Sweetpotato Weevil's Color Preference Changes from Outdoors to Indoors

One of the most destructive insects, the sweetpotato weevil, is attracted to certain colors. This feature may help in fighting against these pests, claims a new finding.

The destructive shiny, black ant-like insect, sweetpotato weevil (cylas formicarius), is known to hamper the production of sweet potatoes. It is a major threat in fields as well as in storages. Chemical control is ineffective in curbing them. But after years of investigation, researchers at Montana State University have discovered an innovative technique to control the spread of these damaging insects without the use of toxic pesticides.

Mass trappings with synthetic pheromones are used to suppress the insect's population. But this technique is not totally effective on the sweetpotato weevil males. But this new study claims that color may be a useful weapon in fighting these insects.

Prior to this, Dr. Gadi V.P. Reddy of Montana State University in collaboration with Nirupa Gadi of University of Guam had discovered that the sweetpotato weevils were more attracted to color red. Knowing their preference for color the researchers set out to find if this held true even in indoor conditions.

To proceed with the finding, the team set a trap of eight different colors and they noticed that the insects were more attracted to green traps especially in indoor conditions and in the fields they were attracted to red traps.

"Sweetpotato weevils responded to pheromone baited traps of different colors differently in the field and indoors," said Dr. Reddy. "In the field, sweetpotato weevils preferred red, and particularly light red, over the other colors, but indoors, green traps were favored. We have no explanation for the difference. Further studies focusing on why insect behavior changes from outdoors to indoors will be required to find out."

"If we use proper color...we can see a 40% increase in catching the weevil," Reddy told Nature World News in an email.

The study was published in Annals of the Entomological Society of America.