Researchers have identified that a chemical compound, isopropyl myristate (IPM), acts as a pheromone in naked mole-rat colonies to suppress reproduction and aggression among non-breeding members. Published in Nature, the study confirms that this scent helps the queen maintain social stability and control within her colony.
The Role of Isopropyl Myristate in Colony Stability
Deep beneath the ground, naked mole-rat queens maintain strict social hierarchies. New findings from the Max Delbrück Center for Molecular Medicine indicate that this authority is not maintained through physical dominance alone. Instead, the queen broadcasts a chemical signal, identified as isopropyl myristate (IPM), which is present at significantly higher concentrations in queens than in subordinate colony members.
The research suggests that IPM serves as a mammalian version of a queen pheromone
similar to those found in eusocial insects like ants and bees. By detecting this scent, subordinate females experience physiological changes that keep them in a non-reproductive state.
Hormonal Suppression and Behavioral Control
The study provides a clear mechanism for how this chemical communication influences the colony’s biology. When exposed to the queen’s scent, subordinate naked mole-rats show elevated levels of prolactin, a hormone that suppresses fertility. Simultaneously, progesterone levels and general reproductive activation decrease.
Beyond hormonal regulation, the compound acts as a behavioral sedative. Researchers demonstrated this by removing the queen from captive colonies, which typically results in intense, often lethal, aggression as other females vie for the vacant leadership role. When the team applied synthetic IPM to the colony’s bedding, the aggressive behavior was suppressed, keeping the colony stable for 12 weeks.
Research Methodology and Ethical Oversight
The findings are the result of multi-year, multi-institutional efforts across several countries. Laboratory colonies were maintained under strict environmental controls in Berlin, Germany, and Pretoria, South Africa. According to Nature, researchers used custom-designed, interconnected chamber systems to house the animals and employed non-invasive salivary swabs to genotype the animals for sex determination using the Sry gene.
All procedures were conducted under rigorous ethical standards, with approval from the University of Pretoria and local governmental authorities in Berlin, including the Landesamt für Gesundheit und Soziales.
Limitations and Future Scientific Inquiry
Despite the success of the IPM application in controlled environments, the researchers caution that this chemical signal is likely only one component of a broader communication system. Other factors, such as vocalizations and complex social interactions, remain critical to colony organization.
Furthermore, it remains unclear whether this chemical mechanism functions identically in wild populations. As noted in the reporting, the researchers emphasize that further study is required to determine how these chemical cues operate outside of laboratory settings. When the synthetic treatment was removed in the experimental trials, the colony’s fragile peace immediately dissolved, resulting in renewed aggression and the eventual establishment of a new queen through lethal conflict.