Seasonal Diet of the Margined Madtom, 
Noturus insignis (Osteichthyes: Ictaluridae), 
in a North Carolina Piedmont Stream 
Robert P. Creed, Jr., 1 and Seth R. Reice 
Department of Biology, Coker Hall 010- A 
University of North Carolina 
Chapel Hill, North Carolina 27514 
ABSTRACT . — The diet of four size classes of the margined madtom, 
Noturus insignis, collected during 1 year from New Hope Creek, 
Orange Co., N.C., was examined. Margined madtoms consumed a 
wide variety of prey, but most (93.8%) were Diptera, Ephemeroptera, 
Trichoptera, and Plecoptera. On average, fewer individual prey were 
consumed during the winter than in any of the other three seasons. 
Many prey species were most abundant in the madtom’s diet when 
those prey appeared to be most abundant in the stream. The diversity 
of the madtom’s diet increased as the fish increased in size. Small 
madtoms consumed primarily chironomid larvae ( >70% of the diet). 
Although chironomids were still a major prey item numerically for 
large madtoms, 65-70% of their diet consisted of other taxa. We 
hypothesize that the diet of the madtom diversifies with increasing size 
because large madtoms are able to capture large prey successfully and 
are able to forage in areas with high current velocities. 
The margined madtom, Noturus insignis (Richardson), is a common 
benthic fish in streams of eastern North America from New York to 
Georgia (Rohde 1980). Despite the margined madtom’s widespread 
distribution, characterization of its diet is based on only three individuals 
collected by Flemer and Woolcott (1966) between 13 June and 22 
December, 1958. Flemer and Woolcott found a dipteran larva, two 
stoneflies, and unidentified insect and fish remains in the stomachs of 
the margined madtoms they sampled. The present study had two major 
goals. First, we wanted to provide more detailed information about the 
diet of N. insignis in the southern part of the species range. Second, we 
wanted to determine if the diet of margined madtoms changed with 
either the season or the size of the fish. 
METHODS 
Margined madtoms wdre sampled from a series of three riffles and 
three pools (about 150 m of stream) in New Hope Creek, a fourth-order 
Present address: W. K. Kellogg Biological Station, Department of Zoology, Michigan 
State University, Hickory Corners, MI 49060. 
Brimleyana 16:23-32, July 1990 
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