The researchers have revealed that the neuropeptide inotocin controls the synthesis of hydrocarbons on the body surface of ants and contributes to enhancing the resistance of worker ants to dry environments, in collaboration with the University of Tokyo and the University of Lausanne.

Recent research on humans, primates, and rodents has shown that peptide hormones called oxytocin or vasopressin are involved with control of social behavior such as attachment, parenting, and aggression. These oxytocin/vasopressin family-peptides are highly conserved in fish, birds, and even insects. Elucidation of the physiological roles of these family-peptides and particularly the relation to social behavior is important for clarifying the control mechanisms and evolution of social behavior in living organisms. However, it is still unclear how these peptides control social behavior in non-mammalian organisms.

Ants are social insects and live in groups with a complex sociality. Worker ants in particular account for the vast majority of the group, with younger ants in charge of parenting inside the nest and older ants in charge of foraging and patrolling outside the nest. Older ants working outside the nest experience changes in outdoor temperature and humidity, and they must be active while enduring the dry environment of the ground surface. The researchers have examined the expression levels of inotocin between young workers staying the nest and old workers active outside. In addition, they used the gene knockdown method or pharmacological treatment to manipulate inotocin signaling. It was clarified that inotocin controls the synthesis of hydrocarbons that prevent the water loss from the body surface, and also plays a part in the physiological adaptation that supports the social division of labor of worker ants.

In ant research, the researchers intend to further investigate the detailed relationship between sociality and genes by focusing in particular on the relation of inotocin functions to social behavior.