EVIDENCE FOR OBLIGATE MONOPHENISM 
IN RELIQUIA SANTAMARTA , 
A NEOTROPICAL-ALPINE PIERINE BUTTERFLY 
(LEPIDOPTERA:PIERIDAE) 
By Arthur M. Shapiro 1 
Department of Zoology 
University of California 
Davis, California 95616, U.S.A. 
Introduction 
The phenomenon of seasonal polyphenism under photoperiodic 
control is now well established in a variety of butterflies, especially 
members of the family Pieridae (Shapiro, 1976a). Although it is 
expressed in nature primarily by multivoltine populations at low 
to middle altitudes in strongly seasonal mid-latitude climates, po- 
lyphenism has been found in a latent form in univoltine species 
which are ordinarily monophenic. These include species coevolved 
with vernal-ephemeral host plants ( Pieris virginiensis Edwards, 
Shapiro, 1971; P. napi microstriata Comstock, Shapiro, 1975a) or 
facing short growing seasons due to altitude ( Pieris occidentalis 
“calyce” Edwards, Shapiro, 1974) or latitude ( P.o . nelsoni Edwards, 
Shapiro, 1975b). To date no population of either the Pieris calli- 
dice Hiibner or P. napi Linnaeus complexes has been found to be 
obligately monophenic, although some P. napi (Yukon Territory 
and central New Mexico, Shapiro, 1976a) produce only more-or- 
less heavily dark-veined phenotypes. The ability of univoltine 
Pierines to produce phenotypes analogous to normal seasonal ones 
produced by their multivoltine relatives, when reared in photo- 
period-temperature regimes which do not occur in their natural 
habitat, has been interpreted (Shapiro, 1976a) as evidence for the 
derivation of univoltinism/monophenism from multivoltinism/ po- 
lyphenism in the course of adaptation to new or changing climates. 
'This work was made possible by grants from the National Geographic Society 
(USA) and the National Science Foundation (USA) and with the help of Colombian 
friends too numerous to mention. Special thanks go to Ms Adrienne R. Shapiro 
and Dr. Arthur S. Weston for their companionship and constant help afield in the 
Sierra Nevada. 
Manuscript received by the editor December 15, 1977. 
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