Abstract – Metabolomics reveals target plant biochemistry may mediate biocontrol agent larval performance

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Abstract

One of the great conundrums associated with biological control of weeds occurs when some insects released as control agents fail to establish or achieve low population viability despite being reunited with a closely co-evolved host plant. Such failures are often attributed to mismatches either between the agent and its new environment (environmental resilience), environmental or climatic stochasticity, and/or the Allee effect and associated demographic stochasticity. All these factors can impose limitations or extinction on small populations. There is however a paucity of literature on other possible underlying mechanisms, including target plant biochemical defence systems, which might also impair insect biocontrol agent establishment while at low population densities. Understanding plant biochemical responses to insect herbivores can now be readily achieved using non-targeted metabolomics. Here we demonstrate the application of this technology to address questions about the biochemical responses of heather (Calluna vulgaris) to the biocontrol agent Lochmaea suturalis at varying larval population densities under field conditions. We demonstrate significant variation in growth between larvae grazing on undamaged vs. previously damaged heather which may also involve population density dependent factors. Understanding the biochemical complexity of target plant and control agent interactions, may provide information to design and tailor more effective release strategies. 

keywords 

Calluna vulgaris 

metabolomics 

biochemical response 

larval growth 

release strategies 

Highlights 

Metabolomic analysis reveals biochemical changes to heather, induced by control agent feeding 

Previously grazed heather maintained higher control agent population density and growth rates 

Phytochemical response to control agent grazing may provide information for release strategy design