The differences in life table between organophosphate-resistant and -susceptible lines of oriental fruit fly (Bactrocera dorsalis)

A life table, a detailed description of the mortality of a population giving the probability of dying and various other statistics at each age or period, is an important analytical and conceptual tool in ecological study, since it can be used to develop pest management strategies and mass rearing programs. Fruit flies (Diptera: Tephritidae) are very important economic pests of tropical agricultural crops in the world because of their wide host range, high climatic adaptability, and great reproduction potential. Fruit flies (Bactrocera spp.) resistance to organophosphate insecticides in the field were reported in Taiwan and in Europe. This problem increases the difficulty of pest management on these flies. Therefore, we want to study the life tables between organophosphate-resistant and -susceptible strains of oriental fruit fly (B. dorsalis) to develop pest management strategies. Changes in life tables of both strains due to variations of laboratory temperatures (15, 20, 25, 30 and 35°C) were studied. The developmental time from egg to adult decreased as the temperature increased. And the sensitivity degree of susceptible population is higher than the resistant population at 20, 25 and 30°C, although there are no differences in the expectation of life (ex) of both populations. In the future, we want to compare the reproduction strategies including net reproductive rate (R0) and intrinsic rate of natural increase (rm) in these two strains.