PARENT SESSION
Oral Session #60: Agroecology- Sustainable Agriculture.
Presiding: R. Bohanan
Wednesday, August 7. 8:00 AM to 11:30 AM. Mesquite Room, Radisson.

Ants as indicators of pesticide impacts and agroecosystem integrity in banana.

MATLOCK, ROBERT^*,1, ¹ La Selva Biological Station, Puerto Viejo de Sarapiquí, Heredia, Costa Rica

ABSTRACT- To control weeds, root parasitic nematodes, fungal pathogens and insect pests, banana plantations are treated with herbicides, nematicides, fungicides and insecticides. The impact of these pesticides on the organisms within plantations, however, is largely unknown. Ants have been widely used as biological indicators in invertebrate biodiversity assessments. Hence, to evaluate the effects of pesticides on banana plantation invertebrates, ants were surveyed in six conventional plantations treated with the pesticide applications described above and in two low-input plantations that received reduced applications of herbicides, nematicides and insecticides. To put banana into perspective relative to other tropical monocultures, ants in banana were also compared to those in four other crops: citrus, heart of palm, macadamia and Gmelina arborea. A total of 23,364 ants comprising 107 species, 48 genera and 6 subfamilies was collected at the 12 study sites. Ant species richness and abundance in low-input and conventional banana did not differ significantly, but were lower than in the four other crops. Ant species richness and abundance correlated with the richness and abundance of parasitoids collected concurrently from the same sites, but differences among low-input banana, conventional banana and the other four monocultures were more pronounced for parasitoids. Species richness in conventional banana, low input banana and the four other crops was independent of species origin (native or exotic), habitat preference, nest type, diet or ant functional groups sensu Andersen.

KEY WORDS: Ants, Formicidae, Pesticide, Banana