Phylogenetic Systematics of Snubnose Darters (Percidae, Etheostoma), With Discussion of Reproductive Behavior, Sexual Selection, and the Evolution of Male Breeding Color

154 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998.Snubnose darters are a speciose group of fishes in the family Percidae (North American darters and Holarctic perches and walleye). In the past 20 years, many new species have been described and much work has been done on the behavior of these fishes. However, phylogenetic relationships both among snubnose darter species and between snubnose darters and close relatives have not been clearly resolved. This dissertation used an original data set, complete cytochrome b DNA sequences, to address the molecular systematics of snubnose darters. The resulting phylogeny was compared with previously published hypotheses, as well as hypotheses obtained from reanalysis of previously published morphological data sets. Information on snubnose darter spawning behavior was collected from snorkeling and filming in natural environments, and corroborated previous descriptions of behavior from aquarium observations. Spawning behavior, including substrate searching, lateral quivers and head jabs, was similar in the two environments, although spawns were significantly longer for pairs spawning in aquaria than for pairs spawning in the field. Egg deposition behavior was similar in streams and aquaria, differing only in the occasional use of substrates not available in natural environments (e.g., fine gravel or aquarium hardware) as egg attachment sites in some aquarium-held species. Results of sexual selection experiments (mate choice and male interaction) conducted in aquaria suggested that snubnose darter males compete for access to females using fin displays and aggression. The role of female choice of bright colors in males remained unclear due to low sample sizes. Other aspects of sexual selection in snubnose darters were discussed, including a trend towards choice of larger mates in both males and females as well as reproductive strategies. Finally, a data set of male breeding color characters was coded for the snubnose darters and putative close relatives and mapped on the cytochrome b topology to study their evolution as well as to propose speciation hypotheses implicating sexual selection as a force in the snubnose darter radiation.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD