A question regarding Hawk moths

[Roger C. KENDRICK]

jmarsano at worldnet.att.net wrote:
.....
> I have a question about Hawk moths.  I recently read in
> Gilbert Waldbauer's _Insects through the seasons_
> that it has been hypothesized that some species of
> Hawk moth might have developed a 'jamming' technique
> to defeat the echolocation clicks of predator bats.
> 
> This book was published in '96 and I'm wondering if
> any experimental results since confirm or negate this
> hypothesis.  Has anyone here heard about it?
It is well known in tiger moths (Arctiidae), e.g. Arctia caja, but I've
not knowingly heard about the jamming of bat echolocation sonar by
Sphingidae.

> If true, do you think that this 'active' jamming
> (whereby the moth is emitting sound) would be more
> energy-intensive than an evolutionary strategy which
> covered the moth in sound-absorbing 'baffles?  This
> might not be a correct analogy, but we use 'passive'
> design techniques to cloak submarines, ships, and
> aircraft from surveillance and tracking radar and sonar.
> (Soviet submarines, for example, were protected from
> active 'pinging' sonar, by being covered with anechoic
> rubber tiles.  Or at least that was the idea.  I've never read
> in any authoritative source that they were effective, or
> useless.)
I'd guess that having lots of dense scales on the body (as most
Sphingidae do) _may_ help deflect sound waves away from the source, but
this is pure conjecture. Baffles - in the sense of those used to absorb
sound in quiet rooms (such as some recording studios) - would probably
render a moth aerodynamically inefficient.

Anyone else have any ideas?

Roger.
________________________________________________
Roger C. KENDRICK   B.Sc.(Hons.)
PhD student & Demonstrator, Dept of Ecology & Biodiversity
The University of Hong Kong
mailto:kendrick at hkusua.hku.hk
http://web.hku.hk/~kendrick/hkmoth.htm   « Hong Kong Moths »
http://www.geocities.com/RainForest/Canopy/1085/   « H.K. Lepidoptera
Group »
mail: Kadoorie Agricultural Research Centre
      The University of Hong Kong
      Lam Kam Road, Shek Kong,
      Yuen Long, New Territories
      Hong Kong
fax: (852) 24885285
=================================================