Despite their variety today, all winged insects share a similar body plan, honed over 300 million years of evolution. Each has a thorax in three segments, with a pair of legs on each segment, and a pair of wings on the second and third segment.
and colleagues at the National Centre of Scientific Research in Marseille, France, have just found an exception. Despite their spectacular appearance, the “helmets” of attach to the first segment of the thorax, in the same way as wings. The team say they are essentially an extra pair of highly modified wing-like appendages.
Journal reference:
Cladonota
Treehoppers () are related to the cicadas. There are over 3000 species, and treehoppers live on every continent except Antarctica. Their most prominent feature is the helmet, which comes in a variety of odd shapes. This treehopper, Cladonota, has a bizarre horseshoe-shaped helmet.
(Image: Nicolas Gompel/Nature)
Oeda
This genus, Oeda, has a delicate amber-coloured helmet.
(Image: Nicolas Gompel/Nature)
Membracis
When Prud’homme and colleagues took a closer look, they saw that that the helmet attaches to the first segment of the thorax at two points, on either side of the body. That is reminiscent of the way wings attach to the second and third segment of the thorax. This piebald version belongs to the genus Membracis.
(Image: Nicolas Gompel/Nature)
Stegaspis
The wings of this genus of treehopper, Stegaspis, are clearly visible – but they are rivalled by its large orange helmet.
(Image: Nicolas Gompel/Nature)
Cyphonia
Losing wing-like structures through gene suppression may be relatively common, but gaining them again is very unusual. In fact, Prud’homme and colleagues say the treehoppers’ helmet is an “unprecedented” innovation in millions of years of insect body plan evolution. Cyphonia‘s helmet mimics an aggressive ant species.
(Image: Nicolas Gompel/Nature)
Anchistrotus
The helmet’s true origins may have gone undetected for so long because of the bewildering variety of colours and shapes the structure adopts. Prud’homme and colleagues say this is evidence of how an organ can grow in unpredictable ways once it is relieved from its original function.
(Image: Nicolas Gompel/Nature)
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