Brood care gene steers the division of labor among ants

Researchers identify a gene whose activity regulates the sensitivity to brood scent and thus influences the brood care behavior of ants

JOINT PRESS RELEASE OF THE SENCKENBERG BIODIVERSITY AND CLIMATE RESEARCH CENTRE AND JOHANNES GUTENBERG UNIVERSITY MAINZ

19 June 2018

The success of ant colonies is based on a strict division of labor. However, until now the genes responsible for regulating the behavior of the workers have not been known. Now scientists at Johannes Gutenberg University Mainz (JGU) 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 behavior 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.

In ant colonies, there is a strict division of labor. 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 Johannes Gutenberg University Mainz and at 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 (Vg) 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," explained Professor Susanne Foitzik of the Institute of Organismic and Molecular Evolution at Mainz University.

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 labor 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 is based on group members specializing in certain tasks, who carry out these tasks more efficiently. To date, however, little is known about the mechanisms that lead to the specialization of the workers.

"To date, only in honey bees a gene has been identified which regulates foraging behavior. Our first record of a gene in ants that regulates brood care, which is another important task, has therefore closed a knowledge gap in the genetically-based behavioral control of social insects," summarized Dr. Barbara Feldmeyer of the Senckenberg Biodiversity and Climate Research Centre.