Assimilation and Toxicity of Boron in the Argentine Ant (Hymenoptera: Formicidae)

Assimilation of boron by Argentine ants, Linepithema humile (Mayr), fed boric acid—sucrose water solutions was affected by the addition of sorbitol. Concentrations of 10 and 20% sorbitol reduced boron assimilation by 38 and 67%, respectively, thereby significantly reducing the toxicity of the solutions. The effect of solution pH on mortality indicated that the ionized borate molecule was less toxic than the neutral boric acid species. Electron microscopy revealed that ants fed low concentrations of boric acid (0.5%) show gross abnormalities in the microvilli and cells lining the midgut.