Bed Bug Management - Urban Insect Pests: Sustainable Management Strategies - page 11

armchairs, and seats of buses, trains and
aeroplanes.
In addition to regular access to a host,
bed bugs require a harbourage in which to
hide between feeds. A typical harbourage
consists of a narrow crevice between two
hard surfaces in close proximity to the
feeding site. This is where the bed bugs
spend the majority of their time and
consequently these crevices quickly become
littered with cast skins, eggs and faecal
material (see Fig. 2.2d).
Bed bugs prefer to reside together in
aggregations of tens or even hundreds of
individuals, spanning all age classes and
both sexes. It is believed that this behaviour
helps conserve water (Benoit et al ., 2007).
They emit aggregation pheromones, which
aid in locating each other and also enable
them to relocate harbourages after feeding
(Siljander et al. , 2008).
Hungry bed bugs can initiate foraging
behaviour spontaneously, although it is
more commonly triggered by elevated
carbon dioxide from the host (Reinhardt
and Siva-Jothy, 2007). Foraging bed bugs
locate the host by a combination of host
cues. Carbon dioxide is probably the
longest ranging cue that the bed bugs can
detect but their ability to follow up a carbon
dioxide concentration gradient is unknown.
Host body heat is an important directional
cue for bed bugs within 1.5 m of the host
(Reinhardt and Siva-Jothy, 2007). Sweat
and sebaceous gland secretions are
important for close range host location just
prior to contact (Aboul-Nasr and Erakey,
1968).
Bed bugs can disperse actively, by
walking to a neighbouring room or apart-
ment, or passively, when they are carried
accidentally on luggage or furniture. Active
dispersal is probably limited to a few tens of
metres, but passive dispersal has the
potential to transport them anywhere in the
world.

does not react to the bites. Infestations in
buildings with a high turnover of potential
hosts, such as hotels, hostels or hospitals,
can also be hard to detect because skin
reactions to bites often only become evident
after the host has moved on (Doggett et al.,
2012). If left unchecked, infestations can
rapidly grow and spread, so early detection
is crucial in mitigating both the costs and
the extent of the disturbance.

Monitors

Many bed bug monitoring devices have
appeared on the market in recent years that
seek to provide the solution to early detec-
tion. Some bed bug monitors exploit the
bed bug's harbourage-seeking behaviour,
often utilizing synthetic aggregation phero-
mones. Others exploit the host-seeking
behaviour, utilizing carbon dioxide and/or
heat and/or synthetic mimics of host
kairomones. Costs vary considerably, but
with little impartial data on the effi cacy of
any of these devices it can be diffi cult to
choose between them.
Despite the abundance of monitoring
devices currently available, there has not
been wide take-up of the technology in the
hospitality industry so far. Some feel that
the low probability of encountering a bed
bug infestation does not justify the cost of a
proactive measure such as installing a
monitoring system. Furthermore, the time
taken to check monitors can be prohibitive.
Room processing times for hotel cleaning
staff are frequently limited to a few minutes
and checking monitoring devices for bed
bugs can signifi cantly extend the processing
time leading to higher staff overheads.
Proactive monitoring devices may become
more widely adopted if litigation by dis-
gruntled guests against infested hotels
becomes more commonplace and moni-
toring devices become an accepted demon-
stration of due diligence by the hotels.

Bed Bug Detection

Visual inspection

The cryptic nature of bed bugs frequently
allows infestations to go undetected for
prolonged periods, particularly if the host

Regular visual inspections can play an
important role in the early detection of bed