278 
Psyche 
[June-September 
(Lorkovic used pupal weight to estimate time of breaking 
of diapause. — A.M.S.) It must therefore be taken that the 
“heterodynamic sensitive period” sets in only after the 
completed latency. (Compare Papilio zelicaon Lucas, 
Shapiro, 1976. — A.M.S.) There are species in which the 
duration of the pupal dormancy shows great lack of uni- 
formity, varying from 1-8 years, without the difference 
being reflected at all in the markings of the butterflies . . .” 
Indications of the same phenomena are apparent in temperature- 
manipulation experiments with the aforementioned P. protodice 
and C. eurytheme, which had been thought to employ photoperi- 
odic cues alone. In both species vernal phenotype is irreversibly 
determined by short days (actually long nights), regardless of 
temperature and with no linkage to diapause (there are no obligate 
diapausers in P. protodice, and C. eurytheme has no diapause at 
all). However, as in both A. levana and P. n. venosa, long-day 
animals can be induced to develop the full vernal phenotype by 
pupal chilling. Examples are shown in Fig. 2. That these responses 
have been missed in the past is not surprising; they are difficult to 
work with. In a given group of sibs a few individuals will respond 
strongly to a given treatment, while others respond slightly or not at 
all. It is difficult to keep track of precise pupation times for large 
numbers of individuals and to obtain statistically meaningful num- 
bers of even-aged pupae for treatment, and the precise characteriza- 
tion of the responses will take several years, just as it did for the 
Nymphalid Nymphalis urticae (L.) (history reviewed in Shapiro, 
1976). However, it is already clear that there is considerable 
intrapopulational variability in the timing of the “sensitive period,” 
that it is quite short (there is no statistical difference in the 
distribution of phenotypes in batches of P. protodice chilled at the 
same age and held for 1, 2, 3, or 4 weeks), and that the mean 
responses among geographic conspecific populations differ. 
Precisely the same phenomena emerge in previous studies of 
phenotypic plasticity which is not involved in regular seasonal 
polyphenism: Aricia spp. (Hoegh-Guldberg, 1974a, b; Jarvis, 1974) 
(Lycaenidae); various moths (Kettlewell, 1963); and especially the 
“elymi” series of aberrations in Vanessa spp., and similar aberra- 
tions in Nymphalis spp. (all Nymphalidae; see Shapiro, 1976). These 
temperature-induced variations are “morphoses” (Schmalhausen, 
