Background: Mites represent the second largest group with diverse niches and feeding habits, except for insects. Scabies mites are the causative agents of highly contagious skin disease in humans and more than 100 mammals. Although several versions of Sarcoptes scabiei genome have been published, i.e. var. suis, var. canis and var. hominis, the chromosome-level genome and population divergence is still desired for the community. Besides, the molecular mechanisms that scabies mites adapt to a parasitic lifestyle remains unclear. The taxonomy and ancestral origin of the scabies mite is unknown. Results: Here, we reported the first chromosome-level reference genome of S. scabiei, which was isolated from rabbits. The genome has a contig N50 size of 5.92 Mb, a total assembled length of 57.30 Mb, and ~12.65% of repetitive sequences and 9,333 protein‑coding genes were predicted. Population genetics analysis supported that scabies mites isolated from different hosts can be subdivided by hosts, and humans are likely the primary hosts of scabies mites, followed by pigs, dogs, and rabbits. However, phylogeny results suggested that rabbit was infected with scabies long before they were domesticated by humans, contradicting previous hypothesis that humans transmitted scabies mites to animals through domestication. Comparative genomics between scabies mites and mites of other feeding habits provided clues concerning the mechanisms of adaptation to permanent parasitic life from morphology, detoxification, and metabolism. Conclusions: Together, the first chromosome-level S. scabiei genome and population genetics analysis indicated its genetic subdivisions and within-host species divergence, which also provide evidence for further control of this highly contagious skin disease.

Pine wilt disease (PWD), Bursaphelenchus xylophilus, is an extremely threatening invasion forest disease throughout the world, especially in Asia. B. xylophilus is spread in Asia by vector beetles of Monochamus alternatus, which has long no effective control method. Understanding of landscape effects on the dispersal and outbreaks of forest pests is crucial to establishing effective ecological control strategies. Here, we analyzed the samples of M. alternatus collected at landscapes in order to estimate the effects of landscape types on the genetic structure and dispersal of M. alternatus. The landscapes included the geographical scales, forest types and land uses. The individuals of M. alternatus were genotyped by using whole-genome resequencing. Population genetic structures were clearly differentiated at the intermediate scale, suggesting the intermediate scale is an effective barrier against natural dispersal of M. alternatus. We used the least-coat distances, least-cost transect analysis, and distance-based redundancy analysis to estimate the effects of forest types and land uses within the fine scales. The results showed that the gene flow and genetic diversity were positively correlated with host and mixed forests, whereas negatively with non-host forests. Among land-use landscapes, the roads had the positive effect on gene flow and genetic diversity but farmland and urban uses had negative effects. This highlights that human-mediated transport via roads was likely to be the main factor leading to the long-distance invasion of M. alternatus, whereas non-host landscapes could suppress the spread of this species. These findings may be useful to control the PWD dispersed by M. alternatus.