Stick and leaf insects are a diverse and strikingly bizarre group of insects with a world-wide distribution, which are more common in tropical and subtropical areas. They are famous for their impressively large body size, compared to other insects, and their remarkable ability to camouflage themselves as twigs, leaves or bark in order to hide from potential predators. A team of international researchers led by the University of Göttingen has now generated the first phylogenomic tree of these insects. The results have been published in the journal Frontiers in Ecology and Evolution.
The most surprising finding is that the relationships between the early emerging groups of stick and leaf insects largely disprove the earlier assumptions. In fact, the genealogy reflects more the geographic distribution than the anatomical similarity of the animals. The authors revealed a New World lineage of purely North and South American species and a group of Old World origin that comprises species from Africa to New Zealand.
The biogeographic history was reconstructed by Sarah Bank, PhD student at the University of Göttingen and coauthor of the study, which resulted in further unexpected results: “The flamboyant stick insects of Madagascar, for instance, descended from a single ancestral species who colonised the island approximately 45 million years ago.”
The age estimation of the phylogenetic tree suggests that most of the old lineages emerged after the dinosaurs became extinct 66 million years ago. Thus, the remarkable camouflage of stick and leaf insects most probably evolved afterwards as adaptation against predatory mammals and birds.
“Stick insects become more and more important as model organisms for evolutionary research. The new comprehensive molecular dataset won’t be exhaustively analysed for quite some time and will provide exciting insights into the function of the numerous detected genes,” explains Bradler with regard to future studies. Paper. (open access) – Sabrina Simon, Harald Letsch, Sarah Bank, Thomas R. Buckley, Alexander Donath, Shanlin Liu, Ryuichiro Machida, Karen Meusemann, Bernhard Misof, Lars Podsiadlowski, Xin Zhou, Benjamin Wipfler, Sven Bradler. Old World and New World Phasmatodea: Phylogenomics Resolve the Evolutionary History of Stick and Leaf Insects. Frontiers in Ecology and Evolution, 2019; 7 DOI: 10.3389/fevo.2019.00345 More.
Of course, they don’t come right out and say this but if the stick insects’ amazing camouflages developed after they started to be eaten by predatory mammals and birds, there was not as much time as was thought for the Darwinian claim:
It may be said that natural selection is daily and hourly scrutinizing, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, wherever and whenever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life.
Once calculation becomes possible, Darwinism will usually fail. Something else is happening.
See also: Unlike the furtive ants, stick insects really have, allegedly, gone a million years without sex
Follow UD News at Twitter!