EUROPEAN JOURNAL OF ENTOMOLOGY

Eur. J. Entomol. 116: 123-132, 2019 | DOI: 10.14411/eje.2019.014

Quantitative response to photoperiod and weak coupling between seasonal morphs and diapause regulation in the Asian comma butterfly, Polygonia c-aureum (Lepidoptera: Nymphalidae)Original article

Satoshi HIROYOSHI¹, Makio TAKEDA², Takayuki MITSUNAGA³, Gadi V.P. REDDY⁴

¹ Laboratory of Applied Entomology, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-0054, Japan; present address: 202 Corpo Mankyu, 1-23-8 Nodamachi, Kawagoe, Saitama 350-1115, Japan; e-mail: satoshi_hiroyoshi@yahoo.co.jp

² Graduate School of Agricultural Science, Kobe University, 1-1 Rokko-dai, Nada, Kobe 657-8501, Japan; e-mail: mtakeda@kobe-u.ac.jp

³ Central Region Agricultural Research Center, National Agriculture and Food Research Organization, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8666, Japan; e-mail: aeiou@affrc.go.jp

⁴ Montana State University, Western Triangle Agricultural Research Center, 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425, USA; e-mail: reddy@montana.edu

Reproduction and wing patterns (shape and colouration) in Polygonia c-aureum L. (Lepidoptera: Nymphalidae) are regulated by both photoperiod and temperature experienced during the immature stages, which result in the development of summer or autumn forms. The critical day length for this seasonal change in form was 13.5L : 10.5D at 21°C and 13L : 11D at 25°C. We investigated the connection between seasonal form and female reproduction. Under a 15L : 9D photoperiod at 21°C, reproductively active summer form butterflies are produced, whereas under an 8L : 16D photoperiod at 21°C autumn form butterflies with a strong tendency to enter diapause were produced. On the other hand, under the critical day lengths at 21 or 25°C, autumn form butterflies developed with a weak tendency to enter diapause. When the adult butterflies were transferred from a critical or a short photoperiod to a long photoperiod shortly after emergence, the former were more likely to terminate diapause than the latter. If individuals are reared throughout their entire life cycle under a short photoperiod at 21°C, all the adults have a strong tendency to enter diapause. These results reveal the quantitative effects of photoperiod on diapause in this butterfly and strongly indicate that the determination of the autumn form and induction and maintenance of diapause are not rigidly coupled, at least under laboratory conditions.

Keywords: Lepidoptera, Nymphalidae, Polygonia c-aureum, diapause induction, photoperiodism, ovary, reproduction, seasonal form

Received: December 17, 2018; Revised: March 21, 2019; Accepted: March 21, 2019; Published online: April 26, 2019  Show citation