Genetic diversity of the two-spotted stink bug Bathycoelia distincta (Pentatomidae) associated with macadamia orchards in South Africa

PLoS One. 2022 Jun 10;17(6):e0269373. doi: 10.1371/journal.pone.0269373. eCollection 2022.

Abstract

The South African macadamia industry is severely affected by a complex of stink bugs, dominated by the two-spotted stink bug, Bathycoelia distincta Distant (Pentatomidae). This species was first discovered during the spring of 1984 in the Limpopo province. Although considerable effort has been spent trying to manage this pest, it continues to be a pest of concern for the macadamia industry. Information on the genetic diversity of this species is lacking, despite the potential relevance of such information for management strategies. The present study aimed to characterise the genetic diversity of B. distincta populations in South Africa. The Cytochrome c Oxidase Subunit 1 (COI) and cytochrome b (Cytb) gene regions were sequenced from individuals collected from the three main regions of macadamia production over three different seasons (2018-2020). An overall high haplotype diversity (COI = 0.744, Cytb = 0.549 and COI+Cytb = 0.875) was observed. Pairwise mean genetic distance between populations from each region varied from 0.2-0.4% in both datasets, which suggests the absence of cryptic species. The median joining network for both datasets consisted of one or two central haplotypes shared between the regions in addition to unique haplotypes observed in each region. Finally, low genetic differentiation (FST < 0.1), high gene flow (Nm > 1) and the absence of a correlation between genetic and geographic distance were estimated among populations. Overall, these results suggest that the B. distincta populations are not structured among the areas of macadamia production in South Africa. This might be due to its ability to feed and reproduce on various plants and its high dispersal (airborne) between the different growing regions of the country along with the rapid expansion of macadamia plantations in South Africa.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Genetic Variation
  • Heteroptera*
  • Humans
  • Macadamia
  • Moths*
  • South Africa

Grants and funding

We would like to acknowledge the University of Pretoria, the Forestry and Agricultural Biotechnology Institute (FABI), the Centre for Excellence in Plant Biotechnology (CPHB), Macadamia South Africa NPC (SAMAC) and NRF Thuthuka for financial support. There was no additional external funding received for this study.