A study by Yoshinori Tomoyasu, assistant professor of zoology at Miami University, and colleagues provides insight into the evolution of beetles. Their study, published in the Dec. 29 issue of Current Biology, reveals extensive conservation of the wing gene network between the coleopteran (beetle) Tribolium, and the fly, Drosophila, even after 300 million years of separation of these two lineages.
The study ﬁndings suggest that beetle evolution has been achieved by co-opting a beneﬁcial trait several times while conserving the main framework of wing patterning genes.
The evolutionary process of co-opting occurs when natural selection finds new uses for pre-existing traits, such as the cuticle hardening process, says Tomoyasu.
“A message we have learned from this study and others is that evolution seems to be very ‘conservative,’ adding some new features with keeping a core developmental mechanism fairly intact. This might be true for many other evolutionary processes, including the evolution of humans.”
Coleoptera (beetles) is the most successful animal group on the planet, accounting for over 20 percent of extant animals, according to the study authors. An important trait in the successful radiation of beetles is the presence of highly modiﬁed and hardened forewings – the elytra - used as a body cover.
The study revealed the wing gene network defined in flies is largely conserved in beetles even after 300 million years of separation of fly and beetle lineages.
“The fly wing gene network is also used to pattern the elytra, despite the extensive evolutionary modiﬁcation that has occurred in the beetle forewings,” Tomoyasu explains.
Tomoyasu’s research, “Repeated Co-Options of Exoskeleton Formation during Wing-to-Elytron Evolution in Beetles,” is available online [Current Biology (December 2009), doi:10.1016/j.cub.2009.11.014].
Authors are Tomoyasu and Yasuyuki Arakane, Karl Kramer and Robin Denell from Kansas State University.
The work was supported by grants from the National Science Foundation and the Japanese Society for the Promotion of Science.
Tomoyasu joined Miami in 2008.