Expanding the concept of social behavior to interspecific interactions

Abstract

In pretty much any species, an individual's survival and reproduction depends crucially on the outcome of interactions with other individuals. Key interactions may take place between individuals of the same species but also between individuals belonging to different species. However, the most accepted definition of social behavior only considers interactions between conspecifics. Here, we argue that the distinction between intra-and interspecific interactions is largely artificial and hinders the integration of the historically separately developed concepts. At the ultimate level, given that the ecological landscape of organisms is composed both by interactions with conspecifics and with heterospecifics, and both types of interactions may have evolutionary consequences. Although intraspecific interactions usually have a higher impact in fitness because in most species interactions relevant for reproduction (mating, parenting) exclusively involve conspecifics, and interactions relevant for survival are more probable between conspecifics because they share the same ecological niche, hence competing for the same resources (e.g., food, shelter), there are notable exceptions in both fitness components (e.g., heterospecific mating in parthenogenic all-female species; heterospecific brood parasitism; heterospecific aggression in sympatric species that compete for shared resources). At the proximate level, behaviors and cognitive decision-making rules used to interact with other organisms may be shared between intra-and interspecific interactions, and the mechanistic differences between conspecific social behaviors used in distinct functional domains, such as mating, aggression, or parenting, can be more expressive than those found within the same functional domain between conspecific and heterospecific behavior. Therefore, there are neither fundamental conceptual (ultimate) reasons, nor key differences in mechanisms underlying behaviors involved in conspecific vs. heterospecific interactions that support the exclusion of interspecific interactions from the conceptual framework of social behavior.

Serotonin blocker Ketanserin reduces coral reef fishCtenochaetus striatusaggressive behaviour during between-species social interactions

“…This suggests that the serotonin system has been co-opted to regulate aggression in general, both with individuals of the same or different species. The results thus contribute to the still relatively scarce evidence that interspecific interactions may be labelled as 'social' not only from a functional but also from a mechanistic perspective (Oliveira and Bshary, 2021).…”

“…Social behaviours can have both positive effects, such as grooming and helping, and negative effects, such as competition and aggression (Tinbergen, 2012). The functional definition of social behaviour implies that recipients can be conspecifics as well as heterospecifics (Oliveira and Bshary, 2021). However, such an inclusive approach may be challenged on a mechanistic level unless it can be shown that intra- and interspecific interactions are governed by the same underlying mechanisms (Oliveira and Bshary, 2021).…”

“…The functional definition of social behaviour implies that recipients can be conspecifics as well as heterospecifics (Oliveira and Bshary, 2021). However, such an inclusive approach may be challenged on a mechanistic level unless it can be shown that intra- and interspecific interactions are governed by the same underlying mechanisms (Oliveira and Bshary, 2021). Here, our focus is on physiological mechanisms such as endocrine systems.…”

Identification of reindeer fine-scale foraging behaviour using tri-axial accelerometer data

“…Monitoring animal behaviour enables a better understanding of animal behavioural ecology in an evolutionary context e.g., inter- and intra-specific interactions such as competition and population dynamics [ 1 ]. Investigation of fine-scale animal behaviour can improve the understanding of animals’ functional response to the environment [ 2 ] and provide an important indicator of animal welfare [ 3 ].…”

The Evolution of Social Behaviour

“…The issue includes Perspective and Reviews papers asking how cooperative breeding may help or hinder coping with environmental change (Komdeur & Ma, 2021), highlighting the possibility that sociality is more widespread in marine habitats than usually assumed (Mazzei & Rubenstein, 2021), or how individual social competence may further the evolution of sociality and vice versa (Taborsky, 2021). Oliveira and Bshary (2021) propose to include interspecific relationships into social behaviour, and Bender (2021) outlines the potential for ethology to improve the evolutionary understanding of human medical problems. Original Research papers ask whether naked mole rats express caste differentiation (Siegmann et al, 2021), whether rats are aware of the ability of partners to reciprocate food donations (Schweinfurth, 2021), propose novel imaging techniques in the study of sociality (Jungwirth et al, 2021), show how collective actions can lead to diversification of behaviours (Green et al, 2021) and illustrate the importance of the early social environment for learning abilities in cichlids (Fischer et al, 2021) and later life attraction to conspecific odours (Schneeberger & Eccard, 2021).…”