New fossils found in Northeastern China have revealed a remarkable evolutionary coincidence: an extinct group of insects known as Kalligrammatid lacewings (Order Neuroptera) share an uncanny resemblance to modern day butterflies (Order Lepidoptera). Even though they vanished some 50 million years before butterflies appeared on earth, they possess the same wing shape and pigment hues, wing spots and eyespots, body scales, long proboscides, and similar feeding styles as butterflies.
A photo of the modern owl butterfly (“Caligo Memnon”) shown beside a fossilized Kalligrammatid lacewing (“Oregramma illecebrosa”) shows some of the convergent features independently evolved by the two distantly-related insects, including wing eyespots and wing scales. (Butterfly photo by James Di Loreto/fossil photo by Conrad Labandeira and Jorge Santiago-Blay)
In an incredible example of convergent evolution, both butterflies and kalligrammatids evolved the same physical characteristics at vastly different times and while feeding on disparate plant hosts, explains Conrad Labandeira, paleobiologist at the Smithsonian’s National Museum of Natural History. Kalligrammatids had an intricate feeding and pollinating relationship with non-flowering gymnosperms during the mid-Mesozoic; butterflies, by contrast, feed on and pollinate flowering angiosperms. Yet both major groups of seed-plants placed similar selective pressures on the two, unrelated pollinator lineages causing them to develop the same suite of physical and behavioral features.
Labandeira is lead author of a Feb. 3 paper on this discovery in the journal Proceedings of the Royal Society: B.
“Kalligrammatid lacewings are an extinct, Eurasian insect group that has been known to science for a century, but early fossils were fragmentary and not much could be learned from them,” Labandeira explains. New, well-preserved kalligrammatid fossils found between 2004 and 2012 in Middle Jurassic and Early Cretaceous lake deposits of Northeastern China revealed the features of this butterfly look-alike.
Finely deposited lake sediments preserved the insects to a remarkable degree. During their study, the scientists were able to closely examine the fossil surfaces using light microscopy, scanning electron microscopy, electron dispersion microscopy and time-of-flight–secondary ion mass spectrometry to try and characterize molecules left behind by different parts of the insect’s bodies.
A photo of the modern owl butterfly (“Caligo Memnon”) shown beside a fossilized Kalligrammatid lacewing (“Oregramma illecebrosa”) shows some of the convergent features independently evolved by the two distantly-related insects, including wing eyespots and wing scales. (Butterfly photo by James Di Loreto/fossil photo by Conrad Labandeira and Jorge Santiago-Blay)
Read more at Smithsonian News.