Harvester ants that eat weed seeds on the soil's surface can help farmers manage weeds on their farms, according to an international team of researchers, who found that tilling less to preserve the ants could save farmers fuel and labor costs, as well as preserve water and improve soil quality. "These ants are naturally present in the fields," said Barbara Baraibar Padro, a postdoctoral scholar in plant science, Penn State. "They are able to remove a huge amount of weed seeds from the system, and if farms till less to preserve these ants, it can benefit them." Tilling a field disturbs the soil and can destroy ant nests. The researchers wondered whether tilling had an impact on the number, size and distribution of ant nests in the fields, and how these factors could influence the ant's ability to control weeds. "Tilled fields might harbor more weeds because they don't have the pressure from the ants," said Baraibar. "If you don't disturb the soil, you might have more ants." The researchers compared the number and size of ant nests in four tilled fields and three no till fields in Spain. They also marked the locations of different ant nests using GPS, then analyzed how evenly spaced apart the nests were in the tilled and no till fields. Their paper will appear in Biological Control in January 2019. (Source: Agriculture and Food News, ScienceDaily. www.sciencedaily.com)
Messor barbarus ants harvesting and bringing wild oat (Avena fatua) weed seeds to the nest entrance. Soldier ants (with large red heads) and smaller workers are visible. Photo Credit: Barbara Baraibar, Penn State