Ecological Factors Associated with the Distribution of Cryptic Species and Their Facultative Endosymbionts.

The sweetpotato whitefly, species complex, comprises at least 44 morphologically indistinguishable cryptic species, whose endosymbiont infection patterns often varied at the spatial and temporal dimension. However, the effects of ecological factors (e.g., climatic or geographical factors) on the distribution of whitefly and the infection frequencies of their endosymbionts have not been fully elucidated. We, here, analyzed the associations between ecological factors and the distribution of whitefly and their three facultative endosymbionts (Candidatus , Candidatus , and sp.) by screening 665 individuals collected from 29 geographical localities across China. The study identified eight species via mitochondrial cytochrome oxidase I (mt) gene sequence alignment: two invasive species, MED (66.9%) and MEAM1 (12.2%), and six native cryptic species (20.9%), which differed in distribution patterns, ecological niches, and high suitability areas. The infection frequencies of the three endosymbionts in different cryptic species were distinct and multiple infections were relatively common in MED populations. Furthermore, the annual mean temperature positively affected sp. and sp. infection frequencies in MED but negatively affected the quantitative distribution of MED, which indicates that sp. and sp. maybe play a crucial role in the thermotolerance of MED, although the host whitefly per se exhibits no resistance to high temperature. Our findings revealed the complex effects of ecological factors on the expansion of the invasive whitefly.