A DNA barcode-based survey of terrestrial arthropods in the Society Islands of French Polynesia: host diversity within the SymbioCode Project

Thibault Ramage,Gladys Mialdea,Roland Allemand,Neil Davies,Anne Duplouy,Patricia Martins-Simoes,George K Roderick,Pascal Rousse,Sylvain Charlat

doi:10.5852/ejt.2017.272

Abstract

We report here on the taxonomic and molecular diversity of 10 929 terrestrial arthropod specimens, collected on four islands of the Society Archipelago, French Polynesia. The survey was part of the ‘SymbioCode Project’ that aims to establish the Society Islands as a natural laboratory in which to investigate the flux of bacterial symbionts (e.g., Wolbachia) and other genetic material among branches of the arthropod tree. The sample includes an estimated 1127 species, of which 1098 included at least one DNA-barcoded specimen and 29 were identified to species level using morphological traits only. Species counts based on molecular data emphasize that some groups have been understudied in this region and deserve more focused taxonomic effort, notably Diptera, Lepidoptera and Hymenoptera. Some taxa that were also subjected to morphological scrutiny reveal a consistent match between DNA and morphology-based species boundaries in 90% of the cases, with a larger than expected genetic diversity in the remaining 10%. Many species from this sample are new to this region or are undescribed. Some are under description, but many await inspection by motivated experts, who can use the online images or request access to ethanol-stored specimens.

Highlights

We report on the diversity of a large and non-taxonomically focused sample of terrestrial arthropods, collected on four islands of the Society Archipelago (French Polynesia) from 2005 to 2007
One fifth of the species present in this sample have been identified at the species level, extending the known range of some species to French Polynesia and enriching knowledge of other groups of taxa
The correlation between molecular-based OTUs and morphology-based species identity was assessed in 107 species that were distinguished on the basis of morphology and included at least two barcoded specimens

Summary

Introduction

We report on the diversity of a large and non-taxonomically focused sample of terrestrial arthropods, collected on four islands of the Society Archipelago (French Polynesia) from 2005 to 2007. This sample was obtained as part of the SymbioCode initiative (coordinated by SC) in collaboration with the Moorea Biocode Project (http://biocode.berkeley.edu) (Check 2006). This study focused on four of the five main islands of the Society, situated along a 200 km northwest/ southeast axis, corresponding to the movement of the Pacific plate over a unique hot spot during the last three million years (Guillou et al 2005). Much of the South Pacific’s terrestrial biota originates from the west (Australasia), colonizing the oceanic islands via stepping-stone dispersal (Miller 1996; Gillespie & Roderick 2002; Gressitt 1956)

Methods

Results

Conclusion