Comment on "Invasive harlequin ladybird carries biological weapons against native competitors".

Conclusions about the nontarget effects of putatively invasive pathogens should be based on biologically relevant data. We disagree that the research experiments on a microsporidium isolated from Harmonia axyridis conducted by Vilcinskas et al. (Reports, 17 May 2013, p. 862) can explain the decline of native coccinellid species in the absence of such data.