A new study reports that a specific species of dragonfly may have an unusual tracheal system in their wings. This could us a fascinating insight into how insect wings evolved. The study was published in the journal Biology Letters, and led by the Federal University of Sao Carlos in Brazil.
Today, most flying insects have large wings with thin membranes. However, it’s thought that the first winged insects more than 300 million years ago may have had living tissue inside wing-like structures. These could have been used to skim or row on water before later insects gained the ability of flight.
Studying this species, the researchers found evidence of those earlier, primitive wings. These were in the form of a tracheal system inside the membrane which, combined with other characteristics of this dragonfly, may account for the notable bright blue design of male wings.
“The origin, development, and dynamics of an intriguing subject in biology, insect-winged flight, is one of the most exciting topics in organismic biology,” the team write in their paper.
“The presence of tracheation of the wing membrane may promote further research to unravel their role and also start the search for similar cases in Insecta.”
This discovery was made by the team using a scanning electron microscope to examine the wings of this dragonfly, also known as a morpho dragonfly. This revealed the skinny and branching tracheal tubes inside the wing.
While insect wings are generally “dead” and lifeless, this study hints that some may actually be much more alive, with living tissue elements inside them.
“Wings of insects start as living tissue, but as the creatures take their adult form, cells die between the strut work of supporting wing veins,” Susan Milius notes for Science News. “The veins, as they’re called, have their own respiratory tubes, nerves and such. But entomologists thought the rest of an insect wing would be no more alive and in need of oxygen than toenail clippings.”
The blue color of morpho dragonflies is quite rare, and this discovery may explain how they achieve the coloration, with oxygen running through the veins. And this might not just be for show – the blue color can intimidate rivals for breeding territory.
Insect wings now are pretty dead. But maybe this remarkable dragonfly can give us an insight into how they first took shape, and tell us more about their modern appearance in the meantime.
(h/t Science News)