BACKGROUND: Tomato spotted wilt virus (TSWV), one of the most devastating viruses of ornamental plants and vegetable crops worldwide, is transmitted by the western flower thrips, Frankliniella occidentalis (Pergande), in a persistent-propagative manner. How TSWV manipulates the reproduction of its vector to enhance transmission and whether infection with TSWV changes the mating behaviour of this thrips vector are not fully understood. RESULTS:In this study, we found that TSWV-exposed thrips, in general, had a significantly longer developmental time than did non-exposed individuals. Such an increase was predominantly seen in adults, a stage associated with dispersal and virus transmission. TSWV-exposed F. occidentalis produced substantially more progeny than did non-exposed thrips. Interestingly, most of the increase in progeny came from an increase in males, a sex with a greater dispersal and virus transmission capability. Specifically, the sex ratio of progeny shifted from female biased (2-7:1) to evenly split or male biased. Regarding mating behaviour, compared to virus-free controls, TSWV-exposed F. occidentalis had significantly longer copulation duration, were more active in males, and remated less often in females. CONCLUSION: These combined results suggest that TSWV alters the reproductive behaviour of its insect vector, F. occidentalis, to promote virus transmission. Consequently, a monitoring program capable of earlier detection of the virus and a reduced economic threshold for vector (thrips) control should be in consideration for the long-term, sustainable management of TSWV.

The current pneumonia epidemic in China could evolve into a pandemic on a global scale if not effectively contained. The 2019-nCoV possesses a 61-amino acid open reading frame resembling SARS-CoV virulence factor - ORF6 peptide. The isoleucine content is 15.9% in ORF6 of SARS-CoV versus 16.4% of that in 2019-nCoV. Given the proton affinity in the carbonyl oxygen in isoleucine, augmented proton traffic can enhance proton-ion antiport and prompt cell swelling. As the content of essential amino acids in the open reading frame of 2019-nCoV reaches 57.4%, a starch/vitamin diet served for short period of time does not give rise to essential amino acids and halts virion production, which could be adopted as prophylactic approach of many viral infections. Plant-based diet or fasting/boiled rice water can also minimize the intake of essential amino acids or all amino acids respectively. Calorie restriction has been confirmed in animal studies to extend lifespan, and its underlying mechanism is not fully known. Furthermore, several proteins of 2019-nCoV possess high valine plus glycine content, which is implicated in heart disease.