Graduation Date

Spring 2026

Document Type

Thesis

Program

Master of Science degree with a major in Biology

Committee Chair Name

Allison Bronson Ph.D.

Committee Chair Affiliation

Cal Poly Humboldt Faculty or Staff

Second Committee Member Name

John Reiss Ph.D.

Second Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Third Committee Member Name

Karen Kiemnec-Tyburczy Ph.D.

Third Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Fourth Committee Member Name

Jose Marin Jarrin Ph.D.

Fourth Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Keywords

Morphology, Evolution, Anatomy, Kidneys, Stickleback, Gasterosteales, Tubesnout, Histology, In situ hybridization, CT scanning

Subject Categories

Biology

Abstract

Aulorhynchus flavidus (Gasterosteidae, Gasterosteales) is a common schooling fish that inhabits nearshore habitats on the Pacific Coast of North America. Breeding male Aulorhynchus have been observed excreting a glue-like substance from their vents to create nests in macroalgae (Macrocystis, Nereocystis, and Zostera); Aulorhynchus is the only non-stickleback within the Gasterosteales known to exhibit this trait. Glue production also occurs in all stickleback members of the Gasterosteales, and the genomic and morphological source of the glue, as well as the amino acid structures of the substance itself, has been characterized. In Aulorhynchus, the substance is hypothesized to be produced from homologous structures and genes, but this has not yet been confirmed. Thus, the objective of this study was to use a combination of gross dissection, histology, in situ hybridization, peptide fingerprinting, and computed tomography to characterize glue production in Aulorhynchus. Histology showed that the renal morphology of breeding male Aulorhynchus includes greatly hypertrophied kidneys and kidney tubules, similar to the condition found in breeding male sticklebacks. Additionally, proteins in Aulorhynchus glue were found to be similar to stickleback glue proteins; glue production genes from sticklebacks are also expressed in the kidneys of breeding males, suggesting homology of these genetic and anatomical mechanisms. Ancestral state reconstructions using recent topologies of the Gasterosteales were also performed to place the clade’s glue production trait in a phylogenetic context, which may indicate that glue production arose in the common ancestor of the Gasterosteales. These findings add to the limited morphological and life history data available for A. flavidus, highlighting the importance of basic biology studies of abundant forage fish.

Citation Style

Copeia

Available for download on Sunday, May 11, 2031

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