Figure 1.

Acquisition by aphids of particles of virus 1 (○) and virus 2 (●), interacting in a competitive way and manifesting spatial separation in the co‐infected host plant. Virions of spatially separated viruses 1 and 2 mix only within a thin border zone separating viral subpopulations in the host tissue. There they compete with one another for access to binding sites (bs) on the aphid's stylets (st). Consequently, spatial separation decreases the probability of the simultaneous acquisition and transmission of both viruses by individual aphids probing the plant tissue at the border zone.