A red light puts moths in the mood

Will you dim the light and turn on the red light for a romantic night out with your partner? Moths don’t seem to be that different. New study published in Boundaries in Genetics shows that dim red light stimulates sexual activity in a model sex, the yellow peach moth Conogethes punctiferalis (family Crambidae), by selectively activating a genetic pathway associated with olfaction in the antennae. This pathway eventually makes males more sensitive to the smell of the female sex pheromone and therefore more motivating to mate.

“We usually use red lights when working with our moths because long white light can stop them from coming together,” says lead author Dr Wei Xiao, a scientist from Southwestern University in Chongqing, China. ”However, we realized that the moths were laying more eggs when we shone a red light at the dark stage of their daily dark-dark circle, and we wanted find out what molecular mechanisms underlie this change. “

Odorant-binding proteins (OBPs) are small proteins secreted by supporting cells around olfactory receptor neurons in insect antennae. Xiao and colleagues first used quantitative PCR (qRT-PCR) to show that two OBPs, encoded by the genes CpunOB2 and CpunPBP5, are more abundant in male antennae C. punctiferalis exposed to ambient light (around 2 lux) than in antennae exposed to darkness or light by other wavelengths. The authors maintain that the relatively long wavelength of red light enables it to penetrate into cells and cells and then stimulates the sensation of CpunOB2 and CpunPBP5 with a device that does not it has yet to be confirmed.

Xioa et al. they then used another molecular method, a fluorescence binding assay, to show that these OBPs, when expressed reproducibly in E. coli bacteria, bind selectively to known molecules as parts of the female sex moth pheromone. With electroantennography, a technique that measures electrical activity in antennae in response to stimuli, they went on to show that male antennae become more responsive to female sex pheromone after exposure to red light. Finally, they used behavioral tests to determine the ultimate effect of red light on both males and females C. punctiferalis encouraging courtship and egg laying.

Xiao et al. concluded that, for this species at least, dim red light is sufficient to cause olfactory receptor neurons in male antennae to become hypersensitive to components of the female sex pheromone, ultimately ‘promotes reproductive behavior in adult moths.

Although the yellow peach lion itself is not endangered, Xiao ‘s study may help stimulate breeding in endangered species, or economically important species.

“Our study is the first to test the stimulating effects of red light on coupon behavior and as such is a potential starting point for research on novel conservation methods for insecticides. is in danger, “Xiao said.

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