Figure 1.

Estimates of symbiont incidence, x_0.001 (i.e. the proportion of species infected at a prevalence of greater than 1/1000) in terrestrial arthropods. Estimates obtained from (a) fitting a beta distribution to the complete database; (b) fitting a doubly inflated beta distribution to the complete database, and so allowing for completely uninfected or completely infected species; (c) standardized sampling (i.e. a weighted sum of estimates from the largest arthropod taxa, using the single largest population sample from each sampled species).