Jurassic lacewings demonstrate leaf mimesis
|September 13, 2010||Posted by David Tyler under Intelligent Design|
The ability of some insects to imitate the leaves and stems of plants has fascinated collectors and researchers alike. Wings, legs and other body parts can all contribute to a very effective disguise, a phenomenon known as mimesis. There has been speculation, of course, about the adaptive origins of the observed characters, but very little data is available on which to build anything robust. The fossil record is meagre. The earliest example before this year has been the Eocene leaf insect Eophyllium, already fully formed and functional (noted here). It conveyed no evidence to support a gradual transformation model. Since living examples of leaf mimesis relate to angiosperm plants, it has been inferred that leaf mimesis is a trait that post-dates the appearance of angiosperms in the Cretaceous.
“Given the phylogenetic placement of these families and genera among their respective orders, such mimicry of angiosperm models likely appeared subsequent to (rather than along with) the radiation of flowering plants. Accordingly, it has been considered that leaf mimesis is a mid-Cretaceous or younger phenomenon.”
However, new research changes this perception. The findings concern lacewings – a group not known for exhibiting leaf mimesis. The fossil specimens come from the late Middle Jurassic, which is significant because this was a period of Earth history before angiosperms appeared and before they became dominant. The plants then were gymnosperms and many of them had pinnate leaves.
blockquote>”Two extraordinary fossil lacewings, Bellinympha filicifolia [. . .] and Bellinympha dancei [. . .] from the Jiulongshan Formation in northeastern China, preserve wings that are dramatically modified to resemble pinnate leaves.”
For more, go here.