GENETIC CONSTRAINTS TO LIFE-HISTORY EVOLUTION IN THE PITCHER-PLANT MOSQUITO, WYEOMYIA-SMITHII

Life-history theory relies heavily an the hypothesis that genetic trad eoffs among the components of fitness constrain their independent evol ution and joint maximization. Herein we show that selection on preadul t development time in the pitcher-plant mosquito, Wyeomyia smithii,, l eads to a correlated response in cohort mean generation time but no co rrelated response in survivorship, fecundity. or cohort replacement ra re. Lines selected for fast development achieve a higher capacity for increase (r(c)) than lines selected for slow development, independentl y of larval density. These results imply that tradeoffs due to underly ing antagonistic pleiotropy affecting growth, development, survivorshi p. and reproduction are not necessary constraints to life-history evol ution. Previous work with W. smithii has shown a positive generic corr elation between development time and a general, genetically coordinate d diapause syndrome. We propose that the observed nontradeoffs among t he components of r(c) may be subsumed into an even more fundamental tr adeoff between performance during the summer generations and synchroni zation of development and reproduction with the changing seasons, Cons equently, critical tests of genetic tradeoffs as a constraint to the i ndependent evolution or simultaneous optimization of fitness component s may need to consider the seasonal context.