HOUSEHOLD AND STRUCTURAL INSECTS Acceptance and Intake of Gel and Liquid Sucrose Compositions by the Argentine Ant (Hymenoptera: Formicidae)

Liquids and gels are common delivery forms used in commercial ant baits, but the relative effectiveness of each is unknown. We compared the feeding responses of the Argentine ant, Linepithemahumile(Mayr), to liquid andgel compositionsof sucrose. In choice assays,moreworkers were counted on gel than liquid; however, substantiallymore liquidwas consumed. Becauseworkers could stand on the gel, more workers could feed simultaneously on the gel. The feeding bouts of individual workers, however, were much less efÞcient at extracting sucrose in gel form. Workers fed eightfold longer on the gel, yet removed Þvefold less sucrose than workers feeding on liquid. This potential bias should be considered during attraction and palatability studies that use physically different bait compositions. When the toxicant Þpronil was added to the compositions, a greater proportion of the colony died after workers had fed on liquid than gel baits. This Þnding suggests that liquid formulations may provide more effective control of Argentine ants due to the greater speed and abundance in which it is ingested.