Enough of This S#%t! Dung Beetles Morph into Millipede-Eaters

By Nina Bai | January 21, 2009 4:13 pm

dung beetleIt’s hard to get any respect when you eat feces. Maybe that’s why one species of lowly dung beetle has forsaken its namesake for a more glamorous place on the food chain—that of a ferocious carnivore. The species Deltochilum valgum may look like any other dung-roller, but it has adapted to feed on giant millipedes more than ten times its size—for comparison, picture a house cat taking down and subsequently devouring an anaconda.

When rumors of Peruvian dung beetles eating millipedes started floating around, a research team led by Trond Larsen of Princeton University headed to the Peruvian rainforests to see for themselves. After setting up more than 1,000 beetle traps baited with either dung, fungus, fruit, or millipedes in various stages of life and death, they found that D. valgum‘s food of choice is in fact injured millipedes. When D. valgum finds an injured millipede, it uses its powerful hind legs—originally adapted for rolling neat balls of dung—to grasp the millipede’s body. After the millipede finishes flailing about, the beetles uses its sharp teeth to saw between its prey’s body segments, sometimes decapitating it. The corpse is then dragged to a safe location where the beetle devours the soft inner tissue.

How does a species make the jump from scavenger to predator? The scientists note that many dung beetles are attracted to dead insects because of their cyanide-rich odors, so D. valgum‘s carnivorous habits may have developed simply because their ancestors were too impatient to wait for dinner to die. As team member Adrian Forsyth explains to BBC News, “This is a beetle which says: ‘It doesn’t matter if it’s dead or alive, I’m going to eat it.'”

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Image: flickr / DavidDennisPhotos.com

  • http://www.jonathannguyen.net Jonathan Nguyen

    Nina, I have been reading this blog for a while now and the tongue in cheek approach has not gone unnoticed. :)

  • Val

    I came across this whilst looking up what, if anything, preys on millipedes.

    Here in the Mani, southern Greece, we have a type of millipede which sometimes reaches plague proportions and I’m interested to find out why. After reading this blog, I wonder whether it has anything to do with the cycle of animal grazing here. This area is mainly agricultural and touristic, and I am surrounded by olive groves, with garrigue and maquis close by , with scrub oak etc. The olive groves are grazed by the odd donkey and pony, but mainly by beef cattle which are hobbled and herded. Lower down, nearer sea level, there are flocks of sheep and some goats. There are also many foxes and some jackals in the small gorges around. Whilst walking my dog or plant-hunting, I see many dung beetles rolling their dung balls across the paths.

    The millipedes we have are long and black and they smell awful, especially if accidentally trodden on. They get everywhere in the house, and I have even woken up to find one crawling over my face! The adults lay their eggs everywhere, and one night I came home from a night out, switched on my bedroom light and found the window wall black with newly hatched young. The previous year, my daughter and I swept millions of them from the balcony ceilings.

    In the last few years, numbers have declined. I think that the numbers of grazing animals has increased as the population has grown enormously and there is a big demand for local meat.

    Any comments gratefully received!


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