University of Illinois biologist Jim Nardi really knows how to look through a compost pile. He’s the author of a new book called Life in the Soil: A Guide for Naturalists and Gardeners, and he sent us this utterly cool image as his guest rant. His explanation follows, but meanwhile, we’ve got a copy of Life in the Soil to give away. Tell us about the most interesting thing you’ve ever found underground, bug or otherwise, and the book is yours. And now we turn it over to Jim:
not have the great diversity of soil creatures found on the forest floor of an
old growth forest, but they still have all the major members of a healthy soil
food web. My friend Mark Sturges in Bandon, Oregon recently sent me a cup of
compost from one of his bins, and we set about imaging the inhabitants of this
Quite a crew of organisms participates in decomposing the plant
materials. Beetles such as the primitive carrion beetles (agyrtid
beetles,f) and their larvae (g) along with several species of
scarab (dung) beetles (i, j) help shred and mix the decaying matter.
These beetles are assisted by mites (h) that live as stowaways on beetle
bellies and under beetle wing covers. These hitchhiking mites help their
beetles compete with fly larvae for the coveted decaying matter; mites tag along
to feed on eggs and young larva of flies such as those of soldier flies
(k) and flies related to fruit flies (l).
(a), fungi, potworms [arrows in b point to small potworms,
c shows larger potworms]
and springtails (d) along with a few
earthworms participate in converting compost to humus. Protozoa (arrow in
a) that feed on bacteria (and even some fungi such as the insect-eating
Beauveria shown here (e) on the remains of an agyrtid beetle)
represent the smallest predators of the compost. Nematodes (b) that feed
on the bacteria, fungi, and protozoa represent larger predators.
And in this
bin, the rove beetles (m, n) with their sickle-shaped jaws are the
largest predators. The food web of each compost and garden soil has its own
unique mix of species. Sizes of all organisms are indicated with scale bars
[1000 µm = 1 mm].