More than pheromones: How ants combine signals to commun

Ant communication has long been viewed as dominated by chemical signals, yet growing evidence suggests a more complex picture. In their Focus contribution, “Multimodal communication in ants (Hymenoptera: Formicidae): the interplay of chemical and vibro-acoustic signals,” Ciaralli and colleagues synthesize research showing how ant colonies combine pheromones with substrate-borne vibrations. By compiling these communication modes across species and behavioural contexts, the authors highlight how multimodality has shaped information transfer in ant societies.

Edit by Purbayan Ghosh and Salvatore Brunetti

Interview with Simone Ciaralli

MNB: Could you tell us a bit about yourself?

SC: I’m currently a PhD student at the University of Turin (Italy) working in the Vibrant Lab, a research group focused on insect communication and interactions. I grew up in a small village in central Italy, surrounded by nature, which sparked my fascination with animals and their interactions. This early connection led me to earn a bachelor’s degree in Natural Sciences, followed by a Master’s in Animal Behaviour. Throughout my academic journey, I’ve worked on various research projects exploring animal behaviour and communication across different species, from frogs and birds to my current PhD work on ants and other insects. In short, I love watching animals and asking questions about how they interact with each other and their environment, trying to grasp something more about the complex natural systems that shape our world.

MNB: Could you briefly outline your research on “Multimodal communication in ants (Hymenoptera: Formicidae): the interplay of chemical and vibro-acoustic signals” in layperson’s terms?

SC: Multimodal communication refers to the simultaneous use of signals from different sensory modalities, such as when an ant releases pheromones while stridulating. This combination can enhance communication by allowing receivers to integrate multiple cues and respond differently than they would to single signals. However, research on multimodal communication in ants has so far been scattered across different studies. We aimed to bring this knowledge together by combining past reviews with recent findings, identifying solid experimental evidence and outlining new hypotheses. The result is an overview of multimodal communication in ants, including which species use it, what it is used for, and how such complex signalling may have evolved in ant societies.

MNB: What is the take-home message of your work?

SC: Communication in complex social systems such as ant colonies is often more sophisticated than we might expect. A growing body of evidence shows that ants widely use multimodal signals, combining different types of cues to communicate. These signals play a key role in recruitment and alarm communication, allowing colonies to finely tune social responses. Multimodal communication may have evolved as an adaptation to complex environments, such as forests, where relying on a single chemical or acoustic signal can be limiting due to obstacles that interfere with signal transmission. Multimodality also appears to have evolved independently in different ant lineages, and there is still much to learn about how these communication systems evolved within ant social networks.

MNB: What was your motivation for this study?

SC: Along with my PhD supervisors, Prof. Luca Casacci and Prof. Francesca Barbero, I became interested in the study of multimodal communication in complex social systems. While this was a very active research area in the 1990s and early 2000s, much of the literature consists of reviews rather than direct experimental evidence. We wanted to take a step back and ask what we really know, by identifying the ant groups in which multimodal communication has been clearly demonstrated. This approach allowed us to better explore how multimodal communication may have evolved in social insects.

MNB: What was the biggest obstacle you had to overcome in this project?

SC: One of the main obstacles was finding old studies and then integrating results from many different papers into a single, coherent framework. Making sense of findings collected years apart, while staying as objective and true to the original work as possible, can be challenging. At the same time, it was a really stimulating process, stressful at moments but also a lot of fun.

MNB: Do you have any tips for others who are interested in doing related research?

SC: Curiosity, patience, and perseverance are key. Working with social insects can be demanding, and even accessing information can feel stressful, but that’s part of doing science. When it comes to literature reviews, following standard protocols such as PRISMA can be extremely helpful for organising and standardising your work. For experiments, whether in the field or the lab, curiosity is essential: have fun, ask plenty of questions, and don’t give up, because something unexpected often emerges. Finally, please publish everything, even negative results. Although it can be difficult in today’s publishing landscape, negative findings are crucial for scientific progress. A couple of negative results from experiments that were performed but never published could have helped me a lot in my literature review, and in the planning of my PhD project.

MNB: Where do you see the future for this particular field of ant research?

SC: I think there is still a great deal to be explored when it comes to multimodal communication in ants. This includes basic questions, such as which species use multimodal signals and which do not, as well as more detailed investigations into the behavioural roles of these signals, which have rarely been tested experimentally. I expect many exciting discoveries ahead, particularly in understanding how ants exchange information so efficiently within their large social networks and the evolutionary pathways that have led to the complex signals we observe today.