Conditional fitness benefits of the Rickettsia bacterial symbiont in an insect pest

Abstract

Inherited bacterial symbionts are common in arthropods and can have strong effects on the biology of their hosts. These effects are often mediated by host ecology. The Rickettsia symbiont can provide strong fitness benefits to its insect host, Bemisia tabaci, under laboratory and field conditions. However, the frequency of the symbiont is heterogeneous among field collection sites across the USA, suggesting that the benefits of the symbiont are contingent on additional factors. In two whitefly genetic lines collected from the same location, we tested the effect of Rickettsia on whitefly survival after heat shock, on whitefly competitiveness at different temperatures, and on whitefly competitiveness at different starting frequencies of Rickettsia. Rickettsia did not provide protection against heat shock nor affect the competitiveness of whiteflies at different temperatures or starting frequencies. However, there was a strong interaction between Rickettsia infection and whitefly genetic line. Performance measures indicated that Rickettsia was associated with significant female bias in both whitefly genetic lines, but in the second whitefly genetic line it conferred no significant fitness benefits nor conferred any competitive advantage to its host over uninfected whiteflies in population cages. These results help to explain other reports of variation in the phenotype of the symbiosis. Furthermore, they demonstrate the complex nature of these close symbiotic associations and the need to consider these interactions in the context of host population structure.

Context‐dependent mutualisms in the Joshua tree–yucca moth system shift along a climate gradient

“…Our results suggest that the outcome of the Joshua tree-yucca moth mutualism varies with respect to its location on the elevation gradient, in agreement with other research that demonstrates context dependency in mutualistic interactions (Bronstein 1994, Chamberlain et al 2014, Cass et al 2016, Ji and Bever 2016, Tylianakis and Morris 2017. Specifically, the outcome of the mutualism (viable seed set) is congruent with optimum host vigor under current conditions, around the middle of the elevation range.…”

“…, Cass et al. , Ji and Bever , Tylianakis and Morris ). Specifically, the outcome of the mutualism (viable seed set) is congruent with optimum host vigor under current conditions, around the middle of the elevation range.…”

A snapshot of the microbiome of Amblyomma tuberculatum ticks infesting the gopher tortoise, an endangered species

“…The necessity of symbiont for nutritional supplemental has been described in many hematophagus arthropods including ticks (Rio et al, 2016). In an interesting study, Rickettsia -infected whiteflies developed high survival rates and faster, higher fecundity when compared to whiteflies lacking Rickettsia infection, suggesting the potential role of these endosymbionts in the survival in particular genetic line (Cass et al, 2016; Himler et al, 2011). …”

Effects of “Candidatus Liberibacter solanacearum” (haplotype B) on Bactericera cockerelli fitness and vitellogenesis

“…Other studies had reported the association of insects with bacteria inducing feminization. For example, in whiteflies (Bemisia tabaci), Rickettsia was found to be associated with a significant female bias in two whitefly genetic lines (Cass et al, 2016). Also, other members of the order Rickettsiales, such as Wolbachia, a diverse group of intracellular bacteria with different symbiotic relationships, induce diverse phenotypes in their insect hosts including female-bias, parthenogenetic induction, and cytoplasmic incompatibility (Werren et al, 2008).…”