The success of ant colonies is based on a strict division of labour. However, until now the genes responsible for regulating the behaviour of the workers have not been known. Now scientists at the University of Mainz and the Senckenberg Biodiversity and Climate Research Centre have identified a gene, whose activity regulates the sensitivity to brood scent and thus influences the brood care behaviour of ants. This is the result of genetic studies and experiments on the North American ant species Temnothorax longispinosus, as the group reports in the current issue of the journal “PLoS Biology”.
A strict division of labour prevails in the ant colony. The queen is primarily responsible for reproduction. The workers carry out all other tasks, which change significantly over the course of their lives. Young worker ants take care of the young and engage in brood care. Middle-aged workers take care of their adult nestmates. Towards the end of their lives, they go foraging for food.
Scientists at the University of Mainz and the Senckenberg Biodiversity and Climate Research Centre have identified a gene that plays a key role in these changing responsibilities. “In a gene expression study we discovered that the Vitellogenin gene like-A is more active in brood carers than among the workers who forage for food. This different gene activity influences the degree to which ants perceive task-related stimuli. Accordingly, the tasks they carry out change,” explains Professor Susanne Foitzik, Johannes Gutenberg University of Mainz.
Following the genetic study the group tested the role of the Vitellogenin gene like-A by means of an experiment. To this end, the gene was down-regulated in young workers of the North American species Temnothorax longispinosus. The ants thus manipulated cared for the brood to a lesser extent that ants of the same age in a control group. Instead they cared more for adult nestmates, a task they would normally assume later in life.
In line with theoretical models on the division of labour in social insects, this switch in tasks indicates that the ants are less sensitive to brood scents, and more sensitive to the signals of the adult workers.
Ants, like bees, wasps and termites, are social insects. The success of their communities based on group members specialising in certain tasks Thus they carry them out more efficiently. To date, however, little is known about the mechanisms that lead to the specialisation of the workers.
“To date, only in honey bees has a gene been identified, which regulates foraging behaviour. Our first record of a gene in ants that regulates brood care, i.e. another important task, has therefore closed a knowledge gap in the genetically-based behavioural control of social insects,” summarises Dr. Barbara Feldmeyer, Senckenberg Biodiversity and Climate Research Centre.
Kohlmeier, P., Feldmeyer, B. and Foitzik, S. (2018):Vitellogenin-like A–associated shifts in social cue responsiveness regulate behavioral task specialization in an ant. PLoS Biology 16(6): e2005747. doi: 10.1371/journal.pbio.2005747
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