James J. Kruse kruse at
Wed May 28 13:16:50 EDT 1997

On Sun, 25 May 1997, robert thorn wrote:

> All of this talk about 'sugaring' has triggered my scientific curiosity.
> Does anyone know what ingredients of the common
> "sugar/molasses/beer/banana" mix actually attract the moths from afar?  If
> you alter or eliminate different ingredients, does that affect the species
> composition that comes to the bait?  It would appear from many of the
> mailings that certain species are keyed in to components of dung aroma, but
> are there other species that key on fermenting sap or rotting fruit (given
> the significant number of Spring or Fall moths that might use these as
> major food cues)?
>                                         Rob Thorn,  thorn.5 at
I would say that for some moths it is the sweetness, and others it is the
fermentation.  While maple sugaring in the early spring in Wisconsin, I
noticed many moths coming to the buckets and wounded trees during the
night.  Also, I have seen butterflies and moths coming to rotting fruit at
our little compost heap when I was growing up.  Bait seems to work best in
the early spring until the trees bloom, and again in early-July through
the late fall.  I think most of the attendees are residents of the
adjacent woods, with an occasional stray that happens to be in the

My ingredient altering has been rather limited (always a sugar, a fruit,
and something alcoholic).  I do know that you won't usually see the same
species at the above bait and also at dung (though I have seen some
Nymphalis spp at both).  I think a lot depends on the year also.  There
have been years where I am lucky to find 10 species in a week, and some
years where 10 species per tree gets boring.  A lot probably depends on
the presence of natural foods.  One night I came across a wounded oak tree
that had a diverse crowd of moths feeding at it, whereas my bait on nearby
trees was scarcely attracting anything.

Hope this helps!
Jim Kruse
University of California at Berkeley
Dept. of Environ Sci, Policy and Mgmt.
Div. of Insect Biology
Sperling Lab
201 Wellman Hall
Berkeley, California, 94720-3113
(510) 642-5114

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