Vibrational Communication in Social Caterpillars

Both solitary and social species of caterpillars may generate vibrational signals that have a communicative function in an intraspecific context.  The signals are typically generated when a caterpillar at a feeding site or shelter is approached by a conspecific. The vibrational stimulus produced by the resident caterpillar functions to drive away the potential intruder. If the intruder caterpillar continues to approach, the resident caterpillar increases the rate of signaling and typically drives the intruder away. In this context, the vibrational signal functions in a manner similiar to the acoustical displays of territorial songbirds,  promotinge dispersal rather than aggregation.  The 'territorial' display of the cherry leaf roller Caloptilia serotinella is an example of this type of  'asocial' intraspecific signaling.

The cherry leaf roller Caloptilia serotinella produces three signals: scraping, plucking and vibration. Scraping, the most common signal, is generated when the caterpillar swings the anterior portion of its body from side to side against the surface of a leaf.  Plucking occurs when the caterpillar lifts it head and anterior body vertically, pulling up on the surface of the leaf.  The vibratory signal is least common and is generated when the caterpillar vibrates its throax horizontally.
The cherry leaf roller Caloptilia serotinella (Lepidoptera: Gracillaridae)
The resident Caloptilia caterpillar (larger) drives away an intruder by scraping and plucking its mandibles against the surface of the leaf.