A study of the effect of temperature and photoperiod on the phenotypic variation of two pierid butterfly species, Appias libythea and Cepora nerissa was conducted during January to December 2013 in Savar, Dhaka, Bangladesh. Both species of butterflies were found two distinct phenotypic forms i. e. wet season form (WSF) and dry season form (DSF) that alternate according to the season. WSF of both species were observed in wet season (March to October) when photoperiod was >12 hours at relatively high temperature, whereas DSF was observed in dry season form (November to February) when photoperiod was <12 hours at relatively low temperature. The WSF of A. libythea, black apical markings of the dorsal side of forewings were darker and broader than DSF and there are black spots streaks at the end of the hind wing veins which were absent in DSF of A. libythea. The ventral side of entire forewing and hind wing of WSF veins broadly black margined which were absent in DSF of A. libythea. In the WSF of C. nerissa, the band of the forewing and small black area became darker and broader than the DSF. Yellow spot of ventral side of WSF was larger than the DSF of C. nerissa. Abundance of WSF was much higher than DSF and fluctuation pattern was bimodal for WSF adults of both species. In both species, the turnover of DSF to WSF found to occur around the March when rising temperature and photoperiod as well as increased food plants while the transition of WSF to DSF was found around October when declining temperature and photoperiod as well as decreased food plants.
A.T.M.F.Islam, M.H. Islam, M.M. Rahman, A.S.M. Saifullah, Akira Yamanaka. Effects of temperature and photoperiod on the phenotypic variation of two Pierid Butterfly Species. J Entomol Zool Stud 2015;3(1):208-212.