Homogenized Phylogeographic Structure across the Indo-Burma Ranges of a Large Monoecious Fig, Ficus altissima Blume

Abstract

As well as bountiful natural resources, the Indo-Burma biodiversity hotspot features high rates of habitat destruction and fragmentation due to increasing human activity; however, most of the Indo-Burma species are poorly studied. The exploration of plants closely associated with human activity will further assist us to understand our influence in the context of the ongoing extinction events in the Anthropocene. This study, based on widely and intensively sampled F. altissima across Indo-Burma and the adjacent south China ranges, using both the chloroplast psbA-trnH spacer and sixteen newly developed nuclear microsatellite markers (nSSRs), aims to explore its spatial genetic structure. The results indicated low chloroplast haplotype diversity and a moderate level of nuclear genetic diversity. Although limited seed flow was revealed by psbA-trnH, no discernible phylogeographic structure was shown due to the low resolution of cpDNA markers and dominance of an ancestral haplotype. From the nSSRs data set, phylogeographic structure was homogenized, most likely due to extensive pollen flow mediated by pollinating fig wasps. Additionally, human cultivation and human-mediated transplanting further confounded the analyses of population structure. No geographic barriers are evident across the large study range, with F. altissima constituting a single population, and extensive human cultivation is likely to have had beneficial consequences for protecting the genetic diversity of F. altissima.

Can pollinators track plant expansions? A case study on the genetic structure of a host‐dependent pollinating wasp

“…This differs with yucca moth ( Tegeticula yuccasella ), which revealed no significant genetic structure between populations sampled in the native and planted host ranges (Leebens‐Mack & Pellmyr, 2004). However, similar result was found in the host plant F. altissima at its planted range (Huang et al, 2021). This finding suggested that similar genetic structuring may be achieved in obligate mutualisms at their expansion ranges despite a different introduction history.…”

“…Furthermore, large gene flow in E. altissima is supported by a relatively low level of differentiation among native populations and no distinct genetic structure among populations revealed by STRUCTURE (Figure 4, Figure 5c). Missing phylogeographic structure of F. altissima across Indo‐Burma and south China again supports the long‐distance dispersal of E. altissima (Huang et al, 2021). Those characters together suggest that long‐distance dispersal of E. altissima facilitates it tracking the host's artificial range expansion.…”

“…Given fig wasps' long‐distance dispersal ability and E. altissima 's specific relationship to F . altissima (Huang et al, 2021), we hypothesized that the pollinator ( E. altissima ) can track its host's rapid range expansion, and that decreased genetic diversity will be observed in introduced populations at higher latitudes due to serial founding events. Specifically, we try to answer the following questions: (1) Are the pollinating wasps of planted F. altissima populations dispersed from their native range or shifted from related local fig species?…”

“…In order to address the above questions, we collected fig wasps from figs of F. altissima (a monoecious species with human-mediated rapid range expansion to higher latitudes) in both native and introduced ranges, and identified the pollinators (Eupristina altissima) using molecular markers. Given fig wasps' long-distance dispersal ability and E. altissima's specific relationship to F. altissima (Huang et al, 2021), we hypothesized that the pollinator (E. altissima) can track its host's rapid range expansion, and that decreased genetic diversity will be observed in introduced populations at higher latitudes due to serial founding events. Specifically, we try to answer the following ques-…”

High genetic diversity and low population differentiation of a medical plant Ficus hirta Vahl., uncovered by microsatellite loci: implications for conservation and breeding

“…In addition, fruit-eating animals like birds, monkeys and bats etc. also play a role in fig seed dispersal [ 34 , 35 ]. Meanwhile, according to our observations, the large effective population size and relatively continuous distribution of F. hirta may further prevent the loss of novel alleles, and consequently maintain the gene flow and genetic diversity.…”