Suitability of Chinese oak silkworm eggs for the multigenerational rearing of the parasitoid Trichogramma leucaniae
Authors: Yang-Yang Hou
Asad Ali
Nicolas Desneux
Lian-Sheng Zang
Xuan-Ye Wen
Wei Xu
Journal: PLoS ONE (2020)
Discipline: Multidisciplinary
Keywords: Trichogramma leucaniae; biological control agent; soybean pod borer; Antheraea pernyi; mass production
Affiliations: Institute of Biological Control, College of Plant Protection, Jilin Agricultural University, Changchun, China., General Station of Forest and Grassland Pest Management, National Forestry and Grassland Administration, Shenyang, China., INRAE, CNRS, UMR ISA, Universit√© C√¥te d'Azur, Nice, France., Department of Agriculture, Abdul Wali Khan University, Mardan, Pakistan.

Abstract:  Trichogramma leucaniae is believed to be an efficient biological control agent for controlling the soybean pod borer [SPB; Leguminivora glycinivorella]. The large eggs of Chinese oak silkworm, Antheraea pernyi, are one of the best alternative host for mass production of Trichogramma. However, they are considered poor host for the growth and development of T. leucaniae. Here, we determine the feasibility of successive rearings of T. leucaniae on the large eggs for eight generations and evaluated their capacity of parasitizing SPB eggs of different ages. In the first four generations, the suitability of T. leucaniae reared on large eggs exhibited a significant increasing tendency and then decreased with the successive generations thereafter. The percentage of parasitized eggs and number of emerged adults per egg were increased from 40.0% and 10.8 adults/egg in F1 generation to 86.7% and 36.4 adults/egg in F4 generation respectively. In addition, T. leucaniae reared on A. pernyi for four generations significantly parasitized more SPB eggs regardless of egg age compared with those reared on Corcyra cephalonica eggs. These results provided useful information on the feasibility of mass production of T. leucaniae by reared for successive generations on A. pernyi large eggs. 

Retracted: No

PubPeer comments:
 I have several concerns regarding the supplementary data of this article: -Why are there gradually more data from F1 to F4 and then gradually less from F4 to F7? -Data are duplicated or partially duplicated for each row, example: Table1, Pre-emergence time (day), F1:  14.52, 13.86, 13.94, 14.52, 13.86, 13.94 This is the case for each generation of each 4 variables. -The table for Figure 1 doesn t provide raw data, but ratios. -Why are sheet 2 and 3 empty? should they contain data? , 
 Can the authors explain why there is an increasing number of samples for F1-F4 and a decreasing number from F4 to F7, and why data are duplicated twice per row?  , 
 #2 As for why data are duplicated twice per row? Reply: A mistake when entering the numbers from the datasheets. We have fixed this mistake in a revised file. Fortunately the conclusions of the study remain the same as statistical values are similar based on the correct data. , 
 As for your concerns that why the emergence and parasitism significantly decease after 5 generations, seemingly it is a unnormal result indeed. We are also interested in these results, and a NSFC project has been granted in 2021 to explore the potential mechanism. Trichogramma parasitoids usually lay more than 50 eggs in the same egg of Chinese oak silkworm, and the adults will finish mating inside the host egg before they emerge from the egg. Therefore, presently I speculate that it is possible connected with the inbreeding of the offspring from the same mother parasitoids for multi-generations. As for why data are duplicated twice per row? Reply: A mistake when entering the numbers from the datasheets. We have fixed this mistake in a revised file. Fortunately the conclusions of the study remain the same as statistical values are similar based on the correct data.  ,