|SREL Reprint #0816|
Variation in Reproductive Characteristics of Aquatic Turtles
Whitfield Gibbons, Judith L. Greene and Karen K. Patterson
size (N=473) and frequency were examined in five species of turtles from South
Carolina in an effort to relate reproductive attributes to other life history
and environmental characteristics. In
determining the relationship between body size and clutch size, body mass and
length were found to be equally satisfactory expressions of body size.
Logarithmic transformations of mass had little effect on the correlation
between body size and clutch size.
linear model of the relationship between body size (plastron length) and clutch
size explained 67% of the variation for Pseudemys floridana, 56%
for P. scripta and 25% for Sternotherus odoratus.
A linear model was not useful describing the pattern in the other two
species (r2=0.5, Kinosternon subrubrum and .08, Deirochelys
reticularia). However, within each of the five species, maximum clutch
sizes of the smallest individuals are never as large as the maximum clutch sizes
of the largest individuals.
sizes within a species did not vary significantly among years or populations if
the effect of body size was removed. Clutch
size varied among months in all species, with a trend of decreasing clutch size
during the egg-laying season apparent for P. scripta, P. floridana
and K. subrubrum.
of four species were recorded laying more than one clutch within a single egg
laying season. The proportion of
adult females known to have multiple clutches within a year varied for each
species. Monthly timing of egg
laying was not consistent for an individual female from year to year.
No relationship could be identified between clutch frequency and body
size in K. subrubrum or P. scripta, the only species
for which adequate samples were available for such an analysis.
SREL Reprint #0816
Gibbons, J.W., J.L. Greene, and K.K. Patterson. 1982.
Variation in reproductive characteristics of aquatic turtles.