Tests of Adaptive Coloration Hypotheses for Madtom (Notorus) Catfishes (Siluriformes: Ictaluridae)

Predators select for defensive adaptations, such as stings, toxins, and camouflage color patterns. Madtoms, Noturus, are diminutive catfishes with dorsal and pectoral stings. Thirteen of the 25 nominal species have serrated spines in the pectoral sting and a contrasting pigment pattern. Behavior of two saddled species, N. miurus and N. hildebrandi, and one uniformly colored species, N. leptacanthus, was investigated to test if the pigment pattern is camouflage. Saddle spacing and crypticity of the saddled species were measured against various substrates and were found to be unevenly spaced, which could be camouflage when viewed against gravel. Given substrate choices, madtoms preferred gravel during daylight conditions. In subsequent experiments, all species were given colored gravel to test color vs. texture-based substrate choice and preferred dark substrates. In the presence of a predator stimulus, madtoms preferred gravel at night and dawn. The pigment pattern likely is camouflage when viewed against gravel substrates.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biological Sciences

Year

2003

Author dc:creator

• Stokes, Amanda

Contributors dc:contributor

• Grady, James
• Cashner, Robert
• Johnson, Steve

• Predator Avoidance
• Madtoms
• Color Patterns
• Defense adaptations

Repository record dc:identifier

https://scholarworks.uno.edu/td/57

OAI identifier oai:identifier

oai:scholarworks.uno.edu:td-1056