Leafhopper (Homoptera : Cicadellidae) transmission of aster yellows phytoplasma: Does gender matter?

Male and female aster leafhoppers, Macrosteles quadrilineatus Forbes, diffe r in their ability to transmit the aster yellows phytoplasma. In laboratory and greenhouse experiments, males were up to twice as likely as females to acquire and become infected with aster yellows phytoplasma as measured by polymerase chain reaction analysis. Yet, in 3 different experimental arenas , infected females were significantly more likely than infected males to tr ansmit aster yellows phytoplasma. When confined on single leaves, more fema les (55%) than males (35%) transmitted phytoplasma to lettuce plants. In ca ges with access to 4 lettuce plants, females transmitted to 18% and males t o 8% of the plants. When leafhoppers were released in the greenhouse, where leafhoppers were relatively unrestricted in their movement, females transm itted to 29.8% and males to 10.1% of lettuce plants. The pattern of spread by females in the greenhouse was significantly more clustered than that by males. The different movement and feeding behaviors of males and females ma y explain, in part, differences observed. We conclude that gender does matt er in transmission of aster yellows phytoplasma by the aster leafhopper.