Author ORCID Identifier
0009-0003-5871-8306
Biosketch
Dr. Sree Subha Ramaswamy is a behavioural biologist whose doctoral research focused on collective construction and chemical communication in mound-building termites. She completed her PhD at the National Centre for Biological Sciences (NCBS), Tata Institute of Fundamental Research, Bengaluru, India. Her research investigated how social insects coordinate large-scale architectural construction without centralized control.
Using Odontotermes obesus as a model system, she examined how different worker castes respond to volatile and non-volatile soil-borne chemical cues during mound repair and building. Her work combined behavioural assays, controlled environmental manipulations, and quantitative analysis to explore caste-specific sensitivity to construction signals. Through these experiments, she contributed to a deeper understanding of stigmergy, distributed coordination, and the sensory mechanisms underlying collective behaviour. Beyond termite construction, her broader interests include animal cognition, sensory ecology, and how organisms interpret complex natural environments through limited sensory systems.
Her work integrates behavioural experiments with ecological and mechanistic perspectives to uncover how simple individual rules give rise to sophisticated group-level patterns. Following her doctoral research, she transitioned into applied behavioural science, working at the intersection of animal cognition and translational research. She continues to be interested in how biological systems process information, make decisions, and generate emergent structure.
Date of Award
11-8-2025
Document Type
Thesis
School
School of Chemical & Biotechnology
Programme
Ph.D.-Doctoral of Philosophy
Second Advisor
Prof. Sanjay P. Sane
Keywords
Animal Behavior, Collective Behavior, Social Insects, Chemical Communication, Neuroethology
Abstract
Nest-building in social insects requires layered communication to coordinate complex, functional structures for housing, protection, storage, and homeostasis. This is especially striking in mound-building termites, which construct and repair large mounds collectively despite lacking image-forming eyes. This thesis investigates how Odontotermes obesus achieves such coordination through chemical communication embedded in soil.
Using controlled two-choice assays with manipulated soils, I separated airborne volatile signals from contact non-volatile signals by baking to remove volatiles, a mesh assay that presented volatile cues without contact, and solvent extraction with reapplication of contact cues. I quantified responses in major-only, minor-only, and mixed groups at two densities. Termites distinguished unprocessed from termite-processed soil and preferred the latter. This preference was mediated by both short-lived volatile compounds and persistent non-volatile signals. Caste responses diverged when evaluating colony soil.
Minor workers required co-localised volatile and non-volatile cues to show strong attraction, whereas major workers responded to long-lived non-volatile cues even without volatiles. The cues also carried colony-specific information, enabling discrimination between home and foreign mound soils. To explain how mixed-caste groups reach consensus despite divergent preferences, I evaluated three coordination hypotheses: averaging of caste preferences, cue dominance in which one cue class governs the decision, and emergent collective responses.
Group behaviour varied with density and with cue context, indicating dynamic recruitment and context-dependent modulation rather than simple summation of individual actions. I outline a working three-phase model of collective building that includes initiation, amplification, and termination, integrating caste roles, environmental cues, and feedback. Together, these results show how decentralised termite societies coordinate construction through layered, caste-specific chemical communication.
Recommended Citation
Ramaswamy, Sree Subha Ms, "Chemically Mediated Communication In Mound-Building Termites" (2025). Theses and Dissertations. 187.
https://knowledgeconnect.sastra.edu/theses/187