Color morph and infection with Candidatus Liberibacter asiaticus influence flight capability and dispersal of the Asian citrus psyllid

In the context of a vector-borne pathogen system, the spread of disease depends on movement of vectors across a landscape.  We examined the flight capability of the Asian citrus psyllid (Diphorina citri Kuwayama, Hemiptera: Liviidae) with a laboratory flight mill. D. citri is the vector of the bacterial pathogen Candidatus Liberibacter asiaticus (CLas) potentially causing huanglongbing or citrus greening disease. Initially, we compared the flight capability of D. citri depending on their sex and morphotype (color of abdomen). Two general morphotypes exist within this species: green/blue and gray/brown. We observed that approximately 32% of psyllids from the green/blue morphotype tested exhibited long durations of flight (> 60 s); whereas; less than 5% of psyllids from the gray/brown morphotype performed such long duration flights. There was no difference in flight performance between the two sexes within both the gray/brown and green/blue morphotypes. We measured pronotum width and wing length. However, neither pronotum, nor wing size, were associated with flight capability of D. citri. Subsequently, we tested if psyllids infected with the plant pathogen, CLas, were more prone to flight than uninfected psyllids. We observed that 57% of the green/blue psyllids infected with CLas performed long durations of flight, while only 30% of uninfected psyllids performed such long duration flights. Finally, we performed a third experiment where psyllids were allowed to settle on plants for three days, and subsequently allowed to disperse to a newly introduced plant during the next four days. In this case, we observed that CLas-infected psyllids were more prone to disperse than uninfected psyllids. Greater propensity for dispersal by psyllids infected with CLas than uninfected counterparts may indicate host-phenotype manipulation by the pathogen. By increasing dispersal of its vector, the pathogen may be manipulating vector behavior to increase its own proliferation.