Assessment of Range Caterpillar (Lepidoptera: Saturniidae) Effects with a Grassland Simulation Model

An empirical consumption submodel for range caterpillar, Hemileuca oliviae Cockerell, which integrated consumption and mortality, was developed. This submodel was used in conjunction with a process-oriented producer submodel and abiotic submodel to assess the effects of various range caterpillar population densities, and heterogeneous environmental conditions, on above-ground and below-ground productivity of blue grama rangeland. Economic injury levels were calculated based on current caterpillar population suppression costs and forage values, and on variable caterpillar population densities and environmental conditions.