Elevated Atmospheric CO2 Impairs Aphid Escape Responses to Predators and Conspecific Alarm Signals
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Research into the impact of atmospheric change on predator–prey interactions has mainly focused on density dependent responses and trophic linkages. As yet, the chemical ecology underpinning predator–prey interactions has received little attention in environmental change research. Group living animals have evolved behavioral mechanisms to escape predation, including chemical alarm signalling. Chemical alarm signalling between conspecific prey could be susceptible to environmental change if the physiology and behavior of these organisms are affected by changes in dietary quality resulting from environmental change. Using Rubus idaeus plants, we show that elevated concentrations of atmospheric CO2 (eCO2) severely impaired escape responses of the aphid Amphorophora idaei to predation by ladybird larvae (Harmonia axyridis). Escape responses to ladybirds was reduced by >50 % after aphids had been reared on plants grown under eCO2. This behavioral response was rapidly induced, occurring within 24 h of being transferred to plants grown at eCO2 and, once induced, persisted even after aphids were transferred to plants grown at ambient CO2. Escape responses were impaired due to reduced sensitivity to aphid alarm pheromone, (E)-β-farnesene, via an undefined plant-mediated mechanism. Aphid abundance often increases under eCO2, however, reduced efficacy of conspecific signalling may increase aphid vulnerability to predation, highlighting the need to study the chemical ecology of predator–prey interactions under environmental change.
KeywordsAphid Chemical signals Climate change Tri-trophic interactions Pheromones
We thank Alison Dobson, Carolin Schultz, Sheena Lamond, and Scott McKenzie for their assistance on this NERC CASE PhD project (NE/H018247/1).
- Dixon AFG (2000) Insect–predator prey dynamics. Ladybird beetles and biological control. Cambridge University Press, CambridgeGoogle Scholar
- Facey SL, Ellsworth D, Staley JT, Wright DJ, Johnson SN. 2014. Upsetting the order: how atmospheric and climate change affects predator–prey interactions. Curr Opin Insect Sci. doiGoogle Scholar
- IPCC (2013) Summary for policymakers. In: Stocker TF, Qin D, Plattner G–K, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013: The physical science basis contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, pp 3–29Google Scholar
- Ruxton GD, Sherratt TN, Speed MP (2004) Avoiding attack–the evolutionary ecology of crypsis, warning signals and mimicry. Oxford University Press, New YorkGoogle Scholar