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.
