Reactions of the lemon leaf-cutting ant, Atta sexdens rubropilosa Forel, to natural sources of allelochemicals has been investigated at the University of Southampton. A linear hypothesis model in a randomized block design of a factorial experiment was utilized to assess the responses of the ants to the treatment combinations. When workers were offered flowers and leaves of the specified plant species simultaneously with mesocarp and endocarp of orange, they exhibited a consistent preference for the flowers. Flower fragments comprised 93.64% of the experimental material brought to the nest, leaves 6.20%, orange mesocarp 0.04% and orange endocarp 0.12%. Deterrent effects were noticed in leaves of Scilla spp. (Liliaceae) and the ants were chemically stimulated to explore, cut and transport the highly attractive flowers of Mahonia aquifolium (Berberidaceae).