The Presence of Spissistilus festinus as a Factor Affecting Egg Predation by Ants in Soybeans

Abstract

Five ant species, of which Solenopsis geminata (F.) and Conomyrma insana (Buckley) were the most abundant, tended nymphs of the three-cornered alfalfa hopper, Spissistilus festinus (Say), on soybeans in a north Florida field. The presence of nymphs tended by ants was examined as a factor affecting predation on eggs of the soybean looper, Pseudoplusia includens Walker. Where S. geminata tended the nymphs, the percentage of looper eggs missing after 24 hr was significantly greater from plants with nymphs (77.1%) than from plants without nymphs (36.8%). Where C. insana tended the nymphs, the percentage of eggs missing was significantly greater from plants with nymphs than from plants without nymphs after 4 hr (36.8% vs. 17.5%) and 8 hr (65.6% vs. 42.9%), but not after 24 hr (90.7% vs. 86.3%). In all experiments, the proportion of eggs missing was greatest from the lowest 1/3 of the plant and least from the upper 1/3.