Biological parameters, environmental effects, dispersal behaviour and toxicological studies of the tropical bed bug, cimex hemipterus (fabricius) (hemiptera: cimicidae)
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Date
2010
Authors
Yee Fatt, How
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Abstract
This thesis describes the biology, environmental effects, and dispersal behavior
of the tropical bed bug, Cimex hemipterus (Fabricius), as well as the toxicological
effects of eight insecticides (lambda-cyhalothrin, bifenthrin, fenitrothion, fipronil,
imidacloprid, indoxacarb, chlorantraniliprole and DDT) on this species. The resurgence
of bed bug infestations in recent years and infestation management also are discussed.
A total of 54 bed bug infested sites (e.g., hotels, public accommodations, and
residential premises) in Malaysia and Singapore were surveyed between July 2005 and
December 2008. C. hemipterus was the only species found. Bed bug infestations were
more common in hotels and public accommodations compared to residential premises.
Bedding (31.09%), the headboard (30.25%), and cracks and crevices surrounding the
baseboard, wall, or floor (23.53%) were the three most common locations of infestation.
Fecundity, oviposition, egg incubation, nymphal development, and longevity of
C. hemipterus were the biological parameters studied. Under laboratory conditions,
fecundity could reach 50 eggs per lifetime over 11-14 oviposition cycles. After feeding
and mating, adult females normally took 2-3 days to produce the first batch of eggs.
The oviposition period lasted between 2-7 days before cessation of the oviposition
cycle. The egg incubation period usually ranged from 5--7 days before hatching. The
nymphs underwent five stadia before becoming adults with a sex ratio of 1: 1. Unmated
adults lived significantly longer than mated ones (P<0.05).
Temperature and relative humidity (RH) both affected bed bug survival. Cimex
hemipterus survived longest under low temperature (20°C) and high RH (75-100%).
Survival and water loss were significantly affected (P<O.OI) by temperature and RH
(either singly or in interaction). Strain and sex also significantly (P<O.O I) influenced
bed bug survival. Water loss profiles further explained the initial death of bed bugs after
losing 35-45% of their water content.
The 5th instar, adult males, and adult females were the three most active
dispersal stages. Starved insects showed greater dispersal frequency compared to blood~
fed individuals, with the exception of adult females. The blood-fed females can move
up to >40 m after 120 hours.
Of the eight insecticides tested against early, late, and adult stages of bed bugs,
lambda-cyhalothrin, bifenthrin, fenitrothion, and fipronil were efficient in bed bug
control. The late stage individuals exhibited the highest significant L Tso among the life
stages tested. Different strains or life stages exhibited varied tolerance to the tested
insecticides. The effectiveness of lambda-cyhalothrin and fipronil can be synergized
with piperonyl butoxide (PBO).