Just What do Spiders Eat?
In a previous journal, I mentioned that the wolf spider is a generalist predator that feeds on detritivores in the soil. There are many different organisms that fall under the category of “detritivore,” but by far the cutest (that’s right, I said cutest) are the collembolans. Slugs – not cute. Collembolans? Cute.
I mean honestly. How cute is this guy? Image from bugguide.net
Collembolans are small. REALLY small. Sometimes you can see them walking around the soil, but generally you can’t unless you look very closely – they are typically about the size of the period at the end of this sentence. Well, maybe a teensy bit bigger, but not much. So how do we get an idea (not just an idea, an accurate count) of how many of these little guys are in the soil? Well, recall that a few days ago, Amanda cut slices of the tundra to take back to her lab to analyze. The first step in this analysis was drying out the soil to force the soil organisms into a collection jar (the Berlese method). The second step is to take those collection jars and look at the liquid under the microscope and count the number of organisms in each sample.
Sample collected from Plot 5, Mesocosm 6, surface. The tiny dots in the bottom of the cup are soil organisms.
Close up of a below ground sample.
Kiki scans a sample and records the number and type of organisms she finds.
Since most of us don’t have access to all of the equipment to view the collembola this way, here’s a video by the inimitable David Attenborough showing just how cute these guys really are. Too bad they get eaten by spiders up here in the tundra. Oh, I did I mention they are carnivores? Shhhhh....forget I said anything.