Fizzing out:

Increasing CO2 levels diminish biocontrol of invasive tropical soda apple

Diaz, R., V. Manrique, Z. He, and W.A. Overholt. 2012. Effect of elevated CO2 on tropical soda apple and its biological control agent Gratiana boliviana (Coleoptera: Chrysomelidae). Biocontrol Science and Technology 22: 763-776 PDF.

Summary

Biological control agents can be used to manage some invasive plant populations, but climate change may threaten their continued effectiveness. This study investigated the effect of elevated CO2 levels on the performance of a plant invasive to the southeastern U.S., tropical soda apple (Solanum viarum), and the host-specific biocontrol beetle (Gratiana boliviana) used against it. Plants were grown and beetles were exposed to ambient, medium, and high levels of CO2, and metrics of performance were recorded. Under high levels of CO2, plants had greater biomass. In contrast, the biocontrol beetle had reduced survival, slower developmental time, smaller body size, and lower consumption of leaves by fifth instars. These results suggest decreased performance of G. boliviana in controlling a more aggressive tropical soda apple as CO2 levels in our atmosphere continue to rise.

Take home points

  • The effectiveness of biocontrol agents are expected to change under future climate conditions.

  • The invasive plant tropical soda apple (Solanum viarum) performed better and its biocontrol beetle (G. boliviana) performed worse under elevated CO2 levels.

  • The effectiveness of this biocontrol agent on tropical soda apple will be diminished as CO2 levels continue to increase.

Management implications

  • The effects of climate change should be added as a consideration when evaluating future biocontrol agents.

  • The timing, source populations, and frequency of biocontrol releases may need to be adjusted under future climate conditions.

  • Managers and researchers should collaborate to identify high priority biocontrol systems to study.

Read more about this topic: Lu et al. 2013, Sun et al. 2020

Keywords

Changing biotic interactions (competitiveness), Management efficacy, Impact studies, Solanum viarum, Gratiana boliviana, Biocontrol, Invasive plants