Antennal Sensilla Basiconica Responses to Pheromones and General Odorants in Red Imported Fire Ants, Solenopsis invicta

Authors: Du, Yuzhe; Chen, Jian

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2026
Publication Date: 1/23/2026
Citation: Du, Y., Chen, J. 2026. Antennal Sensilla Basiconica Responses to Pheromones and General Odorants in Red Imported Fire Ants, Solenopsis invicta. Insects. 17(2):129. https://doi.org/10.3390/insects17020129.
DOI: https://doi.org/10.3390/insects17020129

Interpretive Summary: The red imported fire ant (Solenopsis invicta) is one of the most damaging invasive pests in the United States. These ants form massive colonies, attack crops, harm wildlife, and even pose risks to human health. Their success as invaders depends heavily on their ability to communicate through chemical signals, which help them organize their colonies and respond to threats. Understanding how fire ants detect and respond to these chemical cues is essential for finding better ways to control them. In this study, we investigated how fire ants use their sense of smell by recording the activity of tiny sensory organs on their antennae called sensilla basiconica. These organs contain nerve cells that detect chemical signals. Researchers tested 62 different chemicals—including pheromones, plant odors, and essential oils—on both worker ants and female alates (winged ants that start new colonies). They discovered that these sensory organs respond strongly to many different odors, but workers and female alates detect some chemicals differently. Workers were more sensitive to nine compounds, while female alates were more sensitive to six.This study provides the first detailed map of how fire ants smell and respond to odors. By showing that workers and female alates have different sensitivities, it reveals how their roles in the colony are supported by their sense of smell. These insights into fire ant chemical communication could help scientists design new, more effective strategies to disrupt their behavior—such as lures, repellents, or targeted control methods—ultimately reducing the damage fire ants cause to agriculture, ecosystems, and communities.

Technical Abstract: The red imported fire ant, Solenopsis invicta Buren, is a eusocial insect that relies on a complex chemical communication system for colony’s integrity and maintenance. Their olfactory system plays a critical role in detecting semiochemicals in the environment. In this study, we conducted single sensillum recording (SSR) to examine the olfactory neuronal responses of female alates and workers specific to olfactory sensilla basiconica to a panel of sixty-two individual pheromones and general odorants, including terpene, terpenoids, pyrazine, pyridine, ketone, aldehyde, alcohol, acid, aliphatic and aromatic acetate, benzoate, benzyl ester, and three essential oils. The results showed that the basiconica sensilla, which contain multiple olfactory receptor neurons (ORNs), displayed moderate to strong responses to most of the tested compounds, with a broad spectrum of sensitivity to all tested pheromones and general odorants. The electrophysiological analysis also revealed differences in sensory detection between S. invicta workers and female alates. Comparing olfactory responses to the same panel of odorant stimuli, the multiple ORNs within sensilla basiconica elicited the similar responses to forty-seven compounds, while sensilla basiconica of workers displayed greater responses to nine compounds, and female alate exhibited greater responses to six compounds. The differences between workers and female alates indicate their distinct roles in ant colony. This study furnishes the first comprehensive map of the olfactory responses of sensilla basiconica, to general odorants in S. invicta female alates and workers, which will facilitate our understanding in chemical ecology of S, invicta and may have implication for the development of more effective methods for managing fire ants.