A Shrimp's Tiny Little Cousin

Here's a neat little critter from this morning's jaunt at Gander Mt.:

Woodlouse (Oniscidea), Gander Mt. FP, Lake Co, IL  4/19/2014

This is a Woodlouse, in the order Isopoda, suborder Oniscidea. They're crustaceans, which means that despite being entirely terrestrial, they breathe through gills. This means that they're limited to moist environments - typically forest soil and decomposing wood. (This one was underneath a fallen log.) They are abundant, and several species are affectionately known by kids as Roly-Polies, for their ability to roll into a ball when disturbed.

They are entirely harmless decomposers, feeding on fallen plant material. Escher, et al. took advantage of their abundance to test differences in the differences in decomposition between Bt transgenic corn and non-transgenic corn. They did find differences in the breakdown rate of several compounds, but the results were a mixed bag: lignin broke down more rapidly in the transgenic plants, simpler carbohydrates in non-transgenic plants. The woodlice showed no differences in feeding rates between the two strains, and reproductive rates were similar, but they gained weight faster and had higher juvenile survival rates when fed transgenic corn. (1)

 Paoletti & Hassall examined how well woodlice could be used to examine nutrient and pollutant levels in agricultural settings. They found that their abundance, ease of both capture and identification, and sensitivity to pesticides and other pollutants make them excellent candidates. (2)

Such a humble little critter to serve such a lofty purpose!



(1) Escher, N., Käch, B., & Nentwig, W. (2000). Decomposition of transgenic< i> Bacillus thuringiensis</i> maize by microorganisms and woodlice< i> Porcellio scaber</i>(Crustacea: Isopoda). Basic and Applied Ecology, 1(2), 161-169.

(2) Paoletti, M. G., & Hassall, M. (1999). Woodlice (Isopoda: Oniscidea): their potential for assessing sustainability and use as bioindicators. Agriculture, ecosystems & environment, 74(1), 157-165.