Nonchemical Cues

While research has focused primarily on chemical cues (and justly so), mate finding and courtship may be mul-

Fig. 6.1 Calling behavior in female Parcoblatta lata. Females in the calling posture raise the body up from the substrate and alternate between two positions: (A) upward with longitudinal compression, and (B) downward with longitudinal extension. From Gemeno et al. (2003), courtesy of César Gemeno, with permission of Journal of Chemical Ecology.

Fig. 6.1 Calling behavior in female Parcoblatta lata. Females in the calling posture raise the body up from the substrate and alternate between two positions: (A) upward with longitudinal compression, and (B) downward with longitudinal extension. From Gemeno et al. (2003), courtesy of César Gemeno, with permission of Journal of Chemical Ecology.

Fig. 6.2 Male Lucihormetica fenestrata Zompro & Fritzsche, 1999 (holotype) exhibiting its pronotal "headlights." Copyright O. Zompro, courtesy of O. Zompro.

timodal in a number of species, that is, they integrate chemical, visual, tactile, and acoustic signals. Vision apparently plays little or no significant role in sexual recognition, courtship, or copulation in the species typically studied in laboratory culture (Roth and Willis, 1952a). However, in many cockroaches the males have large, well-developed, pigmented eyes,suggesting the possibility that optical cues may be integrated with pheromonal stimuli during mate seeking and mating behavior. Visual orientation seems particularly likely in Australian Polyzosteri-inae and in brightly colored, diurnally active blattellids. The delightful discovery of pronotal headlights on males of Lucihormetica fenestrata suggests that even nocturnally active cockroaches may use sight in attracting or courting mates (Zompro and Fritzsche, 1999). This species lives in bromeliads in the Brazilian rainforest and has two elevated, kidney-shaped, strongly luminescent organs on the pronotum (Fig. 6.2). These protuberances are highly porous (probably to allow gas exchange) and absent in nymphs and females. Males of several related species sport similar structures, but because live material had never been examined, their function as lamps was unknown.

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