Читать книгу Extreme Insects - Richard Jones - Страница 18

NAME	twenty-plumed moths in the genus Alucita
LOCATION	worldwide
ATTRIBUTE	more wings than any other insects

Adult insects usually have two pairs of wings. Some groups have fewer: flies have only one pair; lice and fleas have none at all. Even beetles, which might look as if they have none at first, still have four wings; two are developed into the hard shell wing-cases, and cover the delicately folded flight wings underneath. But could this be a moth with twenty wings?

Plume moths have long, narrow, hairy wings that resemble birds’ feathers. At rest they fold their wings up tightly to resemble twigs and dead grass stems. In some species the wings are split into hairy fingers, each finger acting as a structural vein to expand the narrow wings into a broader aerofoil in flight. The greatest splitting occurs in the twenty-plume moths, where each of the four ‘true’ wings is divided right down to the base into a fan of finger-wings. Whoever named the moth miscounted. In fact, it has 24 plumes.

The plumes of these moths are analogous to the veins that spread through all insect wings. The veins are most obvious in clear-winged insects such as bees, wasps and flies. Insect wings are thought to have evolved from broad flap-like appendages used as gills by their aquatic predecessors, and the veins are the vestiges of breathing tubes. Such gill flaps are still visible today in the larvae of stoneflies (Plecoptera) and mayflies (Ephemeroptera).

Insects are thought to have evolved wings only once, about 400 million years ago. After examining the different wing structures, scientists now believe that the first truly flapping and flying insects had eight veins in each wing. Over evolutionary time these have often become merged with each other or reduced to six main veins. These six archetypal veins are clearly seen in Alucita.