No abstract

The development times to hatching (D) of eggs of eleven species of copepods are closely described as functions of temperature (T) by Bělehrádek's temperature function, D = a (T - α) using the assumption that the same value of b applies to all species. The value of a is related to egg diameter among three species of Calanus, and is unaffected by the greater opacity (presumably yolkiness) of eggs of C. hyperboreas. The value of a remains as the "real" indicator of temperature adaptation, and is closely and linearly related to estimates of environmental temperature based on mean annual temperatures within the range of each species between the pole and South America, along the east coast of the Americas.

It has been argued (McLaren, 1963, 1965) that reproduction and development of copepods may be physiologically (rather than trophically) determined when food is sufficiently abundant: thus, under these conditions the rates of development and egg production, and the total number of eggs laid by a female in her lifetime vary only with the physical factors of the environment such as temperature, salinity and pressure, temperature being by far the most important. This paper is part of a continuing study of the physiological controls of growth and development as part of a general investigation on productivity of marine zooplankton.

No abstract

Data on embryonic and larval development times (D) of Calanus species are analysed using Bl1ehrdek's temperature (T) function, D = a (T -L)b, with b = -2.05 as in previous studies. Among these species, a for embryonic duration varies directly with temperatures in their geographical ranges and a is related to egg diameter. Using a 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 96000 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.