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 | Paper Wasp
- Polistes dominulus
This invasive species has caused great
commotion amongst birders and other naturalists. It appears to be
rapidly replacing the common native paper wasp
Polistes fuscatus.
Live adult wasps photographed in the wild at DuPage
County, Illinois, USA.
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This species was accidentally introduced into North
America from Europe and has been spreading
throughout the U.S. There has been a great flap
among those who promote the purple
martin and other bird species by
building and maintaining bird houses; it
has been said these wasps are more aggressive
than the native variety, and greatly
appreciate the environment inside such
(wooden) structures.
Whether the species is aggressive has
not been established; neither is the
assertion they are harming native
species (butterflies are most-often
mentioned). As in many cases of internet
hyperbole, a single article seems to be
the source of numerous erroneous or
unsupported assertions. In the case of
P. dominulus, this article is the
Penn State College of Agriculture
diatribe. In it, the author offers
no evidence to support any of his
claims, but rather offers vague
pronouncements such as "The increased
risk for stings is an obvious concern"
and "Some entomologists worry"
the wasps are adversely affecting
butterfly populations. (What
butterflies? What entomologists? Why do
they think that?) The article in
Wikipedia parrots much of the
nonsense in the Penn State article. (Why
doesn't that surprise us?) The Wikipedia
article even goes so far as to assert "
The Penn State article goes on to advise
(homeowners) to "make every attempt" at
eliminating the nests, going so far as
to claim "It is easy to knock down
exposed nests and kill the queen."
(This, after claiming the additional
danger posed by the wasps is because
they nest in enclosed, hidden spaces).
The article also advises the use of
"wasp and hornet sprays (that) produce a
stream of insecticides that can shoot up
to 20 feet from the nozzle." Oh, don't
forget: you're supposed to spray the
nests at night. Just what we need - more
idiots running around spewing
insecticides.
I can tell you from experience: these
wasps will studiously ignore you under
every circumstance unless you blunder
into or purposely attack their nest. I
have been inches from hundreds of wasps
and dozens of nests, and I have never
been stung or attacked or even noticed.
The dangers posed by these creatures are
overblown, and claims they hurt native
species are unsupported.
I have noticed Polistes dominulus
does not appear as susceptible to
infestation by
Strepsiptera,
the endoparasitic "twisted-wing"
parasites. I frequently see
P. fuscatus infected, but
never P. dominulus. |
Wasps that construct
nests made of a papery material are commonly called paper wasps. The
nests consist of a single upside-down layer of brood cells. There
are 22 species of paper wasps in North America and about 700 species
world-wide. Most are resident in the tropics of the western
hemisphere. The two most common paper wasps in the American midwest
are Polistes dominulus, an introduced species, and Polistes fuscatus,
the native "golden paper wasp." It is my opinion, after 5 years of
careful field work and observance, that dominulus is replacing
fuscatus, at least in the environs of DuPage County, Illinois.
Most paper wasps measure about 2 cm (0.75 in) long and are black,
brown, or reddish in color with yellow markings. Paper wasps will
defend their nest if attacked. Adults forage for nectar, their
source of energy, and for caterpillars to feed the larvae (young).
They are natural enemies of many garden insect pests.
The nests of most species are suspended from a single, central
stalk, or pedicle, and have the shape of an upside-down umbrella.
Some tropical species make nests that hang in a vertical sheet of
cells. Plant and wood fibers are collected by the wasps, mixed with
saliva, and chewed into a paper-like material that is formed into
the thin cells of the nest. The nests are constructed in protected
places, such as under the eaves of buildings or in dense vegetation.
The nest pictured here was constructed under the iron railing of a
bridge over the DuPage River West Branch. Normally a colony of
several to several dozen paper wasps inhabit the nest.
The colony is founded in early spring, soon after the queens emerge
from hibernation. As the colony matures, males and the next year's
queens are produced. These queens mate with males and are the only
members of the colony to survive through winter. In late summer or
fall, the founding queen, workers (sterile females), and males all
die. The newly mated queens hibernate, in piles of wood, in
vegetation, or in holes. The following spring they emerge and begin
the cycle anew. A similar life cycle is found in bumble bees.
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The hexagonal structure of the brood cells is apparent in this
wasp's nest made of "paper" - chewed up plant tissue and saliva.
Wasps Versus
Drug Smugglers
According to Discover Magazine, the antennae
of common wasps are as sensitive to smell as the nose of
drug-sniffing dogs used by the United States Drug Enforcement Agency
(DEA). Scientists at the University of Georgia at Tifton have
invented a gadget that takes advantage of the wasps ability to sniff
out odors such as those emitted by corpses, drugs, bombs or toxins.
It's called The Wasp Hound: a canister the size of an ordinary soda
can, containing insects trained via classical conditioning to
associate a certain odor with food (a simple sugar syrup).
When the wasps in the Wasp Hound canister detect the chemical odor
they are trained for, they cluster around the source. A minicam
inside detects the wasps' movements and transmits the results to a
laptop computer.
The scientists point out the advantages of
insect sniffers over our canine pals: The wasps are small and
portable, and the training only takes 5 - 10 minutes. They don't eat
much, and nobody gets attached to the darned things. They die after
48 hours, but they just insert a new batch and the device is again
ready for action. They claim the wasps can be trained to recognize
most chemicals.
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