FW: FW: What happened to our biggest moths?

[Mike Quinn]

-----Original Message-----
From: Jeff Boettner [mailto:boettner at ent.umass.edu] 
Sent: Thursday, April 19, 2001 11:03 PM
To: Mike Quinn
Subject: Re: FW: What happened to our biggest moths?


Dear Mike,
    I have been in the field for 10 days and so sorry for the slow response.
    Actually a tough question.  There is some pretty good evidence that
Compsilura had some effect on gypsy moth at moderate densities.  Juli Gould
in our lab did a neat study ( 1990 Journal of Animal Ecology 59:pages
213-233) on this subject using gypsy moth releases of different densities
( 40,000-1 million gypsy moths per ha.) and found that Compsilura was acting
in a density dependant mannor ( ie over 90% mortality of the biggest gypsy
moth releases).  All of her artificial plots were completely wiped out by a
sweet of flies, wasps and beetles.   So it likely that the fly does delay
the time between outbreaks.  I am working on another pest (browntail moth)
which the fly was also released to control and this may have worked
incredibly well...almost drove it to extinction...we hope to have a paper on
this within a year or so.
    As for tent caterpillars...from my limited view Compsilura seems to have
no effect.  Most of the tent caterpillar tachinid flies are extreme
specialists as they have to be able to deal with the protective webs...so
they have special feet for walking on webs without getting caught...even if
they attact the cats while out of the web in feeding, the caterpillar would
likely return to the web to die and the fly is still stuck when it tries to
emerge.  We just hired a tent caterpillar specialist ( Dr. Dylan Parry) and
he has done some neat work that demonstrates the reason for what you
observe.  What seems to be important is how late the budbreak ( opening of
the buds) is.  I don't have his papers handy, but it has to do with
something like .... if the development of the caterpillar slows even a small
amount, it allows some of the later parasitoids to have a longer season and
the caterpillars get nailed, but if its an early and warm spring the
caterpillars can complete development before the parasitoids emerge...a
constant arms race.
      Back to gypsy moth, what has finally worked quite well is the species
specific fungus from Japan, Entomophaga maimaiga.  We will still have some
serious outbreaks following back to back drought years, but in western MA,
we really haven't had a big outbreak since 1981.   We have documented the
fungus is having a major effect in a few different papers.
      Hope that helps.
     Jeff

----- Original Message -----
From: Mike Quinn <Mike.Quinn at tpwd.state.tx.us>
To: George Boettner (E-mail) <boettner at ent.umass.edu>
Sent: Wednesday, April 11, 2001 6:18 PM
Subject: FW: FW: What happened to our biggest moths?


>
>
> -----Original Message-----
> From: Michael Gochfeld [mailto:gochfeld at eohsi.rutgers.edu]
> Sent: Tuesday, April 10, 2001 9:18 PM
> To: Leps-L (E-mail)
> Subject: Re: FW: What happened to our biggest moths?
>
>
> Question to Jeff Boetner or anyone else.
>
> How effective were the flies in controlling either Tent Caterpillars or
> Gypsy Moths.   Tent Caterpillars here (NJ) seem to be influenced more by
> how cold the winter gets  (not very cold in most recent years) and Gypsy
> Moths came and went and elicited heavy spraying suggesting the
> biological control was not very effective.
>
> M. Gochfeld
>

 
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