Insects living in hiding are easy to adapt to the dark

A lifelong beetle crawling in grains cannot recognize all colors, and its eyesight doesn't follow normal rules. Most other insects can see 3 colors: they are very sensitive to ultraviolet, green and light wavelengths. Scientists have now discovered that the bug has no light-stimulating receptor, which is sensitive to long-wavelength green light.

The species of red-flour weevil (Tribolium castaneum) is a very common harmful insect that specializes in cereal products, living in hiding

The species of red flour weevil (Tribolium castaneum) is a very common harmful insect that only has an 1/8 inch long, it eats the shelled grains. This species of the beetle lives in the dark and has lost its light-stimulating receptor, which is sensitive to long-wavelength green light. (Photo: Peggy Gred, USDA Agricultural Research Service, Bugwood.org)

I am in the dark. Markus Friedrich of Wayne State University in Detroit and colleagues from St Louis and Cincinnati conducted genetic analysis to understand the evolution of the insect's vision.

Opsin gene group plays a key role in vision. The authors found that the retina's double-eyed retina lacks the Opsin gene - green that encodes the light-stimulating receptor. The species of red powder weevil is also considered the first example of an insect that has two Opsin genes that affect the entire retina. The combined effects of these two genes have broken the 'one receptor rule' of sensory cells.

Research shows that the beetle has gained advantage through its adaptation process. Dr. Friedrich said: 'Increasing the ability of the combination of Opsin genes is very beneficial in conditions when sensitivity to light becomes unnecessary.'

The study opens a way for further research into the development and biological mechanisms of harmful insects. The species of red powder weevil can be a prospective research object for the deeper study of the evolution of hidden animals.