Complexity of mutual communication in animals exemplified by paired dances in the red-crowned crane

Abstract

Non-human animals commonly perform mutual communication in which two individuals simultaneously exchange information in an interaction that can comprise multiple components and multimodal signals. The forms of mutual communication vary widely, ranging from simple greeting ceremonies to complex paired dances including multiple behavioural elements. Our understanding of mutual communication lags markedly because few systematic studies have examined this topic. In this review, we used the example of paired dances in red-crowned cranes (Grus japonensis) to examine two important aspects of mutual communication: structure and function. We reviewed the difficulty analysing the key characteristics of structure quantitatively (e.g. sequential pattern and complexity), and examined suitable analytic methods such as determining the four levels of its characteristics. We proposed that a combination of current methods and new methods, such as the Shannon entropy index and temporal associations among behavioural elements, is necessary to quantify the complexity of mutual communication. Regarding the function of paired dances, we critically discuss the pair bond hypothesis, which suggests that a paired dance strengthens pair bonds in monogamous, long-living birds. Testing this classical hypothesis remains a challenge due to the difficulty of performing quantitative analyses of paired dances and the ambiguous concept of pair bonds. We hope that the questions and predictions raised in this paper will encourage future research on mutual communication in non-human animals.

Couples showing off: Audience promotes both male and female multimodal courtship display in a songbird

“…Therefore, here, we sought to examine the functions of both male and female courtship within a social environment. In some socially monogamous avian species, both sexes engage in courtship displays, such as song duetting ( 8 ), and multimodal courtship displays [for example, magpie-larks ( 9 ), albatrosses ( 10 ), cranes ( 11 , 12 ), and grebes ( 13 )]. These types of mutual courtship displays are assumed to play an important role in pair bonding and its maintenance ( 14 , 15 ), and thus have the potential to convey information related to mating status, which could be useful for mating rivals or individuals who seek opportunities for extra-pair mating.…”

Sexual selection in Estrildid finches, with further review of the evolution of nesting material holding display in relation to cooperative parental nesting

“…Secondly, as shown in the Java sparrow (Lonchura oryzivora), in which duet dancing is a key predictor of mating success (Soma & Iwama, 2017), behavioural displays that allow interactive communication between males and females can contribute to pairformation, and possibly pair-bonding as well (cf. Hall, 2004;Hall & Magrath, 2007;Ręk & Magrath, 2016;Takeda & Kutsukake, 2018).…”