Sexual differences in transmission and accumulation of tomato spotted wilt virus in its insect vector Frankliniella occidentalis (Thysanoptera : Thripidae)

Sexual differences in the transmission and accumulation of tomato spotted wilt virus (TSWV) were investigated in adults of the western flower thrips, Frankliniella occidentalis. Both TSWV transmission rates to petunia leaf disks and the triple antibody sandwich enzyme-1inked immunosorbent assay (TAS-ELISA)-positive rates showed no significant difference between the sexes. In ELISA-positive thrips, however, males transmitted TSWV to leaf disks with a significantly higher efficiency than females : 81% in males and 47% in females. Apparently, TSWV-transmitters had higher ELISA values than non-transmitters, and the average ELISA value of female transmitters was approximately 2 times that of male transmitters. These results suggest that TSWV may have a higher propagation rate in females than in males, whereas the efficiency of the virus transmission by males may be greater than that by females if they become viruliferous adults. Potential causes for these differences are discussed.