Ruhr University Bochum, Faculty of Biology and Biotechnology, Bochum, Germany.
J Exp Biol. 2013 Sep 1;216(Pt 17):3249-56. doi: 10.1242/jeb.086991.
Fungus-growing higher termites build long subterranean galleries that lead outwards from the nest to foraging sites. When soldiers are disturbed, they tend to drum with their heads against the substrate and thereby create vibrational alarm signals. The present study aimed at describing these acoustic signals, how they are elicited, produced and perceived, and how these signals propagate within the galleries and nests over long distances in two termite species of the Southern African savannah, Macrotermes natalensis and an Odontotermes sp. The signals consist of trains of pulses with a pulse repetition rate of 10-20 Hz. The galleries have physical features that promote vibrational communication and are used as channels for long-distance communication. In M. natalensis, the signal propagation velocity is ~130 m s(-1) and the signals are attenuated by ~0.4 dB per centimetre distance. Nestmates are extremely sensitive to these vibrations with a behavioural threshold amplitude of 0.012 m s(-2). Workers respond by a fast retreat into the nest and soldiers are recruited to the source of vibration. Soldiers also start to drum with a reaction time of about 0.3 s, thereby amplifying the intensity of the signal. This social long-distance communication through chains of signal-reamplifying termites results in a relatively slow propagation (1.3 m s(-1)) of the signal without decrement over distances of several metres.
真菌培养的高等白蚁会建造通往觅食地的长地下长廊。当兵蚁受到干扰时，它们往往会用头撞击基质，从而产生振动警报信号。本研究旨在描述这两种非洲南部草原白蚁，即非洲大白蚁和一种奥多白蚁的声学信号，包括它们是如何被引出、产生和感知的，以及这些信号如何在长廊和巢穴中远距离传播。这些信号由脉冲串组成，脉冲重复率为 10-20 Hz。长廊具有促进振动通讯的物理特征，并被用作远距离通讯的通道。在 M. natalensis 中，信号传播速度约为 130 m s(-1)，信号每厘米衰减约 0.4 dB。巢内同伴对这些振动极其敏感，行为阈值幅度为 0.012 m s(-2)。工蚁会迅速退回到巢穴中，而兵蚁则被招募到振动源。兵蚁也会在大约 0.3 s 的反应时间内开始击鼓，从而放大信号强度。这种通过一连串信号放大白蚁的社会远距离通讯导致信号传播速度相对较慢（1.3 m s(-1))，在数米的距离内没有递减。
