Abdominal sensing of substrate vibrations in insects

Area of Science:

• * Zoology
• * Neuroethology
• * Sensory Biology

Background:

• * Mechanosensation is a fundamental sensory modality in insects, with receptors distributed across all body parts.
• * Specialized sensory organs, particularly in the legs, are known for perceiving substrate vibrations.
• * Insects also interact with substrates using abdominal body parts, suggesting potential for vibration detection.

Purpose of the Study:

• * To investigate the vibrational sensitivity of abdominal nerves in two evolutionarily distinct insect species.
• * To compare the vibrational sensitivity of abdominal sense organs with those in the legs.
• * To determine the contribution of abdominal chordotonal organs to vibration perception.

Main Methods:

• * Extracellular recordings from abdominal nerves in grasshoppers (Schistocerca gregaria) and cicadas (Okanagana rimosa).
• * Application of controlled vibrational stimuli (30 Hz - 10 kHz, 0.01 - 10 m/s²) to the caudal abdomen.
• * Recording from nerves innervating mechanosensitive chordotonal organs.

Main Results:

• * Abdominal nerves in Schistocerca gregaria exhibited vibrational sensitivity comparable to leg nerves.
• * Abdominal sense organs in Okanagana rimosa demonstrated even higher sensitivity than leg-associated organs.
• * Abdominal tympanate ears in both species were also responsive to substrate vibrations.

Conclusions:

• * Chordotonal organs located in the insect abdomen are significant contributors to vibration perception.
• * Vibrational sensitivity is not limited to the legs, with abdominal organs playing a crucial role.
• * This finding broadens our understanding of insect sensory ecology and mechanotransduction.