Why are there so many more species of insects? Because insects have been here longer

Apr 03, 2007

J. B. S. Haldane once famously quipped that "God is inordinately fond of beetles." Results of a study by Mark A. McPeek of Dartmouth College and Jonathan M. Brown of Grinnell College suggest that this fondness was expressed not by making so many, but rather by allowing them to persist for so long.

In a study appearing in the April issue of the American Naturalist, McPeek and Brown show that many insect groups like beetles and butterflies have fantastic numbers of species because these groups are so old. In contrast, less diverse groups, like mammals and birds, are evolutionarily younger.

This is a surprisingly simple answer to a fundamental biological puzzle. They accumulated data from molecular phylogenies (which date the evolutionary relationships among species using genetic information) and from the fossil record to ask whether groups with more species today had accumulated species at faster rates. Animals as diverse as mollusks, insects, spiders, fish, amphibians, reptiles, birds, and mammals appear to have accumulated new species at surprisingly similar rates over evolutionary time.

Groups with more species were simply those that had survived longer. Their analyses thus identify time as a primary determinant of species diversity patterns across animals. Given the unprecedented extinction rates that the Earth's biota are currently experiencing, these findings are also quite sobering. We are rapidly losing what it has taken nature hundreds of millions of years to construct, and only time can repair it.

Citation: Mark A. McPeek and Jonathan M. Brown, "Clade Age and Not Diversification Rate Explains Species Richness among Animal Taxa" The American Naturalist, volume 169 (2007), pages E97–E106 DOI: 10.1086/512135

Source: University of Chicago

Explore further: Mass deaths of rare Kazakhstan antelopes stir conservation fears

Related Stories

California beaches reopen after goo cleanup

22 minutes ago

Seven miles of Southern California beach shut down for three days by an invasion of oily goo were reopened Friday evening after health officials declared the sand and water safe following a cleanup.

Self-folding robot walks, swims, climbs, dissolves

27 minutes ago

A demo sparking interest at the ICRA 2015 conference in Seattle was all about an origami robot that was worked on by researchers. More specifically, the team members are from the computer science and artificial ...

Recommended for you

Insect mating behavior has lessons for drones

15 hours ago

Male moths locate females by navigating along the latter's pheromone (odor) plume, often flying hundreds of meters to do so. Two strategies are involved to accomplish this: males must find the outer envelope ...

Bacterial tenants in fungal quarters

May 29, 2015

Ludwig Maximilian University of Munich researchers have sequenced the genome of a bacterial symbiont hosted by a mycorrhizal fungus. Analysis of the symbiont's genetic endowment reveals previously unknown ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.