In the Y and O populations, significant average dominance effects for the
preadult developmental time and wet body weight of males as well as the early fecundity and the total fecundity of females were observed.
For protandry to evolve, all these models assume or assert that (1) the independent evolution of male and female
preadult development time is possible, i.e., that protandry is a heritable trait and (2) populations are univoltine or at least comprised of discrete, nonoverlapping generations.
Preadult stages of the dominant fishes seem to adjust well to this new resource: in the Parana River larvae of 10 out of 15 fish species surveyed between October 2000 and March 2001 feed regularly on golden mussel veligers (Paolucci et al.
But trade-offs governing fitness in the
preadult stages have only recently received significant attention (Partridge and Fowler 1992; Chippindale et al.
Since the data for
preadult survival show that there was a tendency for relatively [TABULAR DATA FOR TABLE 1 OMITTED] greater pre-adult survival of the large lines at 25 [degrees] C but not at 18 [degrees] C, the interaction between temperature and selection regime for lifetime progeny production cannot be an artifact of differences in pre-adult survival.
Finally, photoperiodic response and
preadult development time are genetically correlated within populations but these two traits have evolved independently over the range of W.
According to estimates of annual adult mortality (6.07%),
preadult mortality (83.86%), and longevity (21-22 yr) of the Spanish Imperial Eagle, each female must produce [approximately equal to]0.75 chicks per year to replace herself (Ferrer and Calderon 1990).
Although the selective advantages accruing to larger individuals in colder environments are not completely clear, it seems likely that the longevity and fertility of adults are improved by large body size, while the achievement of large body size imposes penalties such as high
preadult death rates and a late age of first reproduction (e.g., Roff 1992; Stearns 1992).
trifolii, with overlapping generations, a more rapid
preadult developmental time usually contributes to increased fitness (Lewontin 1965; Charlesworth 1980).
Individuals of Wyeomyia smithii complete their entire
preadult development within water-filled leaves of the insectivorous pitcher plant, Sarracenia purpurea L.
melanogaster, Mukai (1964) measured the
preadult viability of second chromosome mutation-accumulation lines at 21 [degrees] C and 25 [degrees] C, and found no GEI between these two temperatures.
1994; Jenkins and Hoffmann 1994), but only little on
preadult stages.