Notes on Breeding Period, Incubation Period, and Egg 



Masses oi Amby stoma jeffersonianum (Green) (Amphibia: 



Caudata) from the Southern Limits of Its Range 



Charles K. Smith ^ 



Department of Biology, 

 University of Kentucky, Lexington, Kentucky 40502 



ABSTRACT. — Observations on breeding and incubation periods of 

 Ambystoma jeffersonianum were made at three central Kentucky 

 ponds during 1980 and 1981. Breeding began in early January, 1980 

 and in early February, 1981. There were also substantial differences 

 between years in duration of the breeding period. During both years 

 hatching occurred over a two-week period between late March and 

 early April. Mean number of eggs per mass was 23.4 ± 13.5, and mean 

 mass dimensions (length x diameter, mm) were 43.1 ± 11.9 x 39.0 ± 

 8.6. There are indications that the number of eggs per mass for Ken- 

 tucky populations is greater than for more northern populations. 



INTRODUCTION 



Relatively little life history data exist for Ambystoma jeffersonia- 

 num (Green). Data published prior to Uzzell's (1964) definitive work on 

 the A. jeffersonianum complex may not, in fact, deal with A. jeffersoni- 

 anum. The species ranges throughout most of the northeastern United 

 States and reaches its southern limits in central Kentucky. Life history 

 data from Kentucky populations, since they are peripheral, should shed 

 light on factors that limit the species' distribution. Unfortunately, very 

 few published studies concern Kentucky populations. This note provides 

 observations on breeding, incubation periods, and characteristics of egg 

 masses of A. jeffersonianum in central Kentucky. To investigate annual 

 and local variation in breeding and incubation periods, observations 

 were made in three local ponds over a two-year period. 



STUDY SITES AND METHODS 

 Data were collected during 1980 and 1981 from three abandoned, 

 semi-permanent farm ponds in Jessamine County. Each pond had a sur- 

 face area of less than 288 square meters, and an average depth of 21 cm. 

 Pond 1 is located 0.4 km north of Pond 2, and Pond 3 is approximately 

 1.5 km northwest of Pond 1. Ambystoma jeffersonianum is the only 

 ambystomatid salamander that regularly uses any of the ponds, although 

 over a four-year period I have occasionally observed eggs and larvae of 

 A. texanum in Ponds 1 and 2. 



• Present Address: Department of Biology, University of North Carolina, Chapel Hill, 

 North Carolina 27514. 



Brimleyana No.9: 135-140. June 1983. 135 



