No points for guessing what dung beetles eat. Feces are so rich with nourishing bacteria that 80 or more species of the beetle can live in the same area. Under such intense competition for droppings, one species has gone entirely from scavenging to preying. Through 11 months of recording with infrared cameras in the Peruvian jungle, Trond Larsen of Princeton University and his colleagues found that an eight-millimeter-long nocturnal dung beetle, Deltochilum valgum, devours millipedes up to 13 times larger than itself. The beetle kills by wrapping its legs around a victim, wedging its serrated head between the prey's segments and then ripping the body apart. The head of this species is unusually narrow for dung beetles—all the better to burrow inside a corpse to dine on the innards, the researchers note in their report, published online January 21 by Biology Letters.
This article was originally published with the title "A Beetle's Menu Change" in Scientific American 300, 4, 30 (April 2009)