This post is by Olivia Schouten, one of this year’s Hubbard Fellows. In this post, she writes about the importance of bison and cattle dung in prairie ecosystems – a topic you might not think much about on a daily basis.
When walking through a prairie, or anywhere for that matter, I think most people tend to avoid piles of refuse left behind by critters. While not the most pleasant things to encounter, smell, or step in, scat is an essential part of any ecosystem that many creatures are more than happy to encounter, and in many cases specifically seek out.
While conducting flowering plant surveys at our Niobrara Valley Preserve, I walked through an area of the pasture recently visited by the bison herd and found a couple of organisms making use of the bison pies. First, I found an ornate box turtle square in my path, digging furiously into a half-dried bison pie. Its long, sharp claws efficiently broke away chunks of the pie, revealing to the turtle beetles and other invertebrates attracted to the scat for their own purposes. I think I even heard a crunch when the turtle found something tasty amongst the poo. Considering the number of piles left behind by the bison, I realized just how great a resource these bison pies are to animals like this turtle, as they attract a buffet for easy pickings.
Not long after moving on from the turtle, I found some critters making use of the actual bison scat. Dung beetles are iconic coprophages (excrement eaters), rolling their balls of poop along to feed their larvae, and we have several of our own species right here in Nebraska! These common tumblebugs (Canthon pilularius) had excavated a nice round ball of bison pie, ready to be transported!
Tumblebugs are just one of several species of scarab we have here in Nebraska that make use of animal excrement in much the same way. This colorful rainbow scarab (Phanaeus vindex) visited a cow pie here at the Platte River Prairies.
Here is a very short video clip of the box turtle and tumblebugs feeding.
So next time you come across a pile of poo, consider stopping for a look! You never know what interesting things you’ll find!
Oh man, there are so many choices for titles when writing a blog post about dung beetles…
While my wife and I were hiking around the Niobrara Valley Preserve a few weeks ago, Kim spotted a couple dung beetles rolling a ball of bison dung through the Sandhills. It was really fun to watch them and it was my first good opportunity to photograph dung beetles in action. The light was nice and the beetles seemed fine with me watching them. As it happened, once I started following the first pair with my camera, I ended up seeing two other pairs of beetles within a few yards of the first. I wish I’d had the time to follow them longer and see where they went with their booty.
Dung beetles don’t often get a lot of attention, but when they do, it’s the “rollers” that usually get it. In fact, there are three general categories of dung beetles: rollers, dwellers and tunnelers. Dwellers just live inside manure piles (ick). Tunnelers burrow beneath manure piles and bury some of it for their larvae to feed on (boring). But ROLLERS!! Rollers make a neat round ball out of manure and roll that ball across the ground for our enjoyment. (Oh, and also so they can find just the right place to bury it and lay eggs with it.)
Essentially, rollers, dwellers, and tunnelers are all doing the same job: they feed on manure and help break it down and return it to the soil. Clearly, however, dung beetles that roll poop balls across the ground do that job in the most entertaining way!
To be serious for a moment, there are apparently 50 or so species of dung beetles here in Nebraska, and they really do play a really important role in converting manure into productive soil. Strong populations of dung beetles can also break down manure piles before parasites on cattle and bison can lay their eggs in them – helping to control those parasite populations. Ironically, chemical treatments used to reduce parasite loads in livestock can be hard on dung beetle populations because the pesticides remain in the manure. Even more ironically, some people are now advocating the introduction of dung beetles from other continents to bolster declining populations of beetles in U.S. pastures. Humans sure are silly sometimes.
On the other hand, we don’t roll big balls of poop around…