NATURAL MORTALITY OF THE TEAK BEEHOLE BORER, (XYLEUTES CERAMICUS WALKER AT MAEGAR SEED ORCHARD, PHAYAO)

Abstract

A study of the natural mortality of the teak beehole borer (Xyleutes ceramicus Wlk.) was conducted at Maegar Seed Orchard, Phayao province. The partial ecological life table was contructed from this study. This reveals that the highest generation mortality occurred in the stages of eggs and newly hatched larvae before boring into teak. During these stages, percentage mortality was 18.34 and 80.84, respectively and ants were found to be the principal predators. After successfully boring into the teak, mortality of young larvae living in the bark was also found to be high, 0.591% in April and 0.127% in May. Once the larvae had bored into the wood, the mortality rate dropped significantly to around 0.001-0.02%. Abiotic and biotic factors play an important role on the larvae inside the stem. Pupal mortality of 0.008% was caused by ants, fungi and pathogen. The emergence of the first year was 0.017%. Some borers were able to prolong their life cycles for up to 2 years, although based on the average number of eggs produced, only 0.002% of the eggs developed to 2nd year larvae. The successful reproduction of the beehole borer was found to be considerably lower than expected in this study; one female, for instance, produced only 2 months to the next generation. However, this can be attributed to the controlled conditions that were necessary in order to conduct the study and cannot be taken as representing the reproduction rate in natural habitat and conditions.