Reduced olfactory acuity in recently flightless insects suggests rapid regressive evolution

Area of Science:

• Insect olfaction
• Sensory adaptation
• Evolutionary biology

Background:

• Insects possess rapid olfactory capabilities, potentially linked to flight.
• Stoneflies offer a model to study flight-related adaptations due to wing polymorphism.

Purpose of the Study:

• To test the hypothesis that fast smelling is an adaptation for flight.
• To compare olfactory acuity between flighted and flightless stonefly lineages.

Main Methods:

• Analyzing olfactory receptor neuron responses in sympatric flighted and flightless stonefly ecotypes.
• Comparing olfactory acuity in genetically similar populations to control for confounding factors.

Main Results:

• Recently evolved flightless stonefly lineages exhibit reduced olfactory acuity.
• Independent wing reduction in different lineages correlates with parallel evolution of decreased olfactory acuity.
• Observed reductions in olfactory response strength and speed.

Conclusions:

• Flight imposes selective pressure on the speed and strength of olfactory receptor neuron responses.
• Reduced olfactory acuity in flightless lineages parallels rapid wing reduction.
• This study underscores the energetic costs of rapid olfaction and provides evidence for sensory adaptation driven by locomotion.