Individual and collective problem-solving in a foraging context in the leaf-cutting ant Atta colombica

Abstract

In this paper we investigate the Xexibility of foraging behavior in the leaf-cutting ant Atta colombica, both at the individual and collective levels, following a change in the physical properties of their environment. We studied in laboratory conditions the changes occurring in foraging behavior when a height constraint was placed 1 cm above part of the trail linking the nest to the foraging area. We found that the size and shape of the fragments of foraging material brought back to the nest were signiWcantly modiWed when the constraint was placed on the trail: independent of their size, forager ants cut smaller and rounder fragments in the presence of a height constraint than in its absence. This size adjustment does not require any direct sensory feedback because it occurred when the ants cut fragments in the foraging area; no further cutting was done when they encountered the constraint. This points to the existence of a template that ants store and use as a reference to adjust their reach while cutting. Remarkably, despite the decrease in the foraging material brought to the nest per capita the colony was still able to improve its foraging performance by doubling the number of transporters. This study illustrates the Xexibility of foraging behavior exhibited by an ant colony. It provides a rare example of insects Wnding an intelligent solution to a problem occurring in a foraging context, at both the individual and collective levels.

The energetics of running stability: costs of transport in grass-cutting ants depend on fragment shape

“…It has been argued that the selection of smaller leaf fragments was favored during evolution because of the underground processing rates of the fragments after their delivery, which are maximal for fragments of intermediate size (Burd and Howard, 2005) (but see Roces and Bollazzi, 2009). Load transport rates may also depend on environmental conditions, such as trail gradients (Lewis et al, 2008), height constraints (Dussutour et al, 2009) and fallen branches (Farji-Brener et al, 2007). The relationship between load size and transport rates is likely to be affected by these factors and hence may influence the ants' decisions.…”

Catalog Learning: Carabid Beetles Learn to Manipulate with Innate Coherent Behavioral Patterns

“…The concept of innate template is rooted in early psychological experiments on fear conditioning in a human infant (Watson and Rayner, 1920). Furthermore, the presence of an innate template has been demonstrated in a great variety of species, from monkeys (Mineka, Keir, and Price, 1980) and humans (Rakison and Derringer, 2008;Soares, 2012) to ants (Dorosheva and Reznikova, 2006;Dorosheva, Yakovlev, and Reznikova, 2011;Dussutour, Deneubourg, Beshers, and Fourcassié, 2009). However, in our situation, avoidance of the dangerous section of the maze was only one (and relatively rare) out of a set of coherent behavioral patterns used by beetles to avoid the unpleasant event.…”

Two castes sizes of leafcutter ants in task partitioning in foraging activity

“…In Attini ants, task partitioning is particularly evident in their foraging activities, including finding, cutting and transporting leaves (FOURCASSIE et al, 2010) These three tasks must be carried out as an integrated process, which requires complex interrelationships among individual ants (BURD & ARANWELA, 2003;DUSSUTOUR et al, 2009;FOURCASSIE et al, 2010). Factors such as distance to food sources, properties of the terrain and quality of available resources may affect the demands imposed by these tasks and the need for inter-individual interactions (LOPES et al, 2003;RÖSCHARD & ROCES, 2003a, 2003bCLARK, 2006;LEWIS et al, 2008;MOLL et al, 2012).…”