The industrious, poop-grubbing dung beetles might not have a fancy job, but it turns out they evolved eating the rarified poop of the dinosaurs.
Around 6,000 members of the Scarabaeidae family can be found on every continent except Antarctica, and a new study suggests they showed up on the scene between 115 and 130 million years ago during the Early Cretaceous Period. This means these poop scavengers evolved just around the time as flowering plants, and that's also the same time that dinosaur crap started getting really nutritious.
Flowering plants, or angiosperms, are less fibrous and contain more nutrients than gymnosperms, ferns, cyads, and other types of plants common during the Age of the Dinos. Their rise in ancient ecosystems drove diversification among lots of groups of animals; pollination gave insects a new niche to inhabit, and the plants themselves provided a great new food source for vertebrates — especially dinosaurs, the large animals who really shaped the ecology of the Cretaceous.
And as unsavory as their lifestyle and dietary habits might seem, dung beetles — which today tend to prefer the scat of omnivores — are no dummies. The poop of an animal who has been eating angiosperms is actually a great source of organic nutrients, as well as a relatively safe place to hang out and lay eggs (if you can stand it). After all, who's going to come hassle you and your coprophagous babies in a pile of turds?
Before now, it's been assumed that dung beetles co-evolved with mammals, since the extinction of non-avian dinosaurs would have dealt a big blow to any animal dependent upon dinosaurs in the ecosystem. But the research team, who sequenced the DNA of 450 dung beetle species, found that the major diversification in these beetles happened around 30 million years before the dinosaurs bought the farm, which means they most likely got their start holing up in dinosaur crap.
Nobody knows quite how dung beetles survived the extinction of the dinosaurs, but the research suggests modern dung beetles are descended from species who either fed exclusively on Cretaceous mammal dung, or just weren't picky about whose poop they ate.
Want to learn more about these amazing insects? Watch this video from our Stuff to Blow Your Mind team: