PHOTOPERIODIC CONTROL OF DEVELOPMENT AND PHENOTYPE IN A SUBARCTIC POPULATION OF PIERIS OCCIDENTALIS (LEPIDOPTERA: PIERIDAE)

• Published in: The Canadian Entomologist
• Main Author: Shapiro, Arthur M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1975
• Subjects: Insect Science; Molecular Biology; Physiology; Ecology, Evolution, Behavior and Systematics; Structural Biology; Fairbanks; Subarctic; Alaska
• Online Access: http://dx.doi.org/10.4039/ent107775-7; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0008347X00033332

Abstract Pieris occidentalis nelsoni W. H. Edwards from Fairbanks, Alaska, was reared under a variety of photoperiod–temperature regimes. The source population is presumably univoltine and monophenic, with a phenotype resembling the vernal one produced by multivoltine, diphenic P . o . occidentalis Reakirt in Colorado and California. Photoperiods of 10 or 15 h produced 100% diapause pupae at 15 °C and circa 65% at 25 °C. Under continuous light 22% diapaused at 15 °C and < 1% at 25 °C. About 20% of non-diapause pupae produced adults resembling the estival phenotype of P . o . occidentalis , which is unknown in wild P . o . nelsoni . Although nelsoni is more likely to diapause than the nominate subspecies from the Sierra Nevada, its potential for direct development and polyphenism is interpreted as evidence that it is derived from a multivoltine ancestor.