Author Type

Graduate Student

Date of Award

1979

Document Type

Thesis

Publication Status

Version of Record

Submission Date

October 2026

Thesis/Dissertation Advisor [Chair]

Courtenay, Walter R. Jr.

Abstract

Two gynogenetically reproducing unisexuals, the diploid Poecilia formosa and its associated triploid are sympatric to P. mexicana, a bisexual species, in northeastern Mexico. All compete for sperm from P. mexicana males. Field and laboratory experiments studied habitat. preferences and associations as mechanisms of reducing competition. A new tagging method was developed. Laboratory results (Phase One) indicated habitat preferences of each female type. Further studies (Phase Two) showed the fishes remained together but each female type associated with its own kind. Shade and a gravel substrate were important habitat parameters. Specific habitat preferences may not be adaptive due to seasonal water fluctuations but there are different ecological preferences by each female type. Associations could account for Phase One laboratory results and ecological differences. Combined data indicate associations are the likely mechanism, but habitat preferences are possible. Seasonal factors and artificial conditions may have caused diverse results.

Extent

88 p.

Comments

Charles E. Schmidt College of Science|Thesis (M.S.)--Florida Atlantic University, 1979.|FAU Electronic Theses and Dissertations Collection|Charles E. Schmidt College of Science

Identifier

FADT13960

Format

pdf

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