Scouting ants as the cognitive elite of the ant hill — ASN Events

Scouting ants as the cognitive elite of the ant hill (#136)

Zhanna Reznikova 1 , Natalia Atsarkina 2 , Ivan Iakovlev 1
  1. Institute of systematics and ecology of animals, Novosibirsk, Russia
  2. A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia

Long term studies revealed strongly stable professional groups in red wood ants such as shepherds, guards, hunters, transporters, and scouts (Reznikova, Novgorodova, 1998; Reznikova, Iakovlev, 2008). What makes an ant scout is still enigmatic. Although sophisticated systems of distant homing are in many respects similar in red wood ants and honey bees (Reznikova, 2008), regulation of scouting completely differs in them. Whereas scouting honey bees change their roles from one foraging trip to another (Beekman et al., 2007), scouting red wood ants perform the same task during several weeks (Reznikova, 2011). To revel distinctive features of scouts, we designed the first battery of behavioural tests which included peculiarities of exploratory activity, levels of aggression and spatial cognition. In order to test exploratory activity, we recorded ethograms of individuals placed in a box with artificial models of natural objects (a “tree trunk”, “grass stems”, a “stone” and a “shelter”). Aggressiveness was estimated from the variety of interactions with ground beetles. The ability to memorize the path was investigated using a binary-tree maze. A significant difference in cognition and behaviour between scouts and foragers was revealed. Both scouts and foragers are more exploratory than “average” out-nest workers, and scouts exceed foragers. In unfamiliar situations scouts more readily switch between different activities. Scouts and foragers displayed nearly equal levels of aggressiveness which are more than in aphid milkers and close to guards. In contrast to guards, both scouts and foragers strongly avoided aggressive actions which may be of danger to themselves, and they never attacked beetles directly. The most distinctive feature of scouts is their high exploratory activity: facing novel items scouts readily advance to explore them. Scouts also form spatial memory faster and keep the information longer and more precisely than foragers. The study has been supported by the Russian Scientific Fund (14-14-00603)