Detecting host-parasitoid interactions in an invasive Lepidopteran using nested tagging DNA-metabarcoding

Abstract

Determining the host-parasitoid interactions and parasitism rates for invasive species entering novel environments is an important first step in assessing potential routes for biocontrol and integrated pest management. Conventional insect rearing techniques followed by taxonomic identification are widely used to obtain such data, but this can be time consuming and prone to biases. Here we present a Next Generation Sequencing approach for use in ecological studies which allows for individual level metadata tracking of large numbers of invertebrate samples through the use of hierarchically organised molecular identification tags. We demonstrate its utility using a sample data set examining both species identity and levels of parasitism in late larval stages of the Oak Processionary Moth (Thaumetopoea processionea -Linn. 1758), an invasive species recently established in the UK. Overall we find that there are two main species exploiting the late larval stages of Oak Processionary Moth in the UK with the main parasitoid (Carcelia iliaca -Ratzeburg, 1840) parasitising 45.7% of caterpillars, while a rare secondary parasitoid (Compsilura conccinata -Meigen, 1824) was also detected in 0.4% of caterpillars. Using this approach on all life stages of the Oak Processionary Moth may demonstrate additional parasitoid diversity. We discuss the wider potential of nested tagging DNAmetabarcoding for constructing large, highly-resolved species interaction networks.

Mechanisms structuring host–parasitoid networks in a global warming context: a review

“…Finally, ecological entomologists will need to capitalise on the availability of new molecular methods, such as DNA metabarcoding, as well as proven methods like multiplex PCR, to study complex ecological networks (Hrček & Godfray, 2015;Evans et al, 2016;Ye et al, 2017;Derocles et al, 2018;Kitson et al, 2018). Such approaches can reveal new host-parasitoid associations in complex communities (Condon et al, 2014) and are also vital to identify facultative endosymbionts -and hence their effects -within these networks.…”

Introduction: Special issue on species interactions, ecological networks and community dynamics – Untangling the entangled bank using molecular techniques

“…In terms of the types of interactions addressed, this Special Issue shows how molecular techniques can be applied to resolving mutualistic interactions such as pollen transport (Bell et al, ; Tiusanen et al, ) and seed dispersal (González‐Varo et al, ), antagonistic interactions including predator–prey interactions (Deagle et al, ; Eitzinger et al, ; Mata et al, ; Sint, Kaufmann, Mayer, & Traugott, ; Verschut, Strandmark, Esparza‐Salas, & Hambäck Walters et al, ), predator–prey‐and‐detritus interactions (Siegenthaler, Wangensteen, Benvenuto, Campos, & Mariani, ), host–parasitoid interactions (Gariepy et al, ; Kitson et al, ), host–symbiont interactions (Doña, Proctor, et al, ; Doña, Serrano, Mironov, Montesinos‐Navarro, & Jovani, ), plant–herbivore interactions (Bhattacharyya, Dawson, Hipperson, & Ishtiaq, ), plant–fungus interactions (Schröter et al, ; Sepp et al, ), plant–prey interactions (Littlefair, Zander, de Sena Costa, & Clare, ), fungus–fungivore interactions (Koskinen et al, ) and multifaceted interactions (Clare et al, ).…”

“…Emphasizing the message from previous reviews (from Symondson & Harwood, to Roslin & Majaneva, ), the featured case studies also reveal just how much power molecular tools add by resolving “hidden” and hard‐to‐observe ecological interactions (Wirta et al, ). By allowing us to pinpoint associations between organisms which liquefy their prey (Eitzinger et al, ; Littlefair et al, ; Sint et al, ; Verschut, Strandmark, Esparza‐Salas, & Hambäck ), hide within their hosts (Gariepy et al, ; Kitson et al, ), lack all diagnostic characters as larvae (Gariepy et al, ; Kitson et al, ; Koskinen et al, ), hunt at night (Mata et al, ) or are simply too small and similar to describe by any other means (Jones & Hallin, ; Walters et al, ), they reveal new aspects of community organization. Importantly, this is not a question of adding fine nuance to main colour, but of repainting the whole picture.…”

“…Kitson et al () use nested‐tagging DNA metabarcoding for exploring the parasitoid community of the oak processionary moth ( Thaumetopoea processionea ), an invasive species recently established in the UK. Overall, they are able to identify the main parasitoid of the late larval stages of T. processionea as Carcelia iliaca —at the same time creating the tools for describing all life stages of the oak processionary moth and the tag set needed to process massive ecological samples at the individual level.…”

Scaling up DNA metabarcoding for freshwater macrozoobenthos monitoring

“…Alternative approaches that add tagging to the first PCR step could be considered as well (Kitson et al, 2018). However, any tagging approach should be carefully chosen and experimentally evaluated.…”