Social insects, such as bees, termites and ants, live together in groups as large as hundreds of thousands of individuals. In a colony of such size, allocation and sharing of tasks such as foraging and territory protection is essential to the efficient running of the population, therefore insects use a variety of communication systems. This essay discusses air and substrate borne vibrational communication, as well as pheromone and tactile systems, and provides examples of the utilisation of these systems by various insects.
Vibration is a common form of communication between insects. Those such as crickets, katydids, grasshoppers and cicadas use vibrations to produce an air-borne sound audible to the human ear (Cokl & Virant-Doberlet 2004), however in many insect species, soundless vibrations are produced (Cocroft & Rodriguez, 2005). This soundless vibrational communication takes place via a substrate or medium such as water or a plant; usually only detectable by humans using sensitive recording equipment (Cokl & Virant-Doberlet 2004).
In a 2001 article, Roces and Tautz state that in numerous ant species, worker ants produce vibrational signals audible to humans, however the ants are 'deaf', and therefore insensitive to this air-borne sound and instead are highly responsive to the substrate-borne component of the signal.
Cokl and Virant-Doberlet (2004) outline the main methods by which substrate-borne signals are produced. Percussion is when an insect strikes various body parts against a substrate, and tremulation is when it rocks and jerks its body without striking the substrate directly.
According to Cocroft and Rodriguez (2005), plant stems, leaves and roots are the main substrates used to transmit vibrational signals, particularly by herbivorous insects as they usually live on plants. The typical range of plant-borne vibrational communication between insects is from 30 centimetres to 2 metres (Keuper & Kuhne 1983, Henry & Wells 1990, Cokl &...