Student Theses and Dissertations
Date of Award
2025
Document Type
Thesis
Degree Name
Doctor of Philosophy (PhD)
Thesis Advisor
Daniel Kronauer
Keywords
nest relocation, army ants, clonal raider ants, Ooceraea biroi, phasic lifecycle, collective behavior
Abstract
Nest relocation is integral to the lives of many social insects. Army ants have taken this behavior to the extreme, with many species relocating an entire colony of over 100,000 ants plus brood almost daily. Despite its prevalence, the question of how army ant colonies emigrate has been debated for many decades, and still awaits a definitive answer because conducting well-controlled field experiments with their massive and aggressive colonies is challenging. In ants, the Dorylinae subfamily has given rise to most known army ants. Therefore, performing experiments in non-army ant dorylines that can be maintained in a laboratory setting presents an attractive and viable solution. The clonal raider ant, Ooceraea biroi, is a non-army ant doryline that exhibits army ant-like characteristics. Though nearly impossible to study in the field due to their subterranean lifestyle, their queenless, asexually reproducing colonies render them an ideal model to investigate doryline biology in the lab. Taking advantage of the benefits of O. biroi as a model, I developed an assay in which I could study the dynamics of their never-before-seen nest relocation habits with unprecedented experimental control. In this thesis I present two projects which aimed to 1) discern how nomadism fits into O. biroi's life history, and 2) uncover the sociobehavioral mechanisms that facilitate their emigrations. O. biroi exhibits a phasic colony lifecycle consisting of two stereotyped phases that occur in alternation: the reproductive phase, where the adults remain inside the nest while their eggs and pupae develop, and the brood care phase, where old ants leave the nest to forage and the young ants tend to the larvae at home. In the first experiment, colonies were videorecorded over 1.5 reproductive cycles and had free access to four distinct nest sites. I found that colonies relocated their nest frequently and under phasic control, emigrating only during the brood care phase, when larvae were present in the third and fourth instars. This phasic nomadism exactly parallels what is known from phasic army ants. In my second experiment, I used individually tagged ants and automated behavioral tracking to follow colonies as they emigrated between two nest sites. I found that emigrations could be divided into three qualitative phases: the scouting phase, the relocation phase, and the settling phase. Division of labor was found to be mediated by age and by personal information. Age-related differences in movement patterns underscored the spatiotemporal dynamics of relocating colonies: old ants predominately explored the foraging arena during the scouting phase, and young ants relocated into the target site more quickly than old ants during the relocation phase. Personal information dominated task allocation: recruitment of nestmates was performed by ants that had recently visited the target site. Both age groups participated equally in the task of brood transport. This body of work is foundational to the investigation of doryline and army ant emigration in the lab and has implications for the evolution of army ant-like behavior. It also establishes a novel behavioral system for research in collective behavior and distributed decision-making. Altogether, I expand our knowledge of the clonal raider ant's behavioral repertoire and further its claim as a promising model organism for future research and scientific advancement.
License and Reuse Information
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Recommended Citation
Melendez, Dennis Octavio, "The Spatiotemporal Dynamics of Nomadic Behavior in the Clonal Raider Ant, Ooceraea Biroi" (2025). Student Theses and Dissertations. 817.
https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/817
Comments
A Thesis Presented to the Faculty of The Rockefeller University in Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy