Fitness of two Trichogramma species and one ogrammatoidea reared on the eggs of the diamondback moth Plutella xylostella
Author of the article:SHU Rui-Hao1,4** KONG Qing-Hua2 ZHANG Wei-Dong2 SHENG Hui2 WANG Hong-Tuo1HUANG Shou-Shan3*** QI
Author's Workplace：1. State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; 2 Laolai Agriculture and Sideline Base of Shenyang Military Area Command in Nehe City of Heilongjiang Province, Nehe 161346, China; 3. South China Agricultural University, Guangzhou 510642, China; 4. University of Chinese Academyof Sciences, Beijing 100049, China
Key Words：Trichogramma japonicum, Trichogramma chilonis, Trichogrammatoidea hypsipylae, Plutella xylostella, parasitizing fitness, life table
Abstract： [Objectives] To study the feasibility of using eggs of the diamondback moth (DBM) Plutella xylostella as an alternative host to C. cephalonica for Trichogramma, and determine feasibility of raising these parasitoids on the eggs of P. xylostella. [Methods] Based on the life table analysis of population ecology, the parasitizing fitness of Trichogramma japonicum Ashmead, T. chilonis Ishii and Trichogrammatoidea hypsipylae Nagaraja on the egg of P. xylostella were studied quantitatively. [Results] Life table parameters showed the net reproductive rate (R0), intrinsic increase rate (rm), finite increase rate (λ) and mean generation time (T) of T. hypsipylae, were 9.10, 0.2177, 1.2432 and 10.1432, respectively, whereas those of T. japonicum were 4.66, 0.1633, 1.1809 and 9.2532. Fecundity of T. hypsopylae was highest with 15.4 eggs laid per female, compared with T. japonicum 10.0 and T. chilonus 8.9. On the other hand, the reproductive potential of T. chilonis on DBM eggs was much lower than those of the other two parasitoids, whose rm and sex ratio (female/male) were as low as 0.0338 and 0.174, respectively. [Conclusion] The results revealed that T. hypsipylae and T. japonicum had much higher preference for DBM eggs than T. chilonis. The fact that the intrinsic rate of increase (rm) of T. hypsopylae and P. xylostella were so close (0.2177 for T. hysopylae and 0.239 for P. xylostella) suggests that the latter could be a suitable host for the former. In contrast, the lower parasitic fitness of T. chilonis on DMB eggs was insufficient to sustain its experimental population. We conclude that DBM eggs are not an ideal intermediate host for T. chilonis.