Diet of the Mudpuppy (Necturus maculosus) in Eastern Kansas

Abstract

The Mudpuppy (Necturus maculosus) is a rarely seen and poorly understood permanently aquatic salamander of the eastern United States. Little has been published on its habits within extensive portions of its range, especially within the Missouri and Arkansas river drainages, where better knowledge of its natural history is needed to assess its status and inform conservation efforts. I investigated trophic relationships of the Mudpuppy in those drainages by examining its diet using samples from 195 individuals captured in the Marais des Cygnes, Neosho, Cottonwood, Elk, and Verdigris rivers and at Melvern and Pomona lakes, all in Kansas. I extracted the stomach contents of each individual with a non-lethal flushing protocol to describe dietary differences in abundance, frequency of occurrence, volume, and taxonomic diversity of prey items according to habitat, season, Mudpuppy sex, and Mudpuppy size. I estimated the trophic position of the Mudpuppy based on identities, volumes, and trophic levels of its prey, and found it to be a top-level predator with a wide-breadth foraging niche in both rivers and lakes. Individuals fed intensively on insects—the largest number of prey items were mayfly nymphs (Ephemeroptera)—but volumetrically their diets were mainly fishes, especially sunfishes (Lepomis spp.) and Gizzard Shad (Dorosoma cepedianum). Fishes were recovered from the great majority of individuals, and insects from most, whereas frequencies of occurrence of other prey types were considerably lower. Mudpuppies from rivers, as compared to lakes, consumed a significantly larger number but not volume of fishes and, in both respects, more

amphibians. No significant differences in diets between seasons (winter versus spring) or sexes were detected. Mudpuppy size was weakly correlated with total prey volume and with volume of fishes in particular. Altogether, these findings differ markedly from previous studies conducted elsewhere, underscoring the need for more studies from throughout the Mudpuppy’s range.