Comparative Efficacy of , , and and Influence of Prey Density for Biological Control of Larvae.

Larval survival times and density-dependent feeding behavior were evaluated with the use of 2 species of fish native to the northeastern USA ( and ) and the potentially invasive . Each species was provided 10, 20, 30, 45, and 60 4th-stage larvae of /fish in the laboratory and digital images were recorded to quantify the number of surviving larvae at various intervals. Daily feeding rates were greatest at the highest larval density. These were 49.69 ± 4.07 larvae for , 60 larvae for , and 36.44 ± 6.6 larvae for . Survival analysis was used to compare efficacy of each fish species over time. All fish species consumed larvae at similar rates at lower densities, but significant differences occurred at densities of 30-60 larvae/fish. Survival times of larvae at the highest density were 44 ± 7.9 h for , 15 ± 3.4 h for , and 70.6 ±13 h for . In order to evaluate feeding rate as a function of prey density, we compared consumption rates 1.5 h after feeding with the use of a 4-parameter logistic model. and feeding aligned with the 4-parameter model, indicating that initial feeding rates for these species increased with prey density to an upper limit (satiation). feeding within 1.5 h did not align with this model, suggesting that early feeding rates for this species are not heavily influenced by prey density.