Applegater
Winter 2012 9
Notes from a Rogue entomologist:
Night of the living bedbug
BY RICHARD J. HILTON
If you read the paper or listen to
any of the mass media, you are well
aware that bedbugs are back with a
vengeance. Indeed, the bedbug population
seems to have exploded over the last
few years. Much like zombies, another
group that has seen resurgence in media
attention, they are relentless, mindless,
and their only desire is to feed on us.
Bedbugs belong to a group of
insects referred to as “true” bugs whose
mouthparts are modified to suck plant
or animal fluids. These true bugs include
plant feeders such as stinkbugs, squash
bugs, box elder (or maple) bugs, and
predators like the assassin bug. (It is worth
noting that this group does not include
ladybugs and lightning bugs, both of which
are actually beetles and not true bugs.)
The closest relatives of the common
bedbug, which prefers humans, are species
that are usually found feeding on swallows
and bats, with the bat bug being the
most similar. It would appear that when
humans began living in caves or fixed
structures of the sort that bats might
also inhabit, a “host-switch” took place
and our species acquired a new partner,
a blood brother, so to speak. On the
positive side, the bedbug has, so far, not
been connected to any transmission of
human disease. Nevertheless, there’s no
denying that bedbugs are very creepy and
no one likes to donate blood without being
asked. So we are going to have to devise
some new tactics for controlling them.
Speaking of new tactics, I got an email
a few months ago from someone checking
to see if any of the Oregon State University
(OSU) entomologists had a colony of
bedbugs that they could use to train dogs
for sniffing them out. It is well-known that
bedbugs emit a characteristic musky odor
and, with large bedbug infestations, the
smell can be very distinctive. However,
dogs can smell and locate bedbugs when
the population is still low, and they have
proven quite useful for this purpose.
Unfortunately, it is an expensive service,
mostly because the current demand for
canine supersniffers far exceeds the supply.
With the return of the bedbug,
research is booming. I attended the most
recent national entomology meeting in
Reno last November, and there were more
presentations on the bedbug than any
other insect species except the honeybee.
I ran into a Southern Oregon University
(SOU) graduate with whom I had worked
an attractant, which chemical ecologists
refer to as a kairomone. In the next phase
of his research he will try to isolate the
kairomone so it can then be used to
monitor or aid in control of bedbugs.
As to my own encounters with
bedbugs, I have had bedbugs brought
into the office on a few occasions, but
not really that many. When I get bedbugs
they are usually in pretty bad shape,
victims of insecticide spray or floating in
rubbing alcohol, but I did once receive
Bedbugs are parasitic insects that prefer to feed on human blood.
on a project concerning insect attraction
to pears. He is now pursuing a higher
degree in entomology and is working on
bedbugs. Although bedbugs were not
his first choice, that is where the research
dollars are and he was happy to oblige.
He is looking for the chemical signal that
attracts bedbugs to humans. Bedbugs are
definitely attracted by body heat, but as
they are fairly specific to humans, there
is probably a chemical that humans give
off that acts as a chemical cue. His initial
studies, using sweaty socks among other
things, indicated the existence of such
a live virgin female bedbug. If you are
wondering how I knew it was a virgin
female, well, the sex life of the bedbug
is rather odd, to say the least. The male
bedbug does not mate in the normal
manner but pierces the female’s abdomen
to deposit his sperm. This traumatic
insemination leaves a scar and my female
did not have that telltale scar. Also, despite
feeding her twice, she never laid any eggs.
I dubbed her “Betsy.” When I fed her,
I discovered that her bite was absolutely
painless and I had no adverse reaction
whatsoever. However, some people do
Hungry bedbug finds a victim.
react—out of 900 volunteers who were
subjected to bedbug feeding during a
study at Orkin’s Training Center, less than
five percent had a reaction, but there is
also evidence that the more often you are
subjected to bedbug feeding, the more
likely that a reaction will occur. The bedbug
needs a blood meal before each molt and
then prior to laying eggs. Therefore, an
individual bedbug needs to feed on a
person multiple times throughout its life.
The first time I fed Betsy, I had a little
cage on my wrist and watched intently
for quite awhile, but nothing happened.
I finally started doing something else, and
by the time I checked on her again she
was half engorged. She lived close to a year
and I do have some lingering regret about
her death from starvation. In retrospect,
I should have fed her more often and I
definitely should not have named her.
I am surprised at the number of
people I encounter who seem truly fearful
that their homes could be infested by
bedbugs. Admittedly, it is an alarming
prospect not just because bedbugs are
difficult to get rid of, but also because
they have traditionally been associated
with “unclean” environments. That
stigma has diminished somewhat now
that bedbugs have been discovered in
penthouses as well as flophouses. However,
as long as the bedbug population is on
the rise, research to understand our
parasitic bedmate will continue as we
try to return to a time when “don’t let
the bedbugs bite” was said only in jest.
Richard J. Hilton
541-772-5165 ext. 227
Senior Research Assistant / Entomologist
Oregon State University
Southern Oregon Research and
Extension Center
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