64 
Psyche 
[Vol. 90 
tant and possibly adequate to account for reproductive isolation. (It 
is conceivable that pheromones could be physiologically coupled to 
phenotypes such that the most phenotypically deviant females 
would also be pheromonally abnormal.) 
The control of pattern in Precis has been studied by Nijhout 
(1980a, b), who has shown that all of the wing pigments in P. coenia 
are melanins and that the ocelli are determined by well-defined foci 
in the early pupal wing. His work does not permit a causal analysis 
of how pupal chilling phenocopies the normal phenotype of nigro- 
suffusa, though the phenocopy “straw” has been linked functionally 
to its genocopy in Drosophila (Seybold, Meltzer, and Mitchell, 
1975). In Shapiro’s (1981) model of the evolution of phenotypic 
plasticity, a genetic basis for bandlessness could be established by 
selection of modifiers bringing the latent ''schraderr response to the 
surface under normal developmental temperatures. The derivative 
character of bandlessness is shown clearly by its variable penetrance 
(especially in females) in pure nigrosuffusa populations. But how 
did it become virtually fixed? Discrimination by male coenia against 
bandless females, even genotypicaly normal ones with intact wings, 
should lead to selection against any bandless allele, however ori- 
ginated. Under the conventional model for enhancement of pre- 
zygotic reproductive isolating mechanisms in secondary sympatry, 
one could rationalize bandlessness as a device protecting the gene 
pool of nigrosuffusa. This, however, presupposes a disadvantage to 
Table 1. Success of cold-shocked female Precis coenia in attracting courtships by 
wild males in field tests in northern California. 
Type of female 
Number of 
99 
Total 
releases 
Number of 
$9 mated 
Number of 
courtships 
(i) essentially 
- 
unaltered 
phenotype 
18 
42 
6 
31 
(ii) bandless, ocelli 
unaltered 
20 
55 
5 
27 
(iii) bandless, ocelli 
obsolete 
8 
17 
0 
8 
Totals 
46 
1 14 
1 1 
66 
'-test for courtship proportions, (i) \’.v. (ii + iii): z 
= 2.7845 (significant at 0.01) 
