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BED BUG
SUPPLEMENT
Bed bugs are “top of mind” these
days for most pest management
professionals. Consumers have
also become “edgy” — to the
point where any questionable-looking
bug spotted in a bedroom, hotel room,
etc., could potentially be a bed bug. With
such unease, it’s understandable why
similar looking pests might be a source of
confusion. Such is the case with bat bugs
and bird bugs, the topic of this article.
In a recent survey of pest manage-
ment fi rms conducted by Insight Express
for PCT magazine, about one in fi ve re-
spondents (21 percent) said they noticed
an increase in bat bugs in recent years,
while 11 percent said the same about bird
bugs. Of those reporting an increase, 59
percent felt it was due to more bat and
bird infestations within buildings; 41
percent attributed the increase to height-
ened awareness of pests believed to be
bed bugs.
Whatever the reason, at times it will be
necessary to distinguish between these
pests and develop an appropriate course
of action.
ALL IN THE FAMILY. Bed bugs, bat bugs
and bird bugs have many similarities. All
are classifi ed in the insect family Cimici-
dae, comprised of about 100 species, 16
occurring in North America. Cimicids are
small, fl attened, fl ightless parasites that
feed solely on the blood of birds and mam-
mals. Most species live within bat roosts
or bird nests; only a few have adapted to
HOLY
COW…
Bat Bugs
and
Bird Bugs!
By Michael F. Potter, Kenneth F. Haynes, Jennifer Gordon,
Erich Hardebeck, and Eric Arnold
Bed bugs,
bat bugs and
bird bugs are
strikingly similar
in appearance.
Distinguishing
them and
knowing their
habits is now
an industry
imperative.
Fig. 1: Bat bugs (below) have longer,
more noticeable hairs than bed bugs
(right). Note especially the di erence
in hair length along margins of the
body.
Has your company noticed an in-
crease in bat bugs in recent years?
Has your company noticed an in-
crease in bird bugs in recent years?
Source: PCT/Insight Express survey January 2013
79% 89%
NO NO
YES
YES
21%
11%
72 /// AUGUST 2013 WWW.PCTONLINE.COM
BED BUG
SUPPLEMENT
the blood and beds of humans. Bed bugs
probably evolved from a bat bug long ago
when both forms fed on bats. Eventually
the bugs started biting humans inhabiting
the same caves. Tellingly, bed bugs still re-
side in bat roosts within buildings in cen-
tral Europe. Recent genetic studies have
shown, however, that bats were not a res-
ervoir for the current bed bug resurgence.
All species of cimicids have similar life
stages (eggs, nymphs, adults) and mate
via traumatic insemination — an unusual
form of mating where males pierce the
female’s abdominal wall and inject sperm
into the body instead of through the geni-
tal tract. Many cimicids have a primary
host, but will feed on other warm-blooded
animals if the need and opportunity aris-
es. The common bed bug, Cimex lectular-
ius, mostly feeds on humans but can also
persist on bats, birds and rodents. Bed
bugs also will bite dogs and cats provided
they can penetrate the fur. Unlike many
species of fl eas, lice, and mites, cimicids
normally reside off their hosts, climbing
aboard briefl y only to feed. Soon after
engorgement, they scurry away to hid-
den locations to digest, molt, mate, and
lay eggs. Cimicids ingest large volumes of
blood (often triple their body weight) in
a short period of time. Along with other
adaptations, this helps them withstand
intermittent feeding opportunities.
RECOGNITION. Distinguishing between
bed bugs, bat bugs and bird bugs is im-
portant because their hosts and habits are
different. Cimicids look much the same
— identifying specimens to species can
be diffi cult at times even for entomolo-
gists. In our recent survey of pest control
companies, more than two-thirds of re-
spondent felt that it was “very diffi cult”
(16%) or “somewhat diffi cult” (52%) for
their employees to distinguish between
bed bugs, bat bugs and bird bugs.
With a few tips and tools this can be
overcome. Magnifi cation is needed to see
features delineating one group from an-
other. A microscope is optimal, but with
a bit practice a 10-15x hand lens is suf-
fi cient for use in the fi eld. High-quality,
durable hand lenses cost about $15, but
satisfactory ones can be had for as little as
$1.50. A good source of affordable hand
lenses and microscopes is BioQuip (www.
bioquip.com), a California-based supplier
of entomological books, supplies and
equipment.
Illustrations and diagnostic keys (such
as those in the Mallis Handbook of Pest
Control) are helpful, but nothing beats
having actual specimens for comparison.
When bat bugs or bird bugs are encoun-
tered, retain some in a vial for future
reference. The location within a building
where cimicids are found also provides
clues to their identity. Bat bugs and bird
bugs seldom congregate on beds, couches,
and recliners in the manner of bed bugs.
Rather, specimens tend to be found here
and there, especially in upper rooms near
attics, etc., where the bugs’ preferred ani-
mal hosts are located.
BAT BUGS. Bat bugs are common para-
sites of bats worldwide. Apart from bed
bugs, they’re the most oft-encountered
cimicids in buildings. Seven species of
bat bugs occur in the United States. The
predominant one in the eastern half of
the country (eastward from Colorado) is
Cimex adjunctus, the eastern bat bug. The
western bat bug, Cimex pilosellus, is most
prevalent from British Columbia south to
California and Arizona and as far east as
Nebraska. These and other bat bug spe-
cies are distinguishable from bed bugs by
the presence of longer hairs or bristles along
margins of the body (Fig. 1). Hairs on the
pronotum (the shield-like structure be-
hind the head) of bed bugs are shorter
than the width of each eye, whereas on
bat bugs the hairs tend to be equal or lon-
ger than eye width. Another more subtle
difference is that the femurs on the hind
legs of bat bugs are somewhat wider than
those of bed bugs. Unlike fl eas and lice,
cimicids have no obvious adaptations for
clinging to their wild hosts during fl ight.
It’s been postulated that the somewhat
stouter hind legs of bat bugs help them
cling to the membranous wings of bats
during sudden sorties through the night
sky. Being transported about by humans
(on bedrolls, backpacks, etc.) presumably
requires less leg strength and could ex-
plain why the legs of bed bugs are some-
what longer and more slender.
Bat bugs are occasionally seen clinging
to the skin of bats. We observed this last
summer in an outbuilding when a juve-
nile bat fell from the roost. The bugs were
affi xed to the wings and required con-
siderable effort to dislodge, not unlike a
tick (Fig. 2). We’ve also noticed that bed
bugs and bat bugs respond differently to
stimulation. When bed bugs are probed
or otherwise disturbed, they move rap-
idly and erratically, clinging to surfaces.
Conversely, the slightest disturbance of
bat bugs causes them to drop instantly
from the substrate, become immobile and
retract their legs as if dead. We specu-
How di cult is it for your employees
to correctly distinguish bat bugs and
bird bugs from bed bugs?
Source: PCT/Insight Express survey January 2013
Fig. 2. Bat bugs a xed to the wings of a
young bat. The juvenile fell from the roost
moments before the picture was taken.
Very di cult
Somewhat
di cult
Not at all di cult
52%
32%
16%
Fig. 3: Bat bugs aggregate much the same as
bed bugs. These were found in a bat-infested
tool barn.
WWW.PCTONLINE.COM AUGUST 2013 /// 73
BED BUG
SUPPLEMENT
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late this behavior may be an adaptation
to avoid predation or lethal grooming by
insectivorous bats. The refl exive behav-
ior might also help to avoid sudden rides
aboard bats at night.
Communal species such as the little
brown bat and big brown bat rear their
young in maternity (nursery) colonies.
Within buildings this usually involves
attics, walls and roof cavities. Bat bug
numbers are generally highest in late-
spring and summer when bats rear their
young. Bed bugs multiply most quickly at
about 86°F, whereas 95°F is optimal for
bat bugs. Some scientists speculate that
the ability of bat bugs to thrive at higher
temperatures is an adaptation to living in
warm locations in summer. Neither bed
bugs nor bat bugs can tolerate tempera-
tures above about 113°F — so then how
do bat bugs survive in hot summer attics?
As true of other attic-dwellers (drywood
termites, brown recluse spiders, silver-
fi sh, etc.), bat bugs utilize microhabitats
that are more moderate. Temperature
readings taken in active bat roosts, for ex-
ample, seldom exceeded 103°F.
Bat bugs aggregate in bat roosts in a
manner similar to bed bugs (Fig. 3). In
such areas the bugs are often seen crawl-
ing over surfaces and accumulations of
guano. As populations build, the parasites
infl ict stress on bat colonies, especially
the fl ightless pups unable to leave the
roost. Studies have shown that one reason
communal bats vacate roosts is to lessen
their load of bat bugs and other external
parasites (e.g., fl ies, mites, ticks). Roost
switching denies parasites sustenance
and diminishes their numbers, enabling
bats to re-colonize vacated roosts in the
future. Bats can also leave bat bugs and
other parasites behind by changing to an-
other roosting location within a building.
The likelihood of bat bugs increases in
the presence of large roosting colonies
(Fig 6). Based on hundreds of inspec-
tions performed by one of the authors
(E. Arnold, Wildlife Control Technology,
Sharon Center, OH), when bats num-
bered in the hundreds — bat bugs were
noticed about 25 to 50 percent of the
time. On jobs with fewer than 20 bats, the
bugs were noted less than 10 percent of
the time. Field observations also suggest
that bat bugs seldom invade living areas
of buildings while bats are still present;
(Fig. 4) Swallow bugs (left) have long pale hairs.
Enormous populations may be present in the
mud nests of their hosts. (Fig. 5) Chimney swift
bugs (right) are small and have fewer distinct
hairs than bat bugs and bed bugs.
74 /// AUGUST 2013 WWW.PCTONLINE.COM
BED BUG
SUPPLEMENT
76 /// AUGUST 2013 WWW.PCTONLINE.COM
chances of this happening increase when
the bats leave or are excluded.
BIRD BUGS. Several species of cimicids
prefer to feed on birds, especially swallows,
swifts, pigeons and poultry. The swallow
bug, Oeciacus vicarius, is a common para-
site of cliff swallows, and to a lesser extent,
barn swallows. The bugs are most preva-
lent in western states where cliff swal-
lows are abundant. A century ago these
cimicids were mistaken for bed bugs and
a campaign was waged to eradicate swal-
lows throughout the country. Today these
acrobatic, benefi cial birds are protected by
federal and state laws. Swallow bugs can
be distinguished from bed bugs and bat
bugs by the presence of long, pale hairs on
the surface of the body (Fig. 4). They are also
somewhat smaller in size, and the front
margin of the pronotum is noticeably less
concave relative to bed bugs and bat bugs.
Swallow bugs proliferate in the gourd or
cup-shaped nests that the birds construct
from mud (often by the hundreds) on rock
facings, buildings and bridges. Infested
nests are usually laden with eggs and fecal
spots of the parasites.
Like other cimicids, swallow bugs must
adapt to their hosts. Cliff and barn swal-
lows migrate to the southern hemisphere
in late-summer/early autumn, returning to
their nests in northern locales the follow-
ing spring. Many of the bugs left behind
perish, but populations rebound when
the birds return, often reaching enor-
mous numbers by summer. When nests on
buildings are destroyed or abandoned, the
bugs may disperse indoors and bite people.
Swallow bugs are not known to transmit
diseases to humans. However certain vi-
ruses related to those causing western
equine encephalitis have been isolated
from bugs feeding on infected birds, rais-
ing questions about their vector potential.
The chimney swift bug, Cimexopsis nyc-
talis, is another cimicid sometimes found
in buildings, especially in eastern and
Midwest states. It’s a small elliptical spe-
cies (adults are about 1/8 inch), with a
smooth body and few obvious hairs (Fig.
5). Chimney swift bugs are often found in-
doors near fi replaces since their bird hosts
often nest within chimneys.
MANAGEMENT. Problems with bat bugs
and bird bugs typically arise when bats or
birds die, leave, relocate or are excluded
from their roosting or nesting sites. Lack-
ing their primary hosts, the bugs may at
times invade and bite people, especially
when infestations are large. Reactions
to the bites are similar to those from bed
bugs, and thus far, disease transmission
does not appear to be a factor.
As mentioned earlier, bat bugs and bird
bugs are usually noticed in the upper levels
of buildings near attics, roof lines, chim-
neys, etc. Within living areas, the bugs are
typically spotted here and there on ceil-
ings, walls and fl oors. Seldom, if ever, do
bat bugs or bird bugs congregate on beds,
couches and recliners in the manner of
Fig. 7. These big
brown bats were the
source of bat bugs in
a Kentucky home. No
pesticides were needed
in living areas which
was fortunate since the
owner was undergoing
chemotherapy.
Fig. 6. The odds of encountering bat bugs
increases with large roosting colonies. Dozens of
bat bugs were present in the guano on these steps.
BED BUG
SUPPLEMENT
WWW.PCTONLINE.COM AUGUST 2013 /// 77
bed bugs. Therefore it is normally not
necessary to treat these areas with in-
secticides (Fig. 7). Yet when pest con-
trol fi rms were polled about where
they treat for bat bugs or bird bugs,
more than half (56 percent), said
they treat “beds, couches and fur-
nishings within living areas,” alone (6
percent), or in conjunction with “at-
tics and other animal-roosting areas”
(50 percent). If non-bed bug cimicids
are determined to be the culprits,
roosting and nesting sites should be the
primary targets of treatment — con-
current with removal and exclusion
of bats or birds from the building.
Most respondents felt that bat
bugs and bird bugs were “easier” (41
percent) or “about the same” (52 per-
cent) diffi culty as bed bugs to elimi-
nate, whereas seven percent felt they
were “harder” to eliminate. In their
natural habitat, bat bugs and bird
bugs are seldom exposed to insecti-
cides therefore resistance is unlikely
to be a factor. Consequently products
such as pyrethroids should be effec-
tive. Treatment of roosting and nest-
ing areas may need to be thorough
since some of the bugs may have
dispersed. Additional targeted appli-
cations may be needed around attic
access doors, ceiling fi xtures, win-
dow frames, fi replaces, etc., where
wandering bugs may be hiding. Heat
treatment of attics, etc. can also be an
effective form of treatment.
A COLLABORATIVE EFFORT.
When
performing all animal remediation
work, it’s important to also consider
the potential for parasites and their
movement into buildings. Pest man-
agers and wildlife control specialists
may fi nd it useful to collaborate on
these services.
All photos copyrighted by the authors.
Michael F. Potter and Kenneth F. Haynes
are professors at the University of Kentucky.
Jennifer Gordon is a Ph.D. student at the
same institution. Erich Hardebeck is presi-
dent of Permakil Pest Control, Covington,
Ky., while Eric Arnold is owner of Bats, Birds,
& More, Inc. and Wildlife Control Training
Group, Sharon Center, Ohio. The authors can
be contacted at mpotter@giemedia.com.
The roof and wall panels of a Heat Assault 500X have been removed
to allow you to take a look inside. The large green container placed
standing in the middle of the trailer is a 400 liter reservoir full of
environmentally friendly Heat Transfer Fluid. Immediately in front of
the reservoir are TWO – 250,000 btu/hour coil burners that heat the
transfer fluid that will be pumped through custom designed hydraulic
hoses to the FIVE – unit heater/fan sets that would be positioned inside
the heat treatment area. Also notice that firmly attached to the tongue
is a 7.5 kW generator that has more than enough power for all of the
computer controls as well as providing spark for the coil heaters.
In an average 1500 square foot residential bungalow, the “kill zone”
temperature of 122F (50C) can be achieved within an hour of turning
on the circulation pump. Over the following few hours the heat
treatment area should continue to climb to a little over 140F (60C) to
be certain the walls are penetrated and the wall voids are at the “kill
zone” temperature to ensure a 100% success rate.
Within 6 to 8 hours your client is back in their bedbug free home and
you are going for dinner with a significant amount of money in your
pocket. Everyone wins.
www.heat-assault.com
1-877-474-2847
info@heat-assault.com
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