Predatious Ants Patrol Sweet Potatoes in Cuba

Cuban farmers are using the predatory lion ant (Pheidole megacephala) to control the sweet potato pest Cylas formicarius, which is a beetle. The lion ant is indigenous to Africa, and was probably introduced to Cuba through the slave trade. Lion ants were traditionally used by the small farmers of Cuba to rid the compound of fire ants (Solenopsis geminata). Antonio Casta–eira of the Cuban Institute of Plant Protection adapted this folk practice for the elimination of C. formicarius from sweet potato fields.

Casta–eira devised an ingenious lure to capture lion ants so they could be brought to the sweet potato fields where they were needed. The lure consists of a pile of cut banana stems, stacked like cord wood, and placed in an area where lion ants are naturally abundant. Casta–eira used the stems of banana plants since they are rich in carbohydrates. The lure is covered with a damp cloth to keep it moist, and provided with food scraps to attract the ants. Technicians and assistants check the piles periodically to keep them moist and supplied with scraps. When the ants discover the lure, they move their nest into the banana stems. Colonization takes 3 - 4 weeks.

The stems with lion ants in them are then placed in a field of sweet potato plants infested with C. formicarius after which the ants relocate their nest to the soil. The now- resident lion ant population builds nests around the growing sweet potatoes, preventing C. formicarius from boring into the tubers.

Farmers have found lion ants to be effective at controlling C. formicarius . An economic analysis of the lion ant-sweet potato system demonstrated that it is indeed an economically viable alternative to chemical pest controls.

Lion ants have been used in other cropping systems as well. Researchers in Nicaragua have employed lion ants to control sugar cane borer and beetles in bananas. Lion ants have been used to prevent the establishment of populations of the destructive leaf cutter ant, and to displace stinging ants in citrus groves.

Researchers in Cuba are now investigating other ways of managing the environment of sweet potato fields in order to attract and maintain lion ant populations. They are experimenting with banana plantings near the sweet potatoes to serve as a reservoir for lion ants. Such an innovation would eliminate the considerable labor required to prepare, monitor and transport the banana stem lures and lion ant colonies.

For additional info:

Dr. Richard Levins
Department of Population Sciences
Harvard School of Public Health
665 Huntington Avenue
Boston, MA 02115 USA