Body sizes,development rates,and genome sizes among Calanus species

Data on embryonic and larval development times (D) of Calanus species are analysed using Blehrádek's temperature (T) function, D = a (T – )^b, with b = – 2.05 as in previous studies. Among these species, for embryonic duration varies directly with temperatures in their geographical ranges and a is related to egg diameter. Using and b from embryonic durations, the fitted values of a for older stages are related to body sizes. Roughly estimated nucleus numbers in single adult females of C. finmarchicus, glacialis and hyperboreus were similar at 72 000, 85 000, and 96 000 respectively. Genome sizes (2C) of adult females are ca. 13 pg DNA in C. finmarchicus and pacificus, ca. 17 pg in C. sinicus, ca. 21 pg in C. helgolandicus and marshallae, and ca. 25 pg in C. glacialis and hyperboreus. These correspond roughly to body sizes and temperature-corrected development rates, quite precisely so in the sibling pair C. finmarchicus and C. glacialis, suggesting that, given similar nucleus numbers, there is nucleotypic control of whole-organism characteristics.