Researchers Learn How Insects Come Out from Under the Rain

Microfibres on the march fly's wings shed water quickly and efficiently

For insects, water droplets are major hazards, weighing them down and throwing them off balance. Fortunately, the micro-fibres, called microtrichia, that cover insect wings help to shed water droplets that might otherwise endanger insects while in flight.

Researchers at the University of Alberta and the University of Calgary noticed that microtrichia face different directions at different locations of the wing of the march fly (Penthetria heteroptera). From observations under the microscope, they then developed a model that successfully predicts the orientation of these micro-fibres at different locations on the wing.

“For an insect there are three tricks to shedding water from the wings,” says Morris Flynn, Associate Professor of Mechanical Engineering at the University of Alberta. “First, water must not get stuck in the grooves on an insect’s wing. Second, water needs to be shed from the wings as readily as possible. But third, the water can’t go just anywhere. It needs to be shed away from the body.”

Flynn and his collaborators, Delyle Polet (University of Calgary, Dept. of Biological Sciences) and Dr. Felix A. H. Sperling (University of Alberta, Dept. of Biological Sciences) determined that the orientation of the microtrichia is an optimization of these three factors. 

“Delyle Polet developed weighting factors to account for these different considerations,” says Flynn. “The weighting factors can be adjusted when studying different species of insect that have a different body mass or wing dimension.” On this basis, the researchers expect that their model may serve as a helpful tool in understanding wing microtrichia orientation in other insects as well. 

Read the article here.