Brood sorting by ants: two phases and differential diffusion

Ant-based and swarm-based clustering

“…Annular sorting has been observed in Leptothorax unifasciatus which arrange their larvae as a function of their size (Melhuish et al 2006;Sendova-Franks et al 2004;Scholes and Wilson 2004). The conjectured biological utility of such sorting behavior is increased efficiency in nest care, as the brood is spatially arranged according to its nutritional and metabolic needs.…”

Evolving agent swarms for clustering and sorting

“…Work on computer simulations of brood sorting have also been very limited to this date. Another indication of the difficulty of annular sorting is that the underlying mechanism is still unknown [13]. Despite this, there have been varying suggestions as to what may cause the annular structure in brood sorting.…”

“…Another suggestion is mechanisms based on differential adhesion, and Wilson et al [14] have showed that this can be done with two types of objects. However, brood sorting in Leptothorax ants include five types of objects and Sendova-Franks [13] have therefore found it unlikely for models based on differential adhesion to be satisfactory. Franks and Sendova-Franks [6] suggest that deliberate spacing using pheromones or metabolic waste products may be the underlying mechanism, or the conditional probabilities used by Deneubourg et al [5] combined with packing rules.…”

“…Franks and Sendova-Franks [6] suggest that deliberate spacing using pheromones or metabolic waste products may be the underlying mechanism, or the conditional probabilities used by Deneubourg et al [5] combined with packing rules. Sendova-Franks et al [13] have recently discovered that the brood sorting by Leptothorax has two distinct phases of the direction of brood movement. In the first phase the brood items are moved in a direction away from the nest entrance, and this phase constitutes a clustering phase.…”

“…Influenced by the work of Sendova-Franks et al [13] which found that the brood are first clustered and thereafter spread out to form the annular structure, we have given the compactness component twice the weight of the other two components when they are added together (Equation 6).…”