moth behaviour

[David R. Britton]

In article <199705292143.RAA03015 at comet.connix.com>, jhimmel at CONNIX.COM wrote:

> Hi LEPsers -
>
> I have come across a number of moth species, most often in the subfamily
> Plusiinae (Loopers) and some of the Zales, that rest with either a
single tuftof
> scales, or several tufts erected from their upper thorax.  Does anyone know
if
> this has something to do with pheromone release?  Incidentally, they
tend to be
> very docile when in this position and may stay in the same place for days.
>
>                 tuft
>                  \\ _________
>   side view     O( )________\\
>      of moth   __/| \__
>                  /
>
>
> Thanks in advance for any insight.

John,

I don't know if this counts as "insight" but I always assumed that this
crest was just to break up the outline of the moth when it was resting
against natural substrates like tree trunks etc, and hence improve the
camoflage.  Without the crest, the straight line formed by the wings in
the resting position might be easier for a predator to locate.  I cannot
see it being used for pheromone dispersal, because it is present in both
sexes (at least in Chrysodeixis argentifera which is the only species I
have had much experience with in the Plusiinae).  These crests are also
common in the Geometridae and the Notodontidae in particular, presumably
for the same purpose

cheers,

Dave B.

--
David R. Britton, Biological Sciences, University of Wollongong
Wollongong, NSW, Australia, 2522.
Ph.(61-42) 21 3436,Fax.(61-42) 21 4135