Journal Article

The evolutionary origins of ritualized acoustic signals in caterpillars

Kawahara, Akito Y., Yen, Shen-Horn, Sami, Abeer, Yack, Jayne E., Skevington, Jeffrey H., Smith, Myron L., Scott, Jaclyn L.

2010

Overview

Animal communication signals can be highly elaborate, and researchers have long sought explanations for their evolutionary origins. For example, how did signals such as the tail-fan display of a peacock, a firefly flash or a wolf howl evolve? Animal communication theory holds that many signals evolved from non-signalling behaviours through the process of ritualization. Empirical evidence for ritualization is limited, as it is necessary to examine living relatives with varying degrees of signal evolution within a phylogenetic framework. We examine the origins of vibratory territorial signals in caterpillars using comparative and molecular phylogenetic methods. We show that a highly ritualized vibratory signal—anal scraping—originated from a locomotory behaviour—walking. Furthermore, comparative behavioural analysis supports the hypothesis that ritualized vibratory signals derive from physical fighting behaviours. Thus, contestants signal their opponents to avoid the cost of fighting. Our study provides experimental evidence for the origins of a complex communication signal, through the process of ritualization. Many animals communicate through gestures, some caterpillars use scraping and drumming signals to ward off unwanted neighbours. Here, Scott et al . demonstrate that \"leg-like\" structures used by some caterpillar species to communicate evolved from legs that their ancestors used to walk.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/181 / 631/601/18 / Acoustics / Animal Communication / Animals / Behavior / Biological Evolution / Humanities and Social Sciences / Hypotheses / Lepidoptera - physiology / Molecular Sequence Data / Morphology / multidisciplinary / Phylogenetics / Phylogeny / Science / Science (multidisciplinary)