[
European Journal of Soil Science,
1998]
The movement of bacterial-feeding nematodes (Caenorhabditis elegans) through sand was investigated using a range of sand sizes, equilibrated at a range of matric potentials, in the presence or absence of an attractant source (Escherichia coli) at the distal end of a column. In the presence of E. coli there was significantly greater movement of the nematode population towards the E. coli population, and the extent of the movement depended on the matric potential of the sand. Over time, an increasing proportion of the C. elegans population responded to the presence of the E. coli. The processes controlling these effects are discussed with respect to taxis and kinesis mechanisms of the nematode population, and with regard to the diffusive characteristics of the physical structure of the sand.
[
Microb Ecol,
2004]
Can diet have a significant impact on the ability of organisms to sense and locate food? Focusing on the bacterial feeder Caenorhabditis elegans, we investigated what effect preconditioning on a range of bacterial substrates had on the subsequent chemotaxis process involved in the nematode locating other bacterial populations. Remarkably, we found that C. elegans, initially fed on a diet of Escherichia coli OP50, was significantly impaired in finding E. coli OP50 populations, compared to other available bacterial populations (P < 0.001). We found similar results for another bacterial feeding nematode species, suggesting that a general "substrate legacy" may operate across a wide range of organisms. We discuss this important finding with respect to the variation in response exhibited within a given nematode population, and the impact nematode migration has on bacterial dispersal in the environment.