A comparison of microbiota in the ladybird Harmonia axyridis between native and invaded ranges

As a biocontrol agent of aphids and coccids, the harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), was introduced from its native Asian range into North America. There, it has spread quickly and widely, potentially contributing to the decline of endemic ladybirds. This study examined microbial communities residing in H. axyridis in its native and introduced or invaded regions. We collected ladybirds at 11 localities across mainland China (native range) and at seven localities across the USA (invaded range) and applied next-generation amplicon sequencing to examine microbial communities. We found that the diversity of the microbial community of H. axyridis in the invaded range declined compared to the native range. The microbial community differed markedly in composition between native and invaded ranges. Among all identified 22047 amplicon sequence variants, only 4.2% were shared by the two ranges, whereas 4967 were unique to the invaded and 16159 to the native range. Our findings suggest that the composition of the microbial community of H. axyridis is largely restructured in the invaded North American region compared to the native Asian region.