Comparative Efficacy of Pimephales promelas, Fundulus diaphanus, and Gambusia affinis and Influence of Prey Density for Biological Control of Culex pipiens molestus Larvae

ABSTRACT Larval survival times and density-dependent feeding behavior were evaluated with the use of 2 species of fish native to the northeastern USA (Pimephales promelas and Fundulus diaphanus), and the potentially invasive Gambusia affinis. Each species was provided 10, 20, 30, 45, and 60 4th-stage larvae of Culex pipiens molestus/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 P. promelas, 60 larvae for F. diaphanus, and 36.44 ± 6.6 larvae for G. affinis. 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 P. promelas, 15 ± 3.4 h for F. diaphanus, and 70.6 ±13 h for G. affinis. In order to evaluate f...