Two cool papers out this week–one on the adaptive radiation of beetles, and the other on assassin bugs and their lovely habit of decorating themselves with the corpses of their prey.
The Other 95% did a great job of covering the bugs, so I’ll talk more about the beetles. What a huge project this must have been! They compiled genetic data from subfamilies containing most of the identified species of beetles (95%). (edited 12/21 to clarify)
Beetles have long been known as an example of a massively diverse group. Almost 25% of ALL described species on earth are beetles. Asked what could be inferred about the work of the Creator from a study of his works, the British scientist J.B.S. Haldane is reported to have replied that he had “an inordinate fondness for beetles.” (also the title of a lovely beetle book, BTW.)
So…why are there so many beetles? That’s what this paper hoped to explore. Most of the existing superfamily groups were supported in this paper as being monophyletic, but explaining how they then diverged into the many different species was a bit difficult. Different hypotheses didn’t quite pan out (phytophagous vs. non-phyt driving speciation, tracking of angiosperm radiation, etc.).
They eventually decided multiple factors drove the amazing diversity of the Coleoptera:
“the extreme diversity of beetles reflects the Jurassic origin of numerous modern lineages, high lineage survival, and the diversification into a wide range of niches, including the utilization of all parts of plants. These switches into new niches occur repeatedly as, for example, the multiple shifts from terrestrial to aquatic habits in the evolutionary history of beetles, which occurred at least 10 time.”
Neat! Full citation:
Hunt, et al. 2007. A Comprehensive Phylogeny of Beetles Reveals the Evolutionary Origins of a Superradiation. Science 21 December 2007: Vol. 318. no. 5858, pp. 1913 – 1916.
Image courtesy of emblatame–check out the lovely big original.