GENETIC AND PHYSIOLOGICAL FLEXIBILITY 469 



APPEIMDIX B: MEASURIIMG INDIVIDUAL (PHYSIOLOGICAL) 

 FLEXIBILITY 



Physiological flexibility, a|^ can be estimated (1) by test— retest 

 correlation, (2) indirectly by subtracting genetic variance, and (3) by 

 acclimation tests: 



« 

 2 2 2 



(l)rtt =-^^r-^= l--4^ (from Falconer, 1960) 



(2) Qg = Op — {o\ + cr^^ ) if general environmental variance is 



not large 



(3)4s=^B 



vv^here ag is the variance in tolerance betw^een prior exposure 

 temperatures calculated from the analysis of variance of tolerances 

 following exposure to various temperatures: 



The symbols a^, aj , and ol are obtained from the mean squares 

 and give estimates of the variances between all three classes (overall), 

 between 10° C and 18 + 24° C and between 18 and 24° C. Note that 

 kj is the number of animals per class, and k2 is the harmonic mean 

 of k, and 2ki , thus k2 == l.Skj . 



The third measure is most appropriate in the context of 

 individual adaptation to temperature stress. 



