104 Ray E. Ashton, Jr. 



maculosus, but considerably different from the wide spectrum of aqua- 

 tic habitats used by northern Necturus. The two primary microhabitats 

 used by N. lewisi in Piedmont Plateau environments are broken meta- 

 morphic or granite rock over sandy-gravel bottoms, and along stream 

 banks where there are rock outcroppings. This is contrary to the find- 

 ings of Fedak (1971), who stated that leaf beds are of primary impor- 

 tance. We found that leaf beds are only occasionally visited, probably 

 on feeding forays. Use of burrows or rock outcroppings is primary and 

 similar to those described by Neill (1963) for N. beyeri. 



Rock microhabitats do not occur in the Coastal Plain range of N. 

 lewisi, and further studies of its ecology should be conducted in this 

 province. We can speculate, however, that bottom debris, roots, and 

 bank microhabitats replace rocks, and high oxygen levels and flow are 

 important factors in microhabitat selection. In any case, it would appear 

 that damming, stream clearing (snagging), or channelization would be 

 detrimental to N. lewisi. 



Home ranges were observed, using tagged animals, and are similar 

 in size to those that Shoop and Gunning (1967) alluded to in their 

 mark-recapture studies of N. maculosus and N. beyeri. It appears that 

 male N. lewisi have a larger home range than females, and that they 

 have different and longer periods of movement. Changes in movement 

 and microhabitat use appears to be seasonally regulated by temperature 

 and rainfall. Environmental data were not collected in a way that would 

 provide statistically valid analyses. 



Periodic high levels of mercury and other potential pollutants could 

 have long range effects on N. lewisi populations. However, there are no 

 data to show what these effects may be or at what concentrations detri- 

 mental effects take place (R. Hall, pers. comm.). The availability of such 

 data would be important in evaluating future conservation status of N. 

 lewisi. 



Microhabitats are manipulated by N. lewisi. The animals actively 

 develop a retreat under cover and maintain the area free from algae and 

 debris. This was observed in the laboratory and in the field. The method 

 of cleaning sand and gravel by taking it into the mouth has not been 

 reported for this genus. 



Pairing was observed in captive males during the breeding period, 

 and the more aggressive females permitted males to use the same retreat 

 areas at this time. Ashton and Braswell (1979) reported a male under a 

 nest rock and speculated that both males and females may participate in 

 nesting. 



Agonistic behavior increased between individuals after the nesting 

 season. Threat displays in both sexes include flared and waving gills, 

 and lip curls. When two N. lewisi are involved, false attacks are often 

 displayed prior to actual contact. This is followed by a bite that appears 



