Omnivores: members of the clean plate club
I’ve become interested in the relative impacts of carnivores and omnivores in structuring marine communities. In NC estuaries, omnivores may play a large role in structuring algal communities due to their larger body sizes compared to the relatively small herbivorous amphipods and isopods in this system. In feeding trials our omnivores, largely juvenile pinfish, brown and grass shrimp, and mud and swimming crabs (aka “bait”), turn out to be fairly efficient carnivores. In fact, I’m constantly amazed by the fact that these critters will eat just about anything they can catch and/or fit in their mouth. Today I discovered that a mud crab had wounded and was chasing one of my pinfish, and yesterday I caught a pinfish eating a brown shrimp and a brown shrimp munching on mud crab remnants. And, they’d all eaten every bit of Ulva lactuca I’d put in their tanks, reinforcing my belief that Ulva is simply too tasty for its own good. They’d make my grandpa proud as true members of the ‘clean plate club.’
So what effect does all this predator diversity, omnivore and carnivore, mean for plants? Part of the answer may be in the abundance of herbivores and the distribution of predator biomass between intraguild carnivores and facultative omnivores. My enthusiastic undergraduate technician Michael is on the case. It’s going to be an exciting summer!
P.S. Regarding the Ulva issue of last summer, it was #5, all of the above.
Tangled Transects
Tuesday, July 15, 2008
This is our diversity tank, where we keep a myriad of critters for show and tell. It’s also always the cleanest, prettiest of our tanks. We found everything pictured here at our field sites. I wonder who goes golfing in the marsh...
