Abiotic and biotic controls on the abundance and distribution of entomopathogenic nematodes in tallgrass prairie.
DECRAPPEO, N.M* and D.HWALL
Colorado State University, Fort Collins, CO 80523 USA 1
Research on entomopathogenic nematodes has been largely limited to their use as biological control agents in agricultural systems. Little is known about their role in an ecological context, for example, how their abundance, distribution and diversity is affected by abiotic (soil texture, moisture, temperature) and biotic factors (availability and diversity of insect hosts, the presence or absence of soil predators). We investigated these and related questions at the Konza Prairie Long Term Ecological Research site, a tallgrass prairie in eastern Kansas. Specifically, we attempted to elucidate the effects of aboveground plant diversity and the resultant insect abundance and diversity on the abundance and distribution of entomopathogenic nematodes. Utilizing the established burn regime at Konza, we baited and sampled for nematodes at 2 m intervals along elevational gradients in plots burned every 1, 4, and 20 years. The vegetation on these plots is strikingly different: annually burned plots are comprised of a monoculture of Andropogon gerardii,while 4 and 20 year plots consist of a diverse community of grasses, forbs, and woody species. Entomopathogenic nematodes were expected to be more abundant on sites with higher plant diversity due to a greater availability of insect hosts at those sites. After preliminary sampling, we recovered one species of Heterorhabditidae from 20 year plots and no nematodes from annually burned plots. These preliminary findings suggest that plant diversity and correlated insect abundance and diversity may affect patterns of entomopathogenic nematode abundance and distribution in tallgrass prairie.
Keywords: entomopathogenic nematodes, plant diversity, insect diversity, Konza Prairie LTER
This abstract is being presented at: 3:30 PM in session: