Moths and Other Four-Winged Insects Use Gyroscopic Antennae for Flight Control

The hawk moth Manduca sexta.

[Images courtesy of Armin Hinterwirth; University of Washington, Dept of Biology, Daniel Lab]

The moth, a four-winged insect, has sophisticated sensory capabilities on its antennae that serve as a gyroscope to help it navigate while flying, according to new research in the 9 February issue of Science.

Although researchers have documented two-winged insects like the housefly and mosquito using their vestigial hindwing, a pendulum-shaped appendage called a "haltere," to provide stability in flight. But they had not described how four-winged insects like the moth maintain flight stability, especially when hovering to collect nectar from flowers.

Sanjay Sane, a biologist at the University of Washington, Seattle, and colleagues found that the antennae of the Manduca sexta (hawk moth) serve a function like that of the halteres, sensing small vibrations and changes in body position via hairs at their base.

In one of their experiments, the researchers removed parts of the moth's antenna and found that "the moths can take flight, but not stably hover or execute controlled maneuvers." By gluing the antenna back on, the researchers discovered, the moth regained its flight stability.

Scientists hypothesize that the gyroscopic antennae were an adaptation to the moth's navigation in low-light conditions.

The authors note that while insects flying in well-lit conditions can rely on visual cues for flight control, "insects flying under low-light (moths) . . . may not be able to rely entirely on their visual systems to assess self-motion to generate rapid maneuvers."

Benjamin Somers and Kathy Wren

8 February 2007