Author ORCID Identifier


Date of Award

Fall 11-2-2022

Document Type

Thesis (Ph.D.)

Department or Program

Ecology, Evolution, Environment and Society

First Advisor

Mark Laidre

Second Advisor

Matt Ayres

Third Advisor

Carey Nadell


Sociality is a strategy many animals employ to cope with their environments, enabling them to survive and reproduce more successfully than would otherwise be possible. When navigating their environments and making decisions, social individuals often use information provided by conspecifics (in the form of social cues and signals), thereby increasing the scope and reliability of the information they can gather. However, social information use may be influenced by many factors, including key differences in context across the physical and social environment. My thesis asks and answers a series of questions regarding the trade-offs in social information use across different contexts, with particular focus on signals (chapters 1 and 2) and movement (chapters 3 and 4). Using experimental manipulations of the highly social terrestrial hermit crab (Coenobita compressus) and the less social marine hermit crab (Pagurus bernhardus) I explored social information use across four key areas of behaviour critical to the success of most social organisms: (1) communication, (2) signal evolution, (3) movement, and (4) information transmission. For (1) communication, I tested the production of and response to threat displays across species, examining the evolutionary loss of these displays in species from dramatically different physical and social environments. For (2) signal evolution, I tested the correlation between red colouration and resource holding potential (RHP) across body parts with different signalling potential, based on whether they are exposed or covered by surrounding shell architecture. For (3) movement, I tested whether individuals were biased in their movement by their social group, and whether the level of movement bias changed in different contexts, with individuals having their own private source of protection—a shell—that supersedes the group. Finally, for (4) information transmission, I tested the capacity for information gathering via antennal contact, experimentally seeding social information in the wild to examine whether social information is beneficial to receive and costly to bear. Ultimately, by synthesising social information use across these four important contexts, I have addressed key questions about how and why social context modifies behaviour, and the ways in which a highly valuable and limiting resource—architecturally remodelled shells—shape social behaviours.

Original Citation

Chapter 1:

Doherty C.T.M. and M.E. Laidre. 2020. Evolutionary loss of threat display in more social species: phylogenetic comparisons, natural interactions in the wild, and experiments with models. Behaviour. 157:1025-1058. doi:10.1163/1568539X-bja10038.

Chapter 3:

Doherty C.T.M. and M.E Laidre. 2022. Individualism vs collective movement during travel. Scientific Reports. doi:10.1038/s41598-022-11469-1