Interannual Variation in Clutch and Egg Size of the Banded Darter, Etheostoma zonale
We found significant variation among years in the reproductive life-history traits of a single population of the Banded Darter, Etheostoma zonale from the Duck River drainage of Tennessee. Standard length-adjusted average clutch size varied by a factor of 1.38 among years and adjusted ripe egg mass by a factor of 1.21. Interannual variation in E. zonale's clutch size appears to be less extensive than is geographic variation reported previously, and egg size is generally less variable than is clutch size, both geographically and temporally, as has been predicted from life-history theory.Abstract
Regression of clutch size on standard length. Dashed line is least-squares linear regression line for 1977 (Ŷ = 3.53X − 95.73, R2 = 0.671, n = 24, P < 0.0001); dotted line: 1978 (Ŷ= 3.56X − 79.22, R2 = 0.686, n = 24, P < 0.0001); alternating dash-dot line: 1981 (Ŷ = 4.33X − 111.92, R2 = 0.873, n = 24, P < 0.0001). For all years considered together: Ŷ = 3.52X − 84.47, R2 = 0.651, n = 72, P < 0.0001
Regression of mean ovum mass on standard length. Dashed line is least-squares linear regression line for 1977 (Ŷ = 9.34X + 208.64, R2 = 0.492, n = 6, P = 0.1202); dotted line: 1978 (Ŷ = 7.48X + 304.48, R2 = 0.479, n = 5, P = 0.1955); alternating dash-dot line: 1981 (Ŷ = 11.07X + 55.76, R2 = 0.687, n = 10, P = 0.0030). For all years considered together: Ŷ = 11.72X + 77.66, R2 = 0.455, n = 21, P = 0.0008