Skull Moths: Moths are clever long-distance fliers

skull moth
Moths are clever long-distance flyers

A skull hawk moth with a transmitter.  Photo: Christian Ziegler/Max Planck Institute of Animal Behavior/dpa

A skull hawk moth with a transmitter. photo

© Christian Ziegler/Max Planck Institute of Animal Behavior/dpa

For the first time, researchers are tracking insects more than 80 kilometers in an airplane. They discovered that the animals can navigate much more skilfully than was previously known.

Some insects are similarly skilled long-distance flyers as birds, according to researchers. An international team equipped moths with transmitters and tracked them over a distance of up to 80 kilometers with a light aircraft.

This is the longest distance an insect has ever been observed in the wild, said ecologist Martin Wikelski, who Max Planck Institute for behavioral biologist and researches at the University of Konstanz. Previous detailed studies on the movement of insects have been carried out over a maximum of one to two kilometers.

Up to 4000 kilometers

Overall, the studied squirrel hawk moths (Acherontia atropos) pause on their migrations Europe and Africa, according to the researchers, each back up to 4000 kilometers. The study was published in the journal "Science" and proves that the moths use sophisticated flight strategies to adapt to the prevailing wind conditions and thus precisely maintain their flight direction over long distances.

Insects are usually too numerous to tag and retrieve and too small to carry tracking devices, explained first author Myles Menz, who worked at the Max Planck Institute during the study. For their study, however, the researchers equipped the squirrel hawkmoth, which is extremely large for an insect and weighs 3.5 grams, with a radio transmitter that weighs just 0.2 grams. With an airplane and an antenna attached to it, they tracked the moths of constancy out to the Alps.

The data recorded show that the moths did not wait until the wind was favorable for them. Instead, they employed a variety of flight strategies to adapt to prevailing wind conditions and stay on course throughout the night. So when the wind was favourable, they flew high so that they let it support them. In strong headwinds or crosswinds, on the other hand, they flew low and increased their speed to stay on course.

True navigation experts

For years it was assumed that insects were mainly driven by the wind during long-distance migration, said Menz. 'However, we were able to show that insects can be true navigation experts, on par with birds, for example, and that they are far less vulnerable to adverse wind conditions than we thought.'

In further investigations, the researchers now want to pursue the question of how the moths manage to fly in a straight line. Based on previous lab work, there's some likelihood that the insects use internal compasses, both visual and magnetic, to chart their global flight paths, Menz explained.


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