The dragonfly, it turns out, is
one of the most accurate prey capturers in nature, and one of the best fliers
too.
In an instant, it darts from a
perch atop a cattail to intercept a tiny insect – the mosquito – for a quick
meal.
So you can imagine how difficult
it is for researchers like Prof. Rob Olberg and his students Rebecca Seaman '04
and Jon Jackson '04 to capture the predators on film.
This summer, in the southwest
corner of the Science and Engineering Courtyard, they set up a “Dragonfly
Flight Cage,” a contraption that looks a lot like one of those screen
gazebos favored by the lakeside party set. But inside is a miniature ecosystem
complete with a pond (read: kiddie pool) and an assortment of vegetation that
comes natural to Odonoatarium.
The researchers tempt the fliers
with tiny glass beads that resemble a mosquito, and record the action on
high-speed video. Back in the lab, they analyze the footage, paying special
attention to head motion before and after it catches its food. Their goal:
learn as much as possible about how the dragonfly can so effectively catch food
in mid-air.
The project is supported by a
grant from the National Science Foundation.
Olberg notes that the experiment
went well, except that they had to change test subjects every few days. Besides
being great predators, the dragonfly, it turns out, can learn a thing or two
about glass beads and researchers.