Interactions between the fauna of citrus trees in Trinidad and the ants Atta cephalotes and Azteca sp.
Abstract
In citrus orchards in Trinidad, the presence of the ant Azteca sp. on a tree was negatively correlated with the presence of nests of the termite Nasutitermes costalis (Hlmgr.), but positively correlated with Coccus viridis (Green) and an undescribed species of coccid in the genus Toumeyella. Workers of Azteca deterred Atta cephalotes (L.) from defoliating the host tree. Killing the Azteca with toxic bait resulted in the death of C. viridis and Toumeyella, the arrival of predacious coccinellids in the genus Azya, and the rapid defoliation of the tree by Atta cephalotes. A. cephalotes was observed defoliating citrus trees only 72 h after baiting. Radiolabelled bait, spread from the single tree infested by Azteca to which it was applied to a whole group of trees bearing Azteca, indicating that this species is polydomous. To a limited extent, Dolichoderus bidens (L.) also protected citrus from Atta, its nest usually occupying a single well-flushed bough on an otherwise defoliated tree. The presence of Azteca sp. on citrus trees has thus both advantages and disadvantages for the farmer.