A famed biologist once said that God must have had “an inordinate fondness for beetles.” He was referring to
the fact that beetles form the largest single order in the entire animal kingdom, with more than 350,000 known
species. Apparently, beetles owe much of this evolutionary success to their eating habits. I’m Jim Metzner and
this is the Pulse of the Planet, presented by DuPont. We know from fossils that beetles have been around for
quite a long time, about 250 million years. According to Brian Farrell, an associate professor of biology of
Harvard University, there’s a good reason why beetles have survived for so long and diversified into so many
different species. It has to do with adapting their diet to the available food source, which for beetles is plants.
“The plants that were around when beetles first started the business of eating plants were non-flowering
plants, things like pine trees and their relatives. It took another hundred million years or so before flowering
plants appeared on the planet. Flowering plants very quickly rose to dominance, and beetles took advantage of
that.”
Beetles also use plants for more than just food. Take bark beetles, for example.
“They basically carve the galleries in logs that we’ve all seen, those intricate, hieroglyphic-like carvings that you
see underneath the bark. The males get in there and they’ll eat some of the plant and they’ll use some of the
resins that the plants exude to attract females, and tell the females that, hey, here’s a good tree to eat, here’s
a good place to start a family.”
And beetles, like some other insects, also use plants to ward off potential predators. Some beetles, for example,
eat poisonous milkweed plants that don’t hurt the beetles but do make them toxic fare for birds and mammals.
Please visit our web site at nationalgeographic.com. Pulse of the Planet is presented by Dupont, bringing you
the miracles of science, with additional support from the National Science Foundation. I’m Jim Metzner.