Chromogenic behaviors and mechanisms of chromatophore control in squid
Abstract/Contents
- Abstract
- Cephalopod chromatophores are small organs that provide the means for much of the elaborate color changing behaviors frequently observed in squid, octopus, and cuttlefish. The vast majority of what is currently known about the anatomy, physiology, and use of chromatophores in squid derives from studies conducted on species of squid from the primarily shallow water dwelling family Loliginidae. This thesis examines the natural chromogenic behaviors and the anatomy and physiology of the chromatophore layer in the ommastrephid squid, Dosidicus gigas, and compares the findings to the chromatophores of the loliginid squid Doryteuthis opalescens. Video of free-swimming Dosidicus from the animal-borne video package Crittercam revealed two novel dynamic displays that differ greatly from the primarily static displays previously documented in loliginid squids. The "flashing" display in Dosidicus is characterized by a rapid oscillation of body coloration from red to white, and is likely a form of intraspecific communication. "Flickering" on the other hand consists of oscillating waves of chromatophore activity that propagate across the skin and is likely a form of dynamic camouflage. These differences in chromatophore use compared to loliginid squids are reflected in the anatomy and physiology of the chromatophore layer in Dosidicus. As in loliginid squids, L-glutamate (L-Glu) and serotonin (5-HT) are both endogenous neurotransmitters to the chromatophore system with excitatory and inhibitory effects respectively. However, the chromatophores of Dosidicus are much more sparsely innervated compared to what has been documented in loliginid squids. Furthermore, spontaneous waves of chromatophore activity are frequently observed in excised skin samples of recently dead Dosidicus. Similar waves can only be elicited in D. opalescens after 5-7 days of chronic denervation of the chromatophore layer, a process that results in almost total degradation of both glutamatergic and serotonergic axons in the chromatophore layer in D. opalescens. In both species, spontaneous wave were resistant to the inhibitory effects of the potent neurotoxin tetrodotoxin (TTX) at concentrations that abolished electrically stimulated chromatophore activity, indicating a separate control mechanism. The waves were sensitive to the inhibitory effects of 5-HT. These results indicate one role of 5-HT in the chromatophore system of both the ommastrephid squid Dosidicus and in loliginid squids may be to regulate spontaneous waves of chromatophore activity without interfering with the excitatory innervation of the chromatophores to different degrees depending on chromatophore use in each species.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Rosen, Hannah Elizabeth |
|---|---|
| Associated with | Stanford University, Department of Biology. |
| Primary advisor | Gilly, William |
| Thesis advisor | Gilly, William |
| Thesis advisor | Lowe, Christopher, (Associate professor of biology) |
| Thesis advisor | Thompson, Stuart |
| Advisor | Lowe, Christopher, (Associate professor of biology) |
| Advisor | Thompson, Stuart |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Hannah Elizabeth Rosen. |
|---|---|
| Note | Submitted to the Department of Biology. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Hannah Rosen
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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