Behavioral Responses of Nymph and AdultCimex lectularius(Hemiptera: Cimicidae) to Colored Harborages

Abstract

Behavioral bioassays were conducted to determine whether bed bug adults and nymphs prefer specific colored harborages. Two-choice and seven-choice behavioral color assays indicate that red (28.5%) and black (23.4%) harborages are optimal harborage choices for bed bugs. Yellow and green harborages appear to repel bed bugs. Harborage color preferences change according to gender, nutritional status, aggregation, and life stage. Female bed bugs prefer harborages with shorter wavelengths (lilac-14.5% and violet-11.5%) compared to males, whereas males prefer harborages with longer wavelengths (red-37.5% and black-32%) compared with females. The preference for orange and violet harborages is stronger when bed bugs are fed as opposed to when they are starved. Lone bed bugs (30%) prefer to be in black harborages while red harborages appear to be the optimum harborage color for bed bugs in more natural mixed aggregations (35.5%). Bed bug nymphs preferred different colored harborages at each stage of development, which is indicative of their developing eye structures and pigments. First instars showed no significant preference for any colored harborage soon after hatching. However, by the fifth instar, 27.5% of nymphs significantly preferred red and black harborages (which was a similar preference to adult bed bugs). The proportion of oviposited eggs was significantly greater under blue, red, and black harborages compared to other colored harborages tested. The use of visual cues such as specific colors offers great potential for improving bed bug monitoring tools by increasing trap captures.

Vision in the common bed bug Cimex lectulariusL. (Hemiptera: Cimicidae): eye morphology and spectral sensitivity

“…McNeill et al . () reported similar intensity in reflectance from green and red papers (∼40%) and a stronger preference for red harborages, possibly indicating detection of red over green based on wavelength, and this merits additional study. Previous studies have concluded that while red visual photopigments may be absent, red light may be detected through the presence of screening pigments that broaden the long wavelength portion of the green pigment absorption curve (Döring & Chittka, ).…”

“…Behaviourally, green harborages were the most avoided by adult bed bugs (Singh et al ., ; McNeill et al ., ). In contrast, red harbourages (λ max 639 nm) were the most preferred (McNeill et al ., ).…”

“…Blue targets against green backgrounds are well known to be attractive to blood‐feeding flies such as tsetse flies and horse flies (Challier et al ., ; Allan & Stoffolano, ; Allan et al ., ) for which spectral sensitivity studies support the presence of blue photopigments (Green & Cosens, 1983; Allan et al ., ). Behaviourally, blue harbourages have been selected by C. lectularius (Singh et al ., ; McNeill et al ., ). However, the role of light intensity was not excluded in either study.…”

“…While one photopigment ( max 520 nm) is clearly present, the broadened curve may represent the presence of additional pigments, either screening pigments or an additional photopigment, which enhance light absorption at higher wavelengths. In studies that have focused on preference to coloured papers for harborage without balancing light intensity, bed bug responses generally appeared to reflect a stronger preference for darker areas (Aboul-Nasr & Erakey, 1969;Singh et al, 2015;McNeill et al, 2016). McNeill et al (2016) reported similar intensity in reflectance from green and red papers (∼40%) and a stronger preference for red harborages, possibly indicating detection of red over green based on wavelength, and this merits additional study.…”

“…For example, in blood-feeding tabanid flies, visual sensitivity to yellow-green was important to provide a contrast of potential hosts against the yellow-green salt marsh habitat (Allan et al, 1991). Behaviourally, green harborages were the most avoided by adult bed bugs (Singh et al, 2015;McNeill et al, 2016). In contrast, red harbourages ( max 639 nm) were the most preferred (McNeill et al, 2016).…”