Preliminary Study on Shelf Life of Artificial Feed of Chilo suppressalis

In order to preliminarily explore the preservation effect of ordinary refrigerator( 4℃) on artificial diet of Chilo suppressalis,the effects of artificial feed preserved at refrigerator for different time on percentage of pupation and pupa weight of C. suppressalis were investigated to understand the impact of long-term storage of artificial feed on the growth and development of C. suppressalis. The results showed that the percentage of pupation of C. suppressalis fed with artificial diet that had been stored in refrigerator for 40 d( T40) was highest( 67. 1%),followed by CK( 1 d,63. 5%),and the percentage of pupation of C. suppressalis fed with artificial diet that had been stored in refrigerator for10 d( T10) was 61. 9%. No significant difference was found in percentage of pupation among the treatment groups( P > 0. 05). The female pupa weight of the short-term preservation treatment group( 71. 9 mg) was significantly larger than that of the long-term preservation treatment group( 66. 1 mg)( P < 0. 05),and was insignificantly different from that of CK( P > 0. 05). The male pupa weight of the short-term preservation treatment group( 51. 2 mg) was significantly larger than that of CK( 47. 7 mg)( P < 0. 05),and the male pupa weight of the long-term preservation treatment group was slightly larger than that of CK( P > 0. 05). In conclusion,the artificial diet of C. suppressalis can be stored for at least 40 d in refrigerator( 4℃).

Screening of Slow Release Solvents for Plant Volatiles

[Objective] The paper was to study the slow release effects of eight common kinds of slow release solvents on n-hexane, and to provide a reference for the construction of slow release system of attractants or repellents synthesized by plant volatiles. [Method] The effect of slow release solvents on volatile quantity and release rate of n-hexane was compared by weight loss method. [Result] Under indoor natural conditions [(22±2) ℃,RH 50%±10%], the slow release effect of lubricating oil on n-hexane was the best, followed by liquid paraffin. The best ratio of slow release solvent(lubricating oil and liquid paraffin) and n-hexane was 5∶1 and the best mixing time was 3 h, which improved the slow release effects of n-hexane by6.3 and 4.7 times, and prolonged the half-life of n-hexane by 1.3 and 1.0 times, respectively. Slow release solvents mainly affected the post-half-life period of n-hexane, and the release rates of n-hexane mixed with lubricating oil and liquid paraffin were decreased by 10.4 and 7.7 times, respec-tively. During the half-life period, the release rates of n-hexane were decreased by 1.3 and 1.0 times, respectively. [Conclusion] Two kinds of slow release solvents with good slow release effect on volatile n-hexane are screened out, and the proportion and mixing time of slow release solvent and volatile are determined, which will provide technical support for the construction of plant volatile slow release system.

Disruption of a microvitellogenin gene impairs eggshell formation in Mythimna separata

Microvitellogenin(mVg)belongs to the lepidopteran-specific lipoprotein_11 super family and is thought to be involved in insect reproduction.However,the function of mVg in reproduction has not been established.In this study,we identified and characterized MsmVg in Mythimna separata,a destructive insect pest of grain crops.MsmVg is comprised of a 1,310 bp open reading frame(ORF)encoding 437 amino acids.Structural analysis showed that MsmVg contains three conserved domains in the lipoprotein_11 super family,including the all-α-N-terminal domain(NTD),a Pseudomonas putida homologous domain(PPD),and an all-β-C-terminal domain(CTD).MsmVg was highly expressed in mature female adults and enriched in the ovaries of 3-day-old female adults.Disruption of MsmVg by RNA interference did not change the expression of MsmVg,vitellogenin(MsVg)or the vitellogenin receptor(MsVgR)in fat bodies,but it inhibited their transcription in ovaries.Phenotype analysis showed that knockdown of MsmVg did not affect yolk deposition in ovaries,but impaired eggshell formation and led to a reduction in the reproductive capacity.Furthermore,knockdown of MsmVg significantly inhibited the expression of genes associated with eggshell formation(MsChP1-3 and MsFcP3C).Taken together,these data suggest that MsmVg plays an important role in female reproduction by affecting eggshell formation in M.separata,which provides a potential target for managing this insect pest.