Mechanisms and Evolution of Communal Sexual Displays in Arthropods and Anurans

Advertisement signals of sexually displaying males are among the most widely and thoroughly studied phenomena in animal behavior. Many of our current advances in understanding sexual selection, signal evolution and species recognition, biomechanics, sensory and cognitive ecology, and neuro‐ethology derive from studies that focus on male signaling activities. Communal sexual displays are a subset of these signaling phenomena, and they merit special attention on two grounds: First, communal displays of acoustically and visually signaling animals are acknowledged to include some of the ‘‘great spectacles of the living world’’ (Wilson, 1975). Anyone who has borne witness to the chorusing of periodical cicadas in central and eastern North America or the collective flashing of fireflies in the Indo‐ Malayan region cannot help but marvel at the sheer numbers of individuals involved and the intensity of their collective signaling output. But, communal sexual displays are noteworthy for more than just masses of participants and their volume of sound or brilliance of light. In many cases, the signals of individual participants are precisely choreographed in space and time, often giving rise to striking alternation or synchrony between neighbors (Alexander, 1975). Here, underlying aesthetic sensibilities may account for much of our interest: Perhaps related to a concern with orderliness and pattern in the natural world, we remain fascinatedwith synchronous phenomena of all forms (Pikovsky et al., 2002; Strogatz, 2003; see Neda et al., 2000 for an intriguing example from human behavior), particularly when these events defy obvious explanation. And it is this latter point that brings us to our second reason for focusing attention on communal sexual displays: The mechanisms and evolution of an individual’s signaling are often concealed from casual view, and it is only when signaling is interactive that these