This study examined the effects of different life stages (first, second, third, fourth, and five instars; adult females and adult males) and feeding regimes (starved and blood fed) on the active movement activity of the tropical bed bug, Cimex hemipterus (F.), under mixed-stage conditions. We used an extended arena made from Tygon tube coils and observed the movement frequency and movement distance at selected time intervals up to 120 h. The fifth instars and adult males and females showed significantly (P < 0.01) greater movement frequency compared with the other stages. The first and second instars showed limited movement (< 8 m) over the experimental period. Starved bed bugs showed greater movement frequency compared with blood-fed bed bugs, with the exception of adult females. Blood-fed adult females exhibited significantly (P < 0.01) greater movement frequency and distance compared with starved females. Blood-fed females moved up to 42.3 m over 120 h. Regression analysis between movement distance of the fifth instars and adults and the time intervals revealed a positive relationship (r2 = 0.6583; P < 0.01), suggesting that delays in bed bug control efforts will increase the risk of the greater infestation. During bed bug inspection, the presence of only late instars and adults in premises would indicate a new infestation, whereas an established infestation likely would consist of mixed stages.
The climbing abilities of two bed bug species, Cimex lectularius L. and Cimex hemipterus (F.), were determined by evaluating their escape rates from smooth surface pitfall traps using four commercial bed bug monitors (Verifi Bed Bug Detector, ClimbUp Insect Interceptor, BlackOut Bed Bug Detector, and SenSci Volcano Bed Bug Detector). All detectors were used in the absence of lures or attractants. Unlike C. lectularius, adult C. hemipterus were able to escape from all traps. On the other hand, no or a low number nymphs of both species escaped, depending on the evaluated traps. Examination of the vertical friction force of adults of both species revealed a higher vertical friction force in C. hemipterus than in C. lectularius. Scanning electron microscope micrograph observation on the tibial pad of adult bed bugs of C. hemipterus showed the presence of a greater number of tenent hairs on the tibial pad than on that of adult C. lectularius. No tibial pad was found on the fourth and fifth instars of both species. Near the base of the hollow tenent hairs is a glandular epithelium that is better developed in adult C. hemipterus than in adult C. lectularius. This study highlights significant morphological differences between C. lectularius and C. hemipterus, which may have implications in the monitoring and management of bed bug infestations.
This study examined the fecundity, oviposition, nymphal development and longevity of field-collected samples of the tropical bedbug, Cimex hemipterus (Fabricius) (Hemiptera: Cimicidae). Under environmental conditions of 26+/-2 degrees C, 70 +/- 5% relative humidity and a 12-h photoperiod, with bloodmeals provided by a human host, six strains of tropical bedbug had a fecundity of up to 50 eggs per lifetime, over 11-14 oviposition cycles. Increased feeding frequency improved fecundity. After feeding and mating, adult females normally took 2-3 days to produce a first batch of eggs. The oviposition period lasted 2-7 days before cessation of the oviposition cycle. The egg incubation period usually lasted 5-7 days before the emergence of first instars. The nymphs underwent five stadia (the first four of which each took 3-4 days, whereas the last took 4-5 days) before becoming adults at a sex ratio of 1 : 1. More than five bloodmeals were required by the nymphs to ensure a successful moult. Unmated adults lived significantly longer than mated adults (P < 0.05). Unmated females lived up to almost 7 months, but the longevity of mated males and females did not differ significantly (P > 0.05).
Five formulated insecticides (lambda-cyhalothrin at 10 mg m⁻², bifenthrin at 50 mg m⁻², fipronil at 10 mg m⁻², fenitrothion at 50 mg m⁻², imidacloprid at 5 mg m⁻²) and one active ingredient (DDT at 500 mg m⁻²) were evaluated using a surface contact method against early and late instars and adults of two strains of the tropical bed bug, Cimex hemipterus (F.). Synergism of lambda-cyhalothrin and fipronil using piperonyl butoxide (PBO) was also assessed.