Like Humans, Moths Prefer Dim Red Light for a Romantic Night

Humans usually dim the light and have the warm light turned on for a more romantic night with their partner--- and moths happen to do the same in that regard.

This research Frontier in Genetics published showed that dim red light enhances sexual activities in moth species used as models, the yellow peach ones also called Conogethes punctiferalis, as seen on Shrikant Kelkar's YouTube video below, or family Crambidae, by selectively stimulating a genomic trail associated with olfaction in the antennae.

Such a pathway is eventually making males more sensitive to the smell of the female sex pheromone and, therefore, more encouraged to mate.

According to Dr. Wei Xiao, a Chongqing, China-based scientist, they typically use red lights when they work with their moths as extended white light can preempt them from mating.

Xiao, who's also the study's lead author, added, nonetheless, they realized that the moths were laying more eggs when his team shone red light during their daily light-dark cycle's dark phase. They wanted to identify the molecular mechanisms underlying such a change.

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'Odorant Binding Proteins'

Essentially, odorant-binding proteins or OBPs are tiny proteins concealed by auxiliary cells surrounding olfactory receptor neurons in the insects' antennae.

Xiao, together with colleagues, originally used qRT-PCR or qualitative PCR to present that two OBPs that genes CpunOB2 and CpunPBP5 encoded are found to be more plentiful in antennae exposed to either light or darkness with other wavelengths.

According to a Phys.org article, the study investigators speculate that the red light's comparatively long wavelength allows it to penetrate the tissues and cells, and there kindles the expression of the genes mentioned by a yet-to-be-identified mechanism.

Another Molecular Technique

Xiao's team then applied another molecular technique identified with fluorescence binding assay. The said OPBs, when recombinantly conveyed in E.coli bacteria, selectively attach to molecules, are known to be elements of the female sex pheromone of the moth.

In addition, with electroantennography, a method that gauges the electrical antennae as a response to stimuli, they continued to exhibit that the male moths' antennae turn out to be more reactive to female sex pheromone following exposure to red light.

And lastly, the research team utilized behavioral investigations to confirm that the ultimate impact of red light on male and female Conogethes punctiferalis is to encourage mating and laying of eggs.

Show and colleagues have now concluded that for this species, at least, dim red light is adequate to cause olfactory receptor neurons in the antennae of males to turn out to be oversensitive or excessively sensitive to components of the female sex pheromone, eventually encouraging reproductive behaviors among adult moths.

Even though yellow peach moths themselves are not endangered, this study of Xiao and the team could boost reproduction in endangered species or species that are essential economically.

The study's lead author said their study is a pioneer in testing the stimulatory impacts of red light on mating behavior and is thus, a probable springboard for research into innovative conservation strategies for endangered insects.