An energy budget for the free-living nematode Pelodera (Rhabditidae)

Area of Science:

• Ecological Energetics
• Microbial Ecology
• Nematode Biology

Background:

• Free-living nematodes are crucial in soil ecosystems.
• Understanding their energy budget is key to soil health.
• Pelodera sp. is a common bacterial-feeding nematode.

Purpose of the Study:

• To determine the energy budget of Pelodera sp. feeding on Escherichia coli.
• To investigate the influence of bacterial concentration on energy flow.
• To extrapolate laboratory findings to a bog soil environment.

Main Methods:

• Laboratory experiments with 14C-labeled E. coli.
• Measurement of nematode population growth, respiration, and feeding rate.
• Calculation of energy ingestion, respiration, excretion, and growth.

Main Results:

• Pelodera sp. ingested 37.0×10⁻² J h⁻¹ mg⁻¹ dry weight.
• Respiration accounted for 13.7×10⁻² J h⁻¹ mg⁻¹, excretion for 15.0×10⁻² J h⁻¹ mg⁻¹, and growth for 8.3×10⁻² J h⁻¹ mg⁻¹.
• Energy flow efficiency varied with bacterial concentration.

Conclusions:

• Bacterial concentration significantly influences energy transfer in Pelodera nematodes.
• The study provides a detailed energy budget for bacterial-feeding nematodes.
• Results inform ecological models of soil nutrient cycling.