Diversity

Vibratory senses are ubiquitous in insects so that it is not surprising that more and more examples of vibratory signalling systems are being discovered regularly in almost all insect orders. It is possible that vibratory communication is a basic characteristic of the Insecta, or at least anyway of the Neoptera. The recent classification of insect orders adopted by Gullan and Cranston (2005) is followed here.

Among the Polyneoptera, one of the basal groups, the stoneflies and their relatives (Plecoptera) produce a variety of substrate transmitted signals by either percussion or tremulation or a combination of both (Stewart and Sandberg, Chapter 12). The Orthoptera sensu lato of course include many of the most obvious insect singers, crickets, grasshoppers, bushcrickets, etc., in which loud airborne signals are widely used and well studied (recently by Gerhard and Huber, 2002; and in this book by Heller, Chapter 9, and Bukhvalova, Chapter 14).

The Hemiptera, the biggest order in the Paraneoptera, includes the other well-known group which produces loud airborne acoustic signals. These are restricted to the one family Cicadidae, of which the typical male tymbal mechanism with associated resonant air sac is completely characteristic (Pringle, 1954; Young and Josephson, 1983a, 1983b; and in this book, Boulard, Chapter 25). Other families of Hemiptera, including many Heteroptera (Gogala, Chapter 21) and Homoptera (Cocroft and McNett, Chapter 23; Tishechkin, Chapter 24 and Chapter 27; Kanmiya, Chapter 28) are characterised by the production of often complex, low intensity, substrate transmitted acoustic signals. In most Homoptera Auchenorrhycha there are complicated, but little understood, mechanisms which resemble to varying degrees the tymbal system of cicadas, but always lack the associated air sac. Complex patterned, damped, low intensity calls are characteristic of many of these species (Claridge, 1985a, 1985b). Comparative physiological studies are urgently needed for these families. We still have only the wonderful classic, but now very old, work of Ossiannilsson (1949).

Within the Endopterygota sound production has been noted in some species of most orders. The basal Neuropterids are characterised by tremulation and percussive mechanisms widely used in courtship and species recognition and which have been greatly elucidated by Henry (Chapter 10). The enormous order, Coleoptera, includes many groups in which supposed stridulatory organs were early described. Charles Darwin (1871) documented many of these as apparent examples of sexual selection in the late 19th century. Wessel (Chapter 30) provides a useful brief overview of this diversity within the order, and Kasper and Hirschberger (Chapter 31) describe their detailed work on acoustic communication in one group of dung beetles, species of Aphodius.

Among the Diptera many groups are known to use vibratory signals in communication. Particularly well studied are the Drosophilidae which signal by pulsed wing vibrations when in very close proximity (Bennet-Clark, 1971). Hoikkala here (Chapter 11) illustrates the patterns of such calls for numerous Drosophila species. Other vibratory mechanisms, resembling tremulation, are known in some groups of Diptera (Kanmiya, Chapter 29).

Few examples of acoustic communication are known for the Lepidoptera, but some families do possess tymbal systems, very similar to the true cicada type (Sales and Pye, 1974). The Hymenoptera, one of the biggest orders, is probably the least studied. Some parasitic chalcid wasps are known to use wing vibratory signals during courtship (e.g. Assem and Povel, 1973; Assem and Werren, 1994). Perhaps they may function as near field signals, much like those of Drosophila. Certainly vibratory signals are known to be important in eusocial Hymenoptera. Hrncir et al. (Chapter 32) give a fascinating account here of such signals and associated behaviour in social bees.

Most groups of insects have well-documented examples of acoustic signals and communication, but there is a wide open field for research with the technology which is now available. Many of the authors of this book outline the diversity as at present known.

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