Colony co-founding in ants is an active process by queens

Abstract

Cooperative breeding may be selected for in animals when, on average, it confers greater benefits than solitary breeding. in a number of eusocial insects (i.e., ants, bees, wasps, and termites), queens join together to co-create new nests, a phenomenon known as colony co-founding. it has been hypothesised that co-founding evolved because queens obtain several fitness benefits. However, in ants, previous work has suggested that co-founding is a random process that results from high queen density and low nest-site availability. We experimentally examined nest-founding behaviour in the black garden ant, Lasius niger. We gave newly mated queens the choice between two empty nesting chambers, and compared their distribution across the two chambers with that expected under random allocation. We found that queens formed associations of various sizes; in most instances, queens group together in a single chamber. Across all experiments, the frequency of larger groups of queens was significantly higher than expected given random assortment. These results indicate colony co-founding in ants may actually be an active process resulting from mutual attraction among queens. that said, under natural conditions, ecological constraints may limit encounters among newly mated queens.

Cooperation by ant queens during colony-founding perpetuates alternative forms of social organization

“…Taken together, our results reveal that polygyne queens are not restricted to dependent colony-founding (Cronin et al 2013 ), but that they also successfully engage in independent colony-founding in nature, which might be a common pattern in monodomous, polygyne species (Hamidi et al 2017 ). Furthermore, field data also revealed that both solitary and cooperative colony-founding occur in the wild, which adds to the growing body of literature showing that cooperative colony-founding is a widespread mode of founding in ants (e.g.Bernasconi and Strassmann 1999 ; Johnson 2004 ; Shaffer et al 2016 ; Gotoh et al 2017 ; Madsen and Offenberg 2017 ; Masoni et al 2017 ; Motro et al 2017 ; Lenancker et al 2019 ; Aron and Deneubourg 2020 ). Although monogyne and polygyne queens founded colonies independently, both solitarily and cooperatively, they differed markedly in their propensity to engage in cooperative colony-founding.…”

Non-kin Cooperation in Ants

“…Queens may also form pleometrotic assemblages by searching out other queens as suggested for some populations of the weaver ant, Oecophylla smaragdina (Peeters and Andersen, 1989;Crozier et al, 2010). It is even possible that queens locate each other using pheromones or other attractants (Aron and Deneubourg, 2020).…”

“…Natural selection will favor traits that lead to pleometrotic associations when the success of independent colony founding (haplometrosis) is very low (Shaffer et al, 2016;Haney and Fewell, 2018); independent colony founding rates are indeed estimated to be less than 1% in many ant species (Hölldobler and Wilson, 1990;Aron and Deneubourg, 2020). The formation of pleometrotic associations would therefore be driven by mutualism; kin selection (i.e., relatedness) would not necessarily play a role.…”

“…That is, the initial associations of unrelated queens persist through colony ontogeny. The proximate mechanisms leading to such associations have been investigated in some ant taxa (Clark and Fewell, 2014;Helmkampf et al, 2016;Overson et al, 2016;Shaffer et al, 2016;Eriksson et al, 2019;Masoni et al, 2019;Aron and Deneubourg, 2020). Despite the initial benefits of primary polygyny, it is believed to be relatively rare for pleometrotic associations to result in permanent polygyny (Hölldobler and Wilson, 1990;Bernasconi and Strassmann, 1999;Eriksson et al, 2019).…”

Queens from a unique hyper-denseLasius nigerpopulation tolerate pleometrosis better than queens from a ‘normal’ population

“…In addition, the limitation of nesting sites may be important for forming pleometrotic groups (d'Ettorre et al, 2005). Pleometrotic groups do not form by chance -in experiments, queens were collected in one chamber when they had several to choose from (Aron & Deneubourg, 2020).…”