Chasing isopods in CT

-- Rob Buchkowski PhD Student

This was the first summer of my PhD, and it spent a lot of time exploring some of the animals that make up the detritus-based food chain in our old-fields at Yale-Myers forest. The detritus-based food chain includes all the animals that can trace their food back to decaying material like plant and animal litter. Some common examples of species include earthworms, crickets, millipedes, and woodlice.

One of the most common species is Trachelipus rathkii, which is a species of isopod or woodlouse. Isopods are actually crustaceans, but are able to survive on land because they have adapted morphologically and behaviorally to conserve water.  You can identify T. rathkii from the other species in New England quite easily, because it has 5 pairs of lungs on the underside that are quite easy to see. These lungs are used to breath, but area totally different from human lungs. Other isopod species in New England have 2 visible pairs.

I also spent some time looking for another group of detritivores—earthworms! We all know that earthworms are really important in promoting soil nutrient cycling, but I am interested in how there impact on soils might influence plant and animal communities aboveground. I started off this summer by trying to figure out how many earthworms live in our old-fields. To do this, I searched through about 230,000 cm3 of soil to get a reliable estimate of population size. I found that our fields vary from having 125 – 275 m2. This is a lot of earthworms, but not unexpectedly high. This fall, I am hoping to identify the species of earthworms, and work on some more efficient methods for extracting them. 

Finally, I spent some time looking at the predators of these detritus eating species. One common predator is wolf spiders. Wolf spiders eat crickets, isopods, and a number of other soil animals. They also eat insects that feed on plants. Check out this video of a wolf spider eating an isopod!