Colony size

(see also several reviews at the top of this page under ‘Overview articles’)

We find that larger Temnothorax colonies, like those of other ants, have lower mass-specific metabolic rates; with their lower brood production, this suggests lower efficiency. We also find that density increases metabolic rate.

Cao TT, Dornhaus A 2012 ‘Larger laboratory colonies consume proportionally less energy and have lower per capita brood production in Temnothorax ants’, Insectes sociaux 60: 1-5 - pdf - we found colony metabolic rate scales with colony mass (!) to the 0.78 power and brood number scales with worker number (!) to the 0.49 power (i.e. ‘colony size’ here is measured as two different things). All colonies were controlled for density (i.e. had the same area per weight of colony contents - workers, queens, and brood - available in the nest).

Cao TT, Dornhaus A 2008 'Ants under crowded conditions consume more energy' Biology Letters 4: 613-615 - pdf - when reducing the intra-nest space available to Temnothorax rugatulus colonies in the lab, their colony-level metabolic rate increased.

colony personalities

Temnothorax ant colonies in habitats with high nest site competition invest more in sexuals (reproduction) and less in growth (new workers), and this correlates with a suite of behavioral traits - a life history syndrome at the colony level.

Bengston SE, Dornhaus A 2014 'Be meek or be bold? A colony-level behavioural syndrome in ants', Proceedings of the Royal Society: Biological Sciences 281: 20140518 - pdf - in colonies from habitats across a large geographic range (Western US), field foraging distance correlates negatively with lab aggression, number of foragers, and threat response: these thus form a syndrome (independent of colony size, no of queens, or no of brood) - with more risk-tolerant (fewer, further foragers, more aggressive) colonies at higher latitudes; activity level in the colony without threat does not correlate.

Bengston SE, Dornhaus A 2015 ‘Latitudinal variation in behaviors linked to risk-tolerance is driven by nest-site competition and spatial distribution in the ant Temnothorax rugatulus’, Behavioral Ecology and Sociobiology 69: 1265-1274 - pdf - of a large number of environmental variables (related to competition, predation, resource avail-ability, or environmental stress), nest-site competition best predicts colony behavior (more competition ~ more risk tolerant)

Bengston S, Shin M, Dornhaus A 2017 ‘Life-history strategy and behavioral type: Risk-tolerance reflects growth rate and energy allocation in ant colonies’, Oikos 126: 556-564 - pdf - more risk-tolerant colonies invest more in reproduction (queens/males) and less in growth (new workers)