Kinosternon Reproductive Cycle 45 



lutea (2.50±0.87; N = 82). Twelve clutches examined by Einem (1956) 

 and Lardie (1975) averaged 2.33 (Range = 1-3). Nicol's (1970) record of 

 a 6-egg clutch probably represents the maximum for the species. As 

 Einem's (1956) data suggest, clutch size is positively correlated (p < 

 0.01) with plastron length and increases an average of one egg for each 

 20.8 mm increase in PL (Figure 5). No seasonal trends in clutch size were 

 identifiable. 



ANNUAL REPRODUCTIVE POTENTIAL 

 The ovaries of four females bore two distinct sets of corpora lutea. 

 Clutch sizes of these turtles were 3 (larger set of corpora lutea) and 2 (6 

 October; 95.4 PL), 2 and 2 (5 January; 101.3 PL), 1 and 1 (20 April; 77.8 

 PL), and 5 and 4 (20 June; 95.4 PL). All but the last of these also had a 

 set of pre-ovulatory follicles > 10 mm diameter. The ovaries of the first 

 female suggest that following the first clutch of the reproductive season 

 (late August to early September ?), she might possibly nest again in Oc- 

 tober. If her indicated inter-nest period of about 2 months were main- 

 tained, 6 clutches could be produced annually. This relatively long inter- 

 nest interval presumably allows for nearly complete luteal regression bet- 

 ween ovulations and may explain why only 4 of 84 females had more than 

 one set of identifiable corpora lutea. 



Mature females certainly produce at least three clutches each year. 

 Einem (1956) also suspected that three clutches might be produced an- 

 nually, and Lardie (1975) reported a captive central Florida female (115 

 mm CL) which produced three clutches of three eggs each on 7 March, 9 

 June, and 16 November 1969. If each clutch averages 2.5, average annual 

 reproductive potential is at least 7.5. Field studies will be necessary to 

 determine the actual number of annual clutches. 



Reproductive effort per clutch was estimated by the ratio of mean 

 clutch weight (mean egg weight X mean clutch size) to mean total female 

 weight. Clutches in Kinosternon baurn average 8.23 per cent (4.45X2.50X 

 100/135.1) of female weight. Unfortunately, similar estimates are 

 available for no other kinosternid turtle. 



ACKNOWLEDGMENTS. — I thank Dr. Walter Auffenberg for making 

 the Florida State Museum facilities available to me. Thanks are also due 

 Diderot Gicca, Howard Kochman, Peter Meylan, and Brick Rainey for 

 able field assistance. Numerous other people diligently retrieved 

 specimens killed while crossing roads. Dale R. Jackson offered valuable 

 comments on an early draft of the manuscript. My wife, Sheila, typed the 

 manuscript. 



