Image of the Day: Legless Leaps

The goldenrod gall midge, a type of fly, bears larvae that can jump through the air despite their lack of limbs.

Aug 12, 2019
Nicoletta Lanese
A time-lapse image of a gall midge grub (Asphondylia) leaping through the air. Scale bar five mm 
REPRODUCED/ADAPTED WITH PERMISSION OF JOURNAL OF EXPERIMENTAL BIOLOGY, FARLEY, G.M., WISE, M.J., HARRISON, J.S., SUTTON, G.P., KUO, C. AND PATEK, S.N., 2019, VOLUME 222, DOI:10.1242/jeb.201129  

The legless young of the goldenrod gall midge (Asphondylia) can launch themselves skyward and land up to 20–30 body-lengths away, researchers reported August 8 in the Journal of Experimental Biology. A three-mm-long gall midge larva grows several sticky patches of skin, lined with finger-like scales. By sticking these patches together, a larva can latch its head to its tail, form a ring, and shift its internal fluids towards its tail end. When the pressure proves too great, the latch releases and the grub springs from the ground.

The researchers found that, during this process, a “transient leg” appears about a third of the way up the larva’s tail and provides thrust for take-off, they explain in an announcement. The team now plans to figure out exactly what makes gall midge larvae so sticky.

A scanning electron microscope image reveals one-micron projections on the adhesive patches of a leaping gall midge larva.
GRACE FARLEY, DUKE UNIVERSITY

G.M. Farley et al., “Adhesive latching and legless leaping in small, worm-like insect larvae,” doi:10.1242/jeb.201129, J Exp Biol, 2019.

Nicoletta Lanese is an intern at The Scientist. Email her at nlanese@the-scientist.com.