  What’s this thing
Geographic location of the bug:  Melbourne, Australia
Date: 03/30/2018
Time: 02:39 AM EDT
Your letter to the bugman:  We found this moving in and out of a hole in the ground.
It’s about 10cm long, and almost 2cm in diameter.
How you want your letter signed:  Sandford Family

Rain Moth Pupa

Dear Sanford Family,
This is a moth pupa, and that of quite a large moth.  We believe we have correctly identified it as a Rain Moth Pupa,
Trictena atripalpis, thanks to an image on Butterfly House where it states:  “The caterpillars of this particular species live in tunnels in the ground where they feed on the roots of adjacent Australian native trees” including red gum.  The site also indicates:  “The moths a famous for being able to predict rain. In some areas in autumn, the moths appear on only one night each year, yet all appear together in droves, and always just a few hours before a major downpour in that area. Perhaps the rain helps wash the scattered eggs into crevices in the ground, as well as dormant seeds to germinate, so that after the eggs hatch: the young caterpillars can easily find roots on which to feed.”  That causes us to wonder if perhaps the sighting coincided with rain.  Additional images can be found on Insects of Tasmania where it states:  ” The Hepialid larvae live in silk lined holes and come out at night to feed. They then pupate in the hole.  Trictena atripalpis often leave their pupal case half out of their exit hole.”  We suspect that by the time you get this message, the adult moth might have already emerged from the pupa.

Rain Moth Pupa
Thanks heaps for your reply.
You certainly pinpointed it.
It hatched a day later, however but no rain was in sight. Perhaps we had disturbed it’s nature cycle.
However we did take a time-lapse of it one night after it had hatched where you can see it laying eggs.
I’ll send you a link once we’ve uploaded it.
The Sandford Family.
Rain Moth Pupa

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