Plant choice for oviposition in the phytophagous insect Bemisia tabaci: cytotype, including symbionts, knows best

Most phytophagous insects harbour symbiotic microorganisms that may facilitate, at multiple levels, the exploitation of plants. Little is known, however, about the role of these symbionts in insects' host plant choice. The whitefly Bemisia tabaci is a good model to explore these topics. It harbours a nutritional ‘primary’ endosymbiont allowing it to thrive on plant sap, and up to seven ‘secondary’ endosymbionts (S-symbionts) whose roles in plant utilization are currently under study. Here, we first investigated the influence of cytotype on females' oviposition rate on hibiscus and lantana, a favourable and an unfavourable host plant, respectively, for B. tabaci. We then addressed whether cytotype affects whiteflies' plant choice for oviposition. Using genetically homogeneous whiteflies harbouring different cytotypes, we showed that oviposition rate was significantly lower on lantana than on hibiscus, but that this reduction varied between cytotypes. Moreover, according to their cytotype, whiteflies preferred hibiscus over lantana, or showed no preference. Thus, cytotype influenced plant choice for oviposition. Together, our results indicate that, without a cytotype that facilitates the utilization of lantana, whiteflies may avoid this host plant. Since cytotypes harbour different combinations of S-symbionts, we argue that these symbionts are very likely to influence whitefly oviposition behaviour. •Cytotype (including symbionts) affects whiteflies' oviposition rate.•Cytotype determines plant choice for oviposition.•Different symbiont combinations affect whitefly oviposition behaviour.