Woolly bear larva

[DR. JAMES ADAMS]

Chuck,

> This winter I started an experiment using the woolly Bear larva. It
> has been long know that the marking of the larva are not always
> divided into thirds. This has led to the predicting of mild or harsh
> winters.

Interestingly, there may be a *little* truth in the predictive value of 
the darker versus lighter Banded Woolly Bear moth (Pyrrharctia 
isabella).  Cold temperatures apparently have *some* affect on 
deposition of more melanin in the larvae of the *following* 
generation of the moth.  Which means that a cool summer could 
lead to darker larvae in the fall, and a cold winter could lead to 
darker larvae in the spring.  Now, assuming that a cool summer is 
likely to be followed by a cool winter, or, more likely from a 
climatological standpoint, back to back years are similar in their 
temperature regimes, then I suppose you could suggest that there 
is a little predictive value in the coloration of the Banded Woolly 
Bear.  It is true that sequential years are more like each 
temperature-wise than years separated by decades (for instance, 
we had several mild-winter years in a row here), but this year was a 
transition year, with a cooler winter.

	However, the width of the reddish and blackish bands has a 
*major* genetic component.  I've seen larvae that are nearly all red, 
and some that are majorly black (though not ever entirely black) in 
the same brood, so there is also a lot of *variability* in the alleles 
for this trait.

> What I would like to know is if the markings in some way produce
> variations in the adults? 

The coloration of the bands has been shown to be completely 
independent of adult coloration.  I believe this is true for virtually 
*any * species (though I won't say all) of lep for which the basic 
genetics of larval and adult coloration have been worked out.

> I now have two woolly bear larva that do not have the standard
> markings. 

Please be aware that the family of moths that the BAnded Woolly 
Bear is in has many different species in it, most of which are 
indeed "woolly bears".  Many are solidly black with various 
longitudinal lines of white, yellow, or red.  Others are black with 
white, orange or red intersegmental grooves. Etc., etc., etc. . . 

	So, unless you are familiar with the different species, I don't 
know that you will find out anything from your larvae, especially 
since many species overwinter as diapausing larvae, and they can 
be a bi___ to get through to the adult stages!

	James

Dr. James K. Adams
Dept. of Natural Science and Math
Dalton State College
213 N. College Drive
Dalton, GA  30720
Phone: (706)272-4427; fax: (706)272-2533
U of Michigan's President James Angell's 
  Secret of Success: "Grow antennae, not horns"

 
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