Butterfly-predacious hornets

[Kenelm Philip]

	J.W. said:

> ...some attention may be given to how to discourage hornets from
> taking butterflies from backyard buttryfly bushes,  or how to educate
> them on the displeasure they cause the bush owner.

Yellowjackets play a largely beneficial role (from a human perspective),
devouring a number of pest species. They can indeed also have an effect
on butterflies (usually by taking the larvae). A yellowjacket outbreak
in the Fairbanks, Alaska area in 1994 reduced the populations of most
taiga butterflies down to 1% to 2% of their 'normal' numbers, and the
recovery took about 2 years. Yellowjacket numbers tend to fluctuate a
lot from year to year--so they will usually not persist at high levels
for years at a time.

	If large nests on your house are resulting in stings to occupants,
one should try removing the nests. Aside from that, it is best to leave
yellowjackets alone. As far as their eating butterflies goes, it may be
some consolation to realize that predation plays an important role in
natural selection, and evolution. So in the long run the yellowjackets
are probably doing more good than harm to butterflies.

							Ken Philip
fnkwp at aurora.alaska.edu