GENERATIONAL "CARRYOVER" AND THE SUPPRESSION OF SUBMARGINAL PATTERN ELEMENTS IN VERNAL PHENOTYPES OF PIERIS PROTODICE (LEPIDOPTERA: PIERIDAE) 1 Arthur M. Shapiro 2 The Checkered White butterfly, Pieris protodice Boisduval and LeConte, like many Pieridae exhibits a photoperiodically controlled seasonal polyphenism (Shapiro, 1968). The vernal-autumnal phenotype ("vernalis" Edwards), produced from larvae reared under September and October photoperiods, is characterized by heavy dark scaling on the veins of the hindwing beneath and by a series of chevron-shaped markings between these veins (figure la). This pattern is characteristic of the species-group to which P. protodice belongs, although it is reduced in summer phenotypes of multivoltine species and in both generations of the partially bivoltine P. sisymbrii Boisduval. In this species the chevron-markings, while never complete, are sufficiently recognizable to present a fades easily distinguishable from that of the P. napi species-group, in which only the veins are melanized. Specimens of P. protodice "vernalis" resembling P. sisymbrii in this character are occasionally taken wild, and very rarely individuals may occur in which the chevrons are completely suppressed. Examination of long bred and wild series of P. protodice reveals that the chevrons are composed of lines extending basad from the vein-tips and converging near the middle of the interspace; they frequently fail to meet and form a vertex. When the vein-lines are unusually heavy they may absorb the chevron-lines to the extent that the pattern is obscured (as in P. sisymbrii) or effectively obliterated (as in the extreme P. protodice figured by Shapiro, 1969). The bred male shown in figure Ib displays the usual manifestations of "chevronlessness." Prior to 1971 no "chevronless" P. protodice were produced in laboratory rearing. In July, 1971 a stock was established from 'Accepted for publication: October 17, 1972. Department of Zoology, University of California, Davis, California 95616. Ent. News, 84:294-298, 1973 294
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