Ecobiology of the Common Evening Brown, Melanitis leda Linn. (Lepidoptera: Rhopalocera: Nymphalidae: Satyrinae)

Abstract

The common evening brown butterfly, Melanitis leda Linn. is seasonal in its occurrence at Visakhapatnam (17o 42' N and 82 18' E), South India, during September to March. It utilizes Brachiaria distachya (Linn.) Stapf. for oviposition and as larval host. It lays eggs singly. The hatched larvae show five instars. It shows light green colour with a pair of horns in the head region. Pupa shows green colour with a mid-dorsal dark green line. The developmental time from egg to adult emergence was 27 – 35 (31.40 ± 3.43) days in the laboratory conditions with 28 ± 20 C, 80 ± 10% relative humidity, 12 – 14 h day-length. The early lifestages (eggs, larvae, pupae) are evident on B. distachya for a period of 150 days during September to January, thus producing an estimated three to four overlapping broods per year. There was a relatively high frequency of the early lifestages during October to December corresponding to rainy and winter seasons. Probably this Satyrid may require more moist and shady conditions for its occurrence and reproduction throughout the year. Such conditions were not available in the study biotope throughout the year, hence its occurrence over a limited part of the year. The larvae were efficient in consuming and utilizing the host leaves as indicated by the food utilization and nutritional indices of different instars. Approximate digestibility (AD) 96.66% - 57.24%, efficiency of conversion of ingested food to body substance (ECI) 6.66% - 36.52%, efficiency of conversion of digested food to body substance (ECD) 6.89% - 51.76%