No. 113/2021

They travel the world unnoticed on ships or lorries, hidden in the earth in a flowerpot or in a crate full of fruit. The spread of invasive ant species is almost impossible to prevent. But in alien ecosystems, they can cause huge damage because indigenous species have not learned to protect themselves against them. The behavioural biologist Tomer Czaczkes investigates how Argen- tine ants make decisions. He would like to find out whether and how you could use expectation management to outsmart invasive ants. To this end, for the first time, he incorporates their cognitive abilities. “With people, we are very good at using psychological tricks to make them buy things they don’t really need or even want,” he says. He is searching for similar mechanisms in invasive ants, such as making them carry food laced with poison into the queen ant’s colony instead of leaving toxic food well alone. In the end, the only remedy for inva- sive ants is to get rid of them again, Czaczkes explains. In one experi- ment, he already ascertained that when ants find food with a lower sugar content than they had expected, they stop feeding and deposit fewer pheromones with which to attract other ants, or none at all. But when they find food with an unexpectedly high sugar content, the very opposite happens and the ants deposit their scent particularly strongly. “Just like humans, ants can apparently experience enthusiasm and frus- tration,” says Czaczkes. “I want to find out whether we could utilise psychological effects like these to fight against invasive ants.” Text MARLENE HALSER DR TOMER CZACZKES became a Humboldt Research Fellow at the University of Regensburg in 2013. He now heads a junior research group there, having been awarded an ERC Starting Grant in 2020. HOW DO YOU INTEND TO OUTSMART INVASIVE ANTS, MR CZACZKES? Photo: Humboldt Foundation/David Spaeth BRIEF ENQUIRIES 8 HUMBOLDT KOSMOS 113/2021