Cryptic Species Composition And Dispersal Routes Of Eupristina Verticillata

Biological invasion has become a main threat to biodiversity and social economy around the world.It is therefore of great necessity to unravel the mechanisms underlying the successful invasion of alien species for guiding the design of relevant strategies to prevent and control biological invasions.For the alien species with mutualistic symbionts,whether their symbionts can arrive determines their invasion risks.Thus,it is crucial to describe the species composition and the dispersal routes of the symbiotic species associated with invasive species.In this study,we focused on the specific pollinating wasps(the morphological species: Eupristina verticillata)of Ficus microcarpa.The native range of this plant species covers the south part of China and the north part of Australia,and it has been introduced into many parts of world and become invasive in North America,South America and the Mediterranean region right after the colonization of E.verticillata.To explore the cryptic species composition and dispersal routes of E.verticillata,we identified SNP markers for the sampled pollinator individuals from 22 sites using the whole genome resequencing technique,combined with the genetic variations in a mitochondrial gene(COI)in some sampled individuals.The main results are as follows:(1)We sequenced the genomes of 130 sampled individuals and obtained a total of1440.67 G clean data after quality control and filtering.We then mapping clean data to the published genome of E.verticillata,and found very low mapping ratios in 32 individuals that were excluded from further analysis and that the rest 98 individuals from 19 sites with a total of 634,708 annotated SNPs were used in population genomics.(2)Using the genetic variation information from both COI gene and nuclear genome,the results of clustering analysis and phylogenetic analysis showed that there were three cryptic species within E.verticillata.One only distributed in two native sites of F.microcarpa(Brisbane and Xishuangbanna),and one was only detected in Thailand sites(containing most of the 32 sampled individuals excluded from population genomic analysis due to low mapping ratios),and the other was the dominant cryptic species with a wide distribution in all native and introduced sites of F.macrocarpa except Brisbane and Thailand sites.(3)We then conducted clustering analysis for the only cryptic species colonizing the introduced sites of F.microcarpa far from its native range,and found that all populations in the introduced range belonged to two genetic groups which only existed in the Philippines in the plant's native range.This suggests that the immigration of the species might originate from the Philippines.The results of population genetic structure and genetic diversity analysis showed that it first migrated from the Philippines to the USA,followed by the colonization of Brazil and Greek islands,with frequent gene flow among populations in the Mediterranean region(Nm values from 1.8158 to 3.1028)likely forming a meta-population.Our results revealed the cryptic species composition and the dispersal routes of E.verticillata,showing a possible mechanism causing the invasion of F.microcarpa and providing insights into the prevention and the control of the invasive species relying on mutualistic symbionts.