The interaction term was not significant, so we then fitted a model using only the main fixed and random effects. The Intercept of the random effect contributed no variance to the model, so we then fitted a model with fixed effects only. We also used Pearson correlation to test the hypothesis that there would be a positive correlation between the number of studies for bacteria, fungi, nematodes and viruses and the number of microbes or nematodes observed in the native and introduced range. Wasps used here were those collected for a separate study on the population genetics of TWS119 GSK-3 inhibitor common wasps in their native and invaded range. Twenty individual wasps were taken from each of two ABT-199 in vivo countries in the invaded range, and from each of two countries within the native range where invasive populations appear likely to have originated. The samples of foraging workers or workers from nests were preserved in 90% ethanol prior to being sent to New Zealand, or were frozen immediately. When wasps were taken from nests, only one worker from each nest was used. Wasp samples were in storage < 12 months when used for this analysis. In Belgium, New Zealand, and the United Kingdom the wasps sampling did not require governmental or local authority permission. Wasps in Argentina were collected under permit 1233 from the Administracion de Parques Nacionales. Twenty separate sampling locations were used for Belgium, New Zealand, and the United Kingdom. Only 13 sites were sampled from Argentina, so two wasps were used from the same site in some locations. We observed no evidence to support the enemy release hypothesis, at least in terms of the total number of microorganism taxa observed in the introduced range compared to the native range. Wasps in the introduced range had a similar prevalence of pathogen and microbial species compared to the samples from the native range, both in the historical and proteomics datasets. The pathogens observed through the proteomics methods were often identified as also pathogens of honey bee or other hymenoptera. While the total number of microbial taxa was similar between native and invaded ranges, a degree of distinctiveness was observed. Between nine and 14 taxa were unique to each country. While this could represent a sampling effect, it could also indicate that some pathogens or microbial taxa key to the density-dependent population regulation of wasps are missing from the invaded range. Different pathogens vary considerably in their virulence and perhaps taxa with high virulence are absent from the invaded range. The absence of key enemies in the invaded species seems possible given the considerable fluctuation observed in population densities of wasps in countries like England, with no evidence of similar variation in abundance in the invaded range.