How do Social Insects make Decisions?


Using information passed on by others can greatly improve individual fitness, and has been the fundamental mechanism underlying the evolution of social insects such as bees, wasps, ants and termites. However in some situations it is better to ignore social information and for an individual to use its own prior knowledge and experience. So how do these colony-forming insects tailor their reliance on social information for the benefit of the ‘superorganism’? Scientists have recently reviewed the literature and made theories as to the nature of decision making in insects.

Social information is relatively ‘cheap’ to obtain for hymenopteran foragers, because they can bypass the costs associated with exploration and food sources obtained socially are likely to be better quality. In the truly eusocial western honeybee, Apis mellifera, generations overlap so information passed on by the ‘waggle dance’ (movements conveying location and quality of food sources) increases the fitness of that colony. Foraging choice are further refined by chemical cues (pheromone trails) and simply presence of other foragers.

Relying on social information may also incur costs and may not lend an evolutionary advantage. In the case of the ant forager, if she ignores social information she may find a novel food source that will benefit the colony as a whole, whilst a well-used food source is depleted (I.e. exploration produces more up-to-date information). Honeybees that rely on dance information may take time to find a dancer and may need multiple viewing and excursions to find the communicated food source.

A trade-off between these advantages and disadvantages will adjust how often (and what proportion of) social insects rely on social information. All animals tend to display the most profitable information they know, so relying on social information may be more profitable than exploration. For example honeybees only communicate their dance after finding high quality food sources. ‘Social learning strategies’ in animals are genetically determined in response to environmental and social cues. One such approach is the ‘copy if dissatisfied’ strategy, where animals will use social information if their current information is below a fitness ‘threshold’. These optimum social learning strategies can also be acquired (ironically) through social learning.

Grüter, C., & Leadbeater, E. (2014). Insights from insects about adaptive social information use. Trends in ecology & evolution, 29(3), 177-184.


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