How many hosts? Modelling host breadth from field samples

Abstract

Summary 1. Host‐specificity is important in fundamental and applied studies of biodiversity, but it is difficult to generate definitive data for many species. 2. Here, we present a model framework for estimating the realized host breadth of dependent fauna from samples collected from replicate host individuals. We use Bayesian, Zero‐inflated Poisson regression to model the abundance conditional upon host use – our focal parameter. We illustrate the model using a data set of insects on threatened and non‐threatened plant species from eastern Australia. Estimating co‐extinction risk through threats to host organisms is a key application for the model, requiring assessment of the host‐specifici..