Spatial organization in a dimorphic ant: caste specificity of clustering patterns and area marking

Abstract

Living in groups constitutes the root of social organization in animals. Likewise, the spatial aggregation between members of insects societies plays a crucial role in social cohesion and division of labor, namely, in polymorphic ant species. In the present paper, we show caste-specific aggregation patterns in the strictly dimorphic Pheidole pallidula ant species. We investigate the influence on the clustering of ants exerted by direct contacts between nest mates as well as by indirect cues through chemical marking. In a homogeneous environment deprived of chemical cues, majors show a higher aggregation level than minors and a centripetal behavior. By contrast, minors are more scattered in the experimental arena and display a centrifugal behavior. In addition, area marking laid by minors enhances their own aggregative behavior while contributing to the localization of the spontaneously aggregating majors. Such differences in aggregative patterns as well as their adaptive value have to be coupled with the mobility level and the task performance efficiency of each worker caste. Contrary to majors that are likely to aggregate, highly mobile minors, scattered inside and outside the nest colony, can detect colony needs and can carry out most of the daily tasks for which they are more efficient than majors.

Who Are the “Lazy” Ants? The Function of Inactivity in Social Insects and a Possible Role of Constraint: Inactive Ants Are Corpulent and May Be Young and/or Selfish

“…Older workers may potentially be driving the relationship between inactivity and slow walking speed (if senescent workers walk much more slowly than younger workers), but another likely scenario is that the increased corpulence of young reproductive/ replete workers may cause reduced mobility (Sempo et al 2006). Nonetheless, the majority of the inactive task group appears to be younger workers (31 with oocytes vs. 8 without).…”

“…Repletes have been shown to typically be larger than their nestmates (Hasegawa 1993;Hölldobler and Wilson 1990;Tsuji 1990) (but see [Børgesen 2000]), develop and remain inside the nest (Børgesen 2000), typically have reduced mobility (Sempo et al 2006), and do not engage in other colony tasks (e.g., foraging [Kondoh 1968;Porter and Jorgensen 1981] and defensive tasks [Lachaud et al 1992]). In the ant Temnothorax albipennis, workers have been shown to vary in corpulence (typically measured as gaster distension or dry weight, sometimes relative to body size) with season and with age (Blanchard et al 2000;Robinson et al 2009).…”

Impact of increasing deployment of artificial floating objects on the spatial distribution of social fish species

“…Asymmetrical distributions have been theoretically studied and experimentally highlighted in social insects during foraging and aggregation (Camazine ; Jeanson et al . ; Sempo ), in gregarious insects (Halloy et al . ; Sempo et al .…”

“…Those theoretical results are close to experimental and theoretical dynamics previously reported for social species. Asymmetrical distributions have been theoretically studied and experimentally highlighted in social insects during foraging and aggregation (Camazine 2001;Jeanson et al 2004;Sempo 2006), in gregarious insects (Halloy (Farr 1978;Devigne, Broly & Deneubourg 2011) and in vertebrates (Hoare et al 2004;Michelena et al 2010). The shift between selection of a patch and the dispersion due to the increase in the number of patches is reported during ant's foraging activity (Hahn & Maschwitz 1985;Deneubourg et al 1989;Franks et al 1991;Nicolis & Deneubourg 1999).…”

The role of biotic and abiotic cues in stimulating aggregation by larval cane toads (Rhinella marina)

“…Aggregation occurs in organisms ranging from vertebrates to bacteria (Ward & Webster, ), and can entail both costs (e.g., competition for resources and mates, predator attraction, parasite, and disease transmission) and benefits (dilution of predation risk, enhanced foraging, increased vigilance, and predator confusion) (Beiswenger, ; Dall, Giraldeau, Olsson, McNamara, & Stephens, ; Foster & Treherne, ; Hamilton, ; Leu, Whiting, & Mahony, ; Pulliam, ; Sansom, Cresswell, Minderman, & Lind, ; Sontag, Wilson, & Wilcox, ). However, proximate cues for aggregation are poorly understood for many organisms (Sempo, Depickère, & Detrain, ).…”