Characterisation of a nucleopolyhedrovirus and Spiroplasma sp. bacterium associated with outbreaking populations of the Antler moth Cerapteryx graminis

► Field populations of Cerapteryx graminis were sampled for associated microbes. ► A nucleopolyhedrovirus was characterised as a Group II alpha-baculovirus. Collected C. graminis populations had female-skewed sex-ratios. ► A Spiroplasma bacterium was widespread, possibly a male-killing phenotype