Hemileuca nuttalli

[Cris Guppy & Aud Fischer]

While your description of H. nuttallii's life-cycle in BC is accurate (pupae
overwinter), the term two year life-cyle is incorrectly applied. It is a one
year life-cycle (a univoltine species), because it takes one year to go from
adult to the next generation of adults.

A two year life-cycle (bivoltine) occurs in butterflies such as Arctics
(Oeneis species), with young larvae overwintering the first year, and mature
larvae overwintering the second year. It takes two full years to go from
adult to adult, hence it is a two year life-cycle.

I have reared nuttalii several times in BC, and have had very poor success
in getting adults to emerge. I have tried refrigerating the pupae, and they
simply died (dehydration??). I have tried storing them in the crawl space
under the house (in central BC, the crawl space stays about -5 C most of the
winter), and all the pupae lived but only 4 adults emerged from 50 pupae.
Presumably if I had the patience I could have overwintered them again, and
gotten a few more adults the next year.

Perhaps those more experienced in rearing Hemileuca can suggest how to
obtain higher more adults from the pupae.

As I was about to send this message, I realized an apparent error in the
original inquiry. Hemileuca nuttallii does not occur near Merritt, BC. Its
larval foodplant in BC is restricted to Pershia tridentata, which (in BC)
only occurs in the south Okanagan Valley and not near Merritt. If the larvae
were collected on big sagebrush (which is not stated in the original
inquiry), Artemesia tridentata, then the moth would be Hemileuca hera. H.
hera is rarely collected as an adult in BC, but apparently occurs throughout
the southern interior of BC wherever big sagebrush occurs. The life-cycle is
the same as for H. nuttallii.

As a rearing note for next year, H. nuttallii larvae are common on Pershia
along the highway near Vaseux Lake most years in May. They can be reared on
snowberry (Symphoricarpos) or ocean spray (Holodiscus), which saves the
inconvienience of trying to transport Pershia out of its native habitat.

----- Original Message -----
From: "MJS323" <mjs323 at aol.com>
To: <leps-l at lists.yale.edu>
Sent: September 20, 2000 4:23 PM
Subject: Re: Hemileuca nuttalli


> In most, if not all, of Hemileuca nuttallii's range, it is on a two year
life
> cycle.  One summer as larvae after overwintering as eggs, and the next
summer
> as adults after overwintering as pupae.  Your nuttallii pupae should
naturally
> emerge next summer, probably late July to mid August in the field.  Most
of the
> Pseudohazis group of Hemileuca (eglanterina, hera, nuttallii) are two year
> cycles in most of their range, except eglanterina does have one year
cycles in
> parts of coastal and inland California.
>
> Mike Smith
>
>