Author ORCID Identifier

Date of Award

Fall 11-4-2022

Document Type

Thesis (Ph.D.)

Department or Program

Ecology, Evolution, Environment and Society

First Advisor

Mark E. Laidre


Social animals, and even solitary animals, must at different points in their life actively search for and locate conspecifics within their environment, using one or multiple senses. One sense in particular, vision, can provide some of the most spatially detailed and temporally rapid information about the environment. Yet, the surrounding environment can also severely challenge animals’ abilities to find fellow conspecifics. Furthermore, once an animal successfully locates conspecifics, it must then make key decisions about when and where to enter group formations, decisions which may strongly impact their access to socially-acquired resources. Even after an animal has positioned itself within a group, it may still rely on vision to successfully interact with conspecifics and acquire the benefits of sociality. My thesis addresses the question of how and why animal visual systems are shaped by both the physical and the social world, as animals attempt to find (chapter 1), enter (chapter 2), and interact (chapter 3) with social formations. In addition, I address how and why the morphology of the eye itself may be linked to specific features of the physical and social environment (chapter 4). Chapters 1-3 focus on field-based behavioral experiments of the highly social terrestrial hermit crab (Coenobita compressus). Chapter 4 compares multiple species within the clade of hermit crabs, which span a range of environments. In chapter 1, we tested how the environment can place sensory constraints on an animal’s ability to locate a social group. In chapter 2, we tested how different elements of a social group’s orientation and organization impact an outsider’s ability to detect and position itself within the group. In chapter 3, we tested how the experimentally-induced loss of vision can impact individuals’ social behavior. Finally, in chapter 4, we compared macroscopic and microscopic dimensions of eye morphology across three species of hermit crab, which inhabit different environments. Overall, my thesis disentangles the complex relationship between an animal’s sensory system and the physical and social environment, revealing the overriding importance of vision in locating conspecifics, entering groups, and making social decisions in complex environments.