Evolutionary biologists are exploring how ants learn from their experiences. Following an attack from ants of a certain nest, these ants tend to show increased aggression towards others from that same nest.
A research team, headed by evolutionary biologist Volker Nehring, is examining how much ants learn from their experiences.
Ants are capable of learning from their past. This has been confirmed by a team from the University of Freiburg, led by Dr. Volker Nehring from the Evolutionary Biology and Animal Ecology group, along with doctoral candidate Mélanie Bey. In their experiments, ants were repeatedly exposed to competitors from a different nest. The ants recalled the negative experiences from these encounters: when they faced ants from a nest that had previously been aggressive toward them, they reacted more aggressively compared to when they met ants from unfamiliar nests. Conversely, ants that had only interacted with members from a nest known for being passive displayed lower levels of aggression. Their findings were published in the journal Current Biology.
Ants Display Aggression Towards Nearby Competitors
Ants use scent to identify members of their own nest versus those from others. Each nest possesses a unique odor. Previous investigations have revealed that ants often exhibit aggressive behavior particularly towards their closest neighbors, frequently opening their mandibles to bite or spraying acid to eliminate rivals. Such aggressive acts are less likely directed at nests located further away. Until now, the reason behind this behavior was unclear. Nehring’s team has now established that ants remember the scent of their attackers, which accounts for their heightened aggression towards familiar competitors.
Increased Aggression Towards Familiar Competitors
The researchers conducted their study in two stages. The first stage involved different groups of ants having various encounters: one group met with fellow nest members, the second interacted with aggressive ants from rival nest A, and the third dealt with aggressive ants from rival nest B. Altogether, they had five encounters over consecutive days, with each interaction lasting one minute.
In the following testing phase, the scientists observed how ants from different groups acted when faced with competitors from nest A. Those that had prior encounters with ants from this nest in the first phase showed significantly more aggressive behavior than members of the other two groups.
To determine to what extent the heightened aggression derives from experiences with particular nests, the scientists altered the experiment’s design. In the first phase, they distinguished between encounters with aggressive and passive ants. By cutting off the antennae of one ant, they ensured its behavior was passive. In the second phase, the ants that had previously only encountered passive competitors responded with marked reductions in aggression.
“People often perceive insects as acting like robots with set programs,” says Nehring. “Our research offers new proof that ants learn from their experiences and can even harbor resentment.” Moving forward, Nehring and his team plan to investigate whether and how ants tailor their olfactory receptors based on their experiences, thus reflecting their learning at this sensory level as well.
- Mélanie Bey pursued her doctorate under Dr. Volker Nehring. Rebecca Endermann, Christina Raudies, and Jonas Steinle are former bachelor’s and master’s students from the Evolutionary Biology and Animal Ecology group.
- The research received funding from the German Research Foundation (project number NE1969/6-1).
