Color is important to insects

TRAPPING THE SAWFLY  —  A team working on the development ofa trapping system for wheat stem sawfly is from the left, Jeffrey Olson, Vickie Ophus, Research Assistant-III, Rachel Bokma, Morgan Fowler, Nathan Gage, Dr. Kim Tangtrakulwanich, Post-Doctoral Fellow, and Dr. Gadi V.P. Reddy, Superintendent and Entomologist, WTARC.  Photo courtesy of the Ag Research Station





Why color is critical for nocturnal insects is an ongoing debate.

Nocturnal-insect taxa discriminate flowers at starlight intensities whereas humans and honeybees cannot. Nocturnal insects use chromatic cues rather than achromatic cues to recognize flowers.

The fast-flying nocturnal sweat bee relies on vision as a principal sense and is capable of foraging and homing by using visually discriminate landmarks at starlight intensities.

Use of visual cues is well documented in predatory insects: for example, the larvae of tiger beetles visually discriminate prey organisms within their hunting range of 10-15 mm.

Also, many examples illustrating use of visual cues in mate location exist. Similarly, the many insects use chemicals for mating, mostly females release pheromone that attract males while there are some males (for example: pine beetle) release aggregation pheromone that attracts both sexes.

A team of researchers from Montana State University Western Triangle Ag Research Center is currently working on developing pheromone trapping system for the wheat stem sawfly.

Wheat stem sawfly is currently one of the main problems Montana wheat growers are facing. Although pheromone compounds have been identified and used in the field, the baited trap attracts sawfly poorly in the field.

The entomology and ecology team of WTARC is trying to look into other factors that can influence the adult trap catches.

For example, says Dr. Gadi V.P. Reddy, the Superintendent/Entomologist at the WTRAC, “Eight different colored traps (yellow, brown, red, grey, blue, black, white, and green) have been installed to see what colored trap catches the highest number of wheat stem sawfly adults.”

He goes on to add, “Once we know the specific color cues work synchronously with the olfactory cues (pheromones) and such a coordinated function can be useful in exploring insect trapping for either controlling or monitoring their abundance in the fields.”

This work is funded by the Montana Wheat and Barley Committee.