The Demographic of Brontispa longissima variety of celebensis Gestro (Coleoptera: Chrysomelidae) on Mapanget Tall Coconut and Brown Dwarf Coconut

Abstract

Brontispa longissima variety of celebensisis considered an important pest on coconut trees. Basic information such as the biology and the life table of the species is extremely important in the effort to control its attack. The life table of B. longissima variety of celebensis on Mapanget Tall Coconut (MTC) and Brown Dwarf Coconut (BDC) can be examined in laboratory. The study aimed at examining the biology and the life table of B. longissima variety of celebensis on MTC and BDC. The study was conducted at Entomology Laboratory of Indonesia Palmae Research Institute, Manado, from June to November 2012. The parameters examined during the study consisted of the followings: 1) the development period from larvae of each instar into adult, 2) the longevity of adult, and 3) the number of eggs laid. The results of the study show that the young leaves of DMT are more suitable to support the life of B. longissima variety of celebensis compared to the young leaves of GRA, and this could be seen from the shorter immature development periods, the higher number of eggs laid, and the longevity of adult. B. longissima variety of celebensisis more suitable to live and grow on the young leaves of DMT than on the young leaves of GRA. This could be seen from the average rm value which was higher on DMT leaves, that was 0.123 individual per adult per day, and mean generation time (T) which was 35.28 days, as compared to the rm value on GRA leaves, that was 0.108 individual per adult per day, and mean generation time (T) which was 39.61. The rm value shows the suitability of the host plants to increase the population of arthropods by considering the development periods, fecundity, longevity, survivorship, and sex ratio.