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David K. James, REHSAlameda County Environmental Health - Vector Control
October 20th, 2015
Biology of the Human Bed Bug Cimex lectularius
SINCE THE MID 1990’S, BED BUGS HAVE BECOME MORE COMMON
Bed bugs tend to be associated with poorly maintained and poor sanitary conditions, however …..
Any house is a good habitat for bed bugs. (A place to shelter and a food source is all they need)
A place to stay And something to eat
SERVICE REQUESTS ACVCSD• Initially infestations found in high-end hotels in
New York, Las Vegas, San Francisco (late 1990s to early 2000s)
• Now spread throughout the community nationwide.
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 20140
50
100
150
200
250
300
350
400
1 0 2 8 5 822 29
68
100
179 179
203
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343
Request For ServiceBed Bugs
Bed bugs
# o
f R
FS
BED BUG BIOLOGYSOME IMPORTANT ASPECTS FOR CONTROL
Order: Hemiptera ( Sub-Order: Heteroptera) Family: Cimicidae (74 spp) Genus: Cimex Species: lectularius
Piercing and sucking mouth parts
Feeds exclusively on the blood of mammals (related species on birds).
Preferred host of C. lectularius is HUMANS – (Much preferred)
Control implications: Pesticides are NOT ingested
Hemiptera: True bugs
Reduviidae: Triatoma spp.:Chagas disease
Leaf-footed bugHarlequin bug Cotton strainers
OTHER INSECTS & MITES WITH HUMAN HOSTS
Scabies mite
Tropical rat mites
Bird mite
Chigger
FAMILY CIMICIDAE
This family includes the parasites of animals.These ecto-parasites feed on the blood of birds and mammals, including bats.Bed bugs are flattened dorso-ventrally. Front wings are always reduced to small pads.All species live away from the host animal except when feeding.
Bedbugs are flattened dorso-ventrally. Front wings are always reduced to small pads.
RELATED SPECIES ATTACKING MAN
BAT BUG, Cimex pilosellus (Horvath) Occasional household pest
SWALLOW BUG, Oeciacus vicarius May enter homes when swallow nests removed
POULTRY BUG, Haematosiphon inodorus Found in hot dry areas Can become severe poultry pest May invade homes
CIM
EX
LE
CT
UL
AR
IUS
(LIN
NA
EU
S)
CO
MM
ON
H
UM
AN
B
ED
B
UG
Feeds prim
arily on hum
ans but will attack
bats, chickens and other m
amm
als
Worldw
ide distribution
Ancestor probably bat
parasite that utilized “cave dw
elling human”
Earliest record c.1350
BC
in Egypt
BED BUG LIFE CYCLE
Ectoparasites
Five nymphal stages and adults
Obligated blood feeders with all stages
Not implicated as a disease vector
1. Short life cycle – 30-45 days (under optimal conditions)[ 75-80% RH; 83-90o F ]
2. Eggs resistant to pesticides and heat and can be laid (glued) anywhere.
3. Females can lay 1-5 eggs per day. Hatch in 7-10 days
4. Blood meal needed to molt and for egg laying.
Only 10% of bedbugs will be feeding on a particular night
5. Most harbor near host (70%) but not all
6. Live in cracks and crevices, difficult to locate. Prefer rough surfaces
7. Bite is painless, most people don’t react initially. Older people react less to the bite.
Population can grow quite large before resident is aware of the infestation
8. Can go without Feeding for some time:1.
1st instars most vulnerable (14-36 days)5th and adults least vulnerable (42- 143 days)
9. Nymphs & adults stop feeding at 56oF (13oC) Thermal death point is 112oF @ 7 hrs, 118F (ad) 123F (eggs) @ 0 min
NO tarsal pads
No pads to pick up
pesticide
Tarsal padsHouse fly
Walk with body off the ground
Can walk over pesticide treated
area without being affected
Typical feeding position
• Feed between 12 & 6 AM
• Feed for 2-15 mins. Multiple feeding sites
Engorged bedbug
Harborage site, a short walking distance to restaurant
Blood/fecal spots on pillow case
All stages micturate
male
female
TRAUMATIC INSEMINATIONREPRODUCTION
Unusual reproduction – extragenital.Male punctures body wall of female to inject spermatozoa into the spermalege.Spermatozoa migrates to female genital tract.No courtship - mate rapidly.Mating occurs away from host.Females may travel some distance to get away from males.
Copulating couple
Male paramere
Beak or rostrum
Cleft of copulatory pouch (female)
Cimex lectularis tends to cluster in cracks, preferring old harborages and places which smell of bed bugs.
Meta-thoracic scent apparatus Host Detection: (when unfed)
Temperature Attraction to oily skin secretion and CO2 involved.
PESTICIDE RESISTANCE
Resistance to pyrethroids among bed bugs has become a major problem.
A number of resistant populations have been identified on the West Coast. An increasing number of resistant bed bugs are being found especially in the East Coast
• Pyrethroids bind to a protein in nerves called voltage-gated sodium channel prevent it from closing, causing continuous nerve stimulation.
• Resistant bed bug populations have evolved by changing the size of the pore (gate), preventing the binding of the pyrethroid.
• Resistance-associated genes have been found in the integument (cuticle) of the bed bug which could reduce insecticide penetration and enhance detoxification before reaching the target sites.
David K. [email protected]
To Conclude
The more you know about Bed bugs…
The easier it is to control (kill) them.