Abstract Most plant viruses depend upon arthropod vectors for their transmission among plant hosts. There are shreds of evidence of insect vectors and host manipulations by plant viruses for facilitating virus transmission. Fig mosaic disease is a globally distributed viral plant disease for which only fig mosaic virus (FMV) has been identified as the causal agent. In this study, we investigated the effect of FMV on the fitness of its mite vector using an age-stage two-sex life table approach, which provided detailed life stage durations of each nymph and adult (both sexes). To do this, the life history traits of the FMV-viruliferous (V) and non-viruliferous (NV) mite colonies on the healthy fig leaves and FMV-viruliferous mites on FMV-infected fig leaves (VL) were analyzed. Seventy pairs of adult mites from each colony (same age) were released on uninfected and infected fig leaves in a Petri dish, and placed in a growth chamber at 28 ± 2 °C and 12:12 (L: D) photoperiod. Our results showed that the non-viruliferous mites survived longer, produced higher number of offspring, and showed less mortality, while the viruliferous mites completed their pre-adult development faster than the non-viruliferous mites. Despite these differences, there were no significant differences in the population growth parameters of the viruliferous mites compared to the non-viruliferous mites. This suggests that FMV may exert subtle fitness trade-offs on its vector, balancing potential fitness costs to ensure successful transmission.
Daneshnia et al. (Mon,) studied this question.