[Population life parameters and relative fitness of alpharmethrin-resistant Bactrocera dorsalis strain]

Based on the observation of the development and reproduction of experimental populations of alpharmethrin-resistant and susceptible Bactrocera dorsalis strains at (28 +/- 2) degrees C, the life tables of the populations were established, and the differences in the relative ecological fitness of the two strains was analyzed. The results showed that comparing with alpharmethrin-susceptible B. dorsalis strain, the resistant one had longer durations of development stages, average generation, and previposition, its fecundity was not stable and lower, and the hatch of eggs and the emergence of adults were depressed. The fecundity of the susceptible and resistant strains was 324.0 and 240.7, respectively. Based on the life tables, the population trend index (I) of resistant strain was 79.10, while that of susceptible strain was 116.97. The net reproduction rate (R0) and the intrinsic rate of increase (rm) of resistant strain were 1414.00 and 7.9463, while those of susceptible strain were 2184.00 and 8.3809, respectively. The relation fitness of resistant strain was only 0.6474. All of the results revealed that the resistant strain was at an obvious inferior position of reproduction and development.