Elevated Carbon Dioxide Concentration Reduces Alarm Signaling in Aphids

Area of Science:

• Entomology
• Chemical Ecology
• Climate Change Biology

Background:

• Insects utilize olfactory cues for vital communication, including alarm signaling.
• Greenhouse gas increases may alter insect chemical communication, but impacts on pheromones are understudied.

Purpose of the Study:

• To investigate how elevated carbon dioxide (CO2) affects alarm signaling dynamics in pea aphids (Acyrthosiphon pisum).
• To assess CO2 impacts on alarm pheromone (E)-β-farnesene (Eβf) production, emission, perception, and aphid escape responses.

Main Methods:

• Pea aphids were reared under ambient and elevated CO2 concentrations across multiple generations.
• Eβf production, emission, neuronal perception, and colony-level escape behaviors were quantified.

Main Results:

• Elevated CO2 significantly reduced both Eβf production and emission in pea aphids.
• No differences in Eβf neuronal perception were detected between CO2 treatments.
• Aphid colony escape responses to alarm pheromone were significantly diminished under elevated CO2.

Conclusions:

• Increased atmospheric CO2 impairs chemical communication in pea aphids, specifically their alarm signaling system.
• These disruptions could have cascading ecological effects on aphid interactions with other trophic levels.