Factors in low transmissibility of Tomato spotted wilt virus (TSWV) in asexual onion thrips, Thrips tabaci (Thysanoptera: Thripidae): effects of virus infection on longevity of thrips vector
Inoue T1, Sakurai T2
1United Graduate School of Agricultural Sciences, Iwate University, Morioka 020-8550, Japan
2Department of Biology and Environmental Sciences, National Agricultural Research Center for Tohoku Region, Morioka 020-0198, Japan.
Correspondence: tsakurai@affrc.go.jp
Vector competence should be considered as the total transmission frequency during the potential transmission period from the onset of transmission to the vector death rather than the transmission rate for a certain period. The potential transmission period would be affected by vector longevity. If tospovirus infection has a negative effect on its vector longevity, the potential transmission period would shorten. In order to clarify the impact of infection of Tomato spotted wilt virus (TSWV) on the survival of two asexual Thrips tabaci populations, we compared i) the developmental rate, ii) the mortality before adult emergence and iii) the mortality during adult stage between virus exposed and non-exposed cohorts which were treated at young larval stage. No significant effects were observed in thrips developmental rate and the mortality rate during the developmental stage. However, the mortality trajectory showed that the age-specific mortality during adult stage was higher in virus exposed cohort than in non-exposed. We also estimated the potential transmission period from the mortality data and obtained the period of average 3.3 days in two tested populations. These results suggest that the potential transmission period shortened by TSWV infection may lead to low transmissibility of TSWV in asexual T. tabaci population.
