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Still a host of hosts for Wolbachia: analysis of recent data suggests that 40% of terrestrial arthropod species are infected.

Zug R, Hammerstein P - PLoS ONE (2012)

Bottom Line: At the same time, the authors of this analysis highlighted some weaknesses of the underlying data and concluded that in order to improve the estimate, a larger number of individuals per species should be assayed and species be chosen more randomly.Notwithstanding this difference, we confirm the previous result that, within a given species, typically most or only a few individuals are infected.For these symbionts we find a large variation in estimated infection frequencies and corroborate the finding that Wolbachia are the most abundant endosymbionts among arthropod species.

View Article: PubMed Central - PubMed

Affiliation: Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany. roman.zug@biologie.hu-berlin.de

ABSTRACT
Wolbachia are intracellular bacteria that manipulate the reproduction of their arthropod hosts in remarkable ways. They are predominantly transmitted vertically from mother to offspring but also occasionally horizontally between species. In doing so, they infect a huge range of arthropod species worldwide. Recently, a statistical analysis estimated the infection frequency of Wolbachia among arthropod hosts to be 66%. At the same time, the authors of this analysis highlighted some weaknesses of the underlying data and concluded that in order to improve the estimate, a larger number of individuals per species should be assayed and species be chosen more randomly. Here we apply the statistical approach to a more appropriate data set from a recent survey that tested both a broad range of species and a sufficient number of individuals per species. Indeed, we find a substantially different infection frequency: We now estimate the proportion of Wolbachia-infected species to be around 40% which is lower than the previous estimate but still points to a surprisingly high number of arthropods harboring the bacteria. Notwithstanding this difference, we confirm the previous result that, within a given species, typically most or only a few individuals are infected. Moreover, we extend our analysis to include several reproductive parasites other than Wolbachia that were also screened for in the aforementioned empirical survey. For these symbionts we find a large variation in estimated infection frequencies and corroborate the finding that Wolbachia are the most abundant endosymbionts among arthropod species.

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Estimated probability distribution of Wolbachia prevalence.
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pone-0038544-g001: Estimated probability distribution of Wolbachia prevalence.

Mentions: The prevalence distribution for Wolbachia shows that either most or only few individuals within a species are infected (Figure 1). Based on this distribution, Wolbachia incidence is estimated to be x = 0.406 for c = 0.001 (Table 1). We chose c = 0.001 in accordance with Hilgenboecker et al. [2] to facilitate comparisons. Our results confirm the main qualitative findings from the previous meta-analysis, i.e. the ‘most-or-few’ prevalence pattern and the likely underestimation of incidence in previous Wolbachia screenings. However, there is one major difference between the results of the two analyses: In the first study, Wolbachia incidence was estimated to be 66% (for c = 0.001). Based on the data from Duron et al. [5], we now obtain a lower estimate of the percentage of Wolbachia-infected species, i.e. approximately 40%. We think that our current estimate is more reasonable for the following three reasons.


Still a host of hosts for Wolbachia: analysis of recent data suggests that 40% of terrestrial arthropod species are infected.

Zug R, Hammerstein P - PLoS ONE (2012)

Estimated probability distribution of Wolbachia prevalence.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369835&req=5

pone-0038544-g001: Estimated probability distribution of Wolbachia prevalence.
Mentions: The prevalence distribution for Wolbachia shows that either most or only few individuals within a species are infected (Figure 1). Based on this distribution, Wolbachia incidence is estimated to be x = 0.406 for c = 0.001 (Table 1). We chose c = 0.001 in accordance with Hilgenboecker et al. [2] to facilitate comparisons. Our results confirm the main qualitative findings from the previous meta-analysis, i.e. the ‘most-or-few’ prevalence pattern and the likely underestimation of incidence in previous Wolbachia screenings. However, there is one major difference between the results of the two analyses: In the first study, Wolbachia incidence was estimated to be 66% (for c = 0.001). Based on the data from Duron et al. [5], we now obtain a lower estimate of the percentage of Wolbachia-infected species, i.e. approximately 40%. We think that our current estimate is more reasonable for the following three reasons.

Bottom Line: At the same time, the authors of this analysis highlighted some weaknesses of the underlying data and concluded that in order to improve the estimate, a larger number of individuals per species should be assayed and species be chosen more randomly.Notwithstanding this difference, we confirm the previous result that, within a given species, typically most or only a few individuals are infected.For these symbionts we find a large variation in estimated infection frequencies and corroborate the finding that Wolbachia are the most abundant endosymbionts among arthropod species.

View Article: PubMed Central - PubMed

Affiliation: Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany. roman.zug@biologie.hu-berlin.de

ABSTRACT
Wolbachia are intracellular bacteria that manipulate the reproduction of their arthropod hosts in remarkable ways. They are predominantly transmitted vertically from mother to offspring but also occasionally horizontally between species. In doing so, they infect a huge range of arthropod species worldwide. Recently, a statistical analysis estimated the infection frequency of Wolbachia among arthropod hosts to be 66%. At the same time, the authors of this analysis highlighted some weaknesses of the underlying data and concluded that in order to improve the estimate, a larger number of individuals per species should be assayed and species be chosen more randomly. Here we apply the statistical approach to a more appropriate data set from a recent survey that tested both a broad range of species and a sufficient number of individuals per species. Indeed, we find a substantially different infection frequency: We now estimate the proportion of Wolbachia-infected species to be around 40% which is lower than the previous estimate but still points to a surprisingly high number of arthropods harboring the bacteria. Notwithstanding this difference, we confirm the previous result that, within a given species, typically most or only a few individuals are infected. Moreover, we extend our analysis to include several reproductive parasites other than Wolbachia that were also screened for in the aforementioned empirical survey. For these symbionts we find a large variation in estimated infection frequencies and corroborate the finding that Wolbachia are the most abundant endosymbionts among arthropod species.

Show MeSH
Related in: MedlinePlus