Kinship composition in mammals

This is the final version. Available from the Royal Society via the DOI in this record. Data accessibility: The data, metadata and code are provided in the main text and the electronic supplementary materialUnderstanding the evolution of group-living and cooperation requires information on who animals live and cooperate with. Animals can live with kin, non-kin or both, and kinship structure can influence the benefits and costs of group-living and the evolution of within-group cooperation. One aspect of kinship structure is kinship composition, i.e. a group-level attribute of the presence of kin and/or non-kin dyads in groups. Despite its putative importance, the kinship composition of mammalian groups has yet to be characterized. Here, we use the published literature to build an initial kinship composition dataset in mammals, laying the groundwork for future work in the field. In roughly half of the 18 species in our sample, individuals lived solely with same-sex kin, and, in the other half, individuals lived with related and unrelated individuals of the same sex. These initial results suggest that it is not rare for social mammals to live with unrelated individuals of the same sex, highlighting the importance of considering indirect and direct fitness benefits as co-drivers of the evolution of sociality. We hope that our initial dataset and insights will spur the study of kinship structure and sociality towards new exciting avenues.European CommissionRepública Portuguesa/ Ministério Ciência, Tecnologia e Ensino Superio

Leaving a solitary life behind: Evolutionary processes leading to sociality in animals

Die Entwicklung stabiler Tiergruppen ist ein wichtiger Übergang in der Evolution, der aufgrund des selektiven Drucks, der mit sozialen Interaktionen verbunden ist, Veränderungen in der Populationsstruktur und in den aufkommenden Eigenschaften mit sich bringt. Die Sozialität basiert auf Kooperation, ein evolutionäres Puzzle in der darwinistischen Theorie, das auf der Konkurrenz um begrenzte Ressourcen beruht. Im ersten Kapitel stellen wir die Bedeutung der Verwandtschaftsselektion (i.e. Nepotismus) in Frage, um das Auftreten von Tiergruppen zu erklären, das das aktuelle Paradigma darstellt. Diese Theorie legt nahe, dass genetische Ähnlichkeit notwendig ist, um die Konkurrenz zwischen Individuen zu reduzieren, die eine Kooperation ermöglichen. Wir schlagen einen alternativen Rahmen vor, der die zahlreichen und unterschiedlichen Arten berücksichtigt, in denen die elterliche Fürsorge die Entwicklung des Gruppenlebens katalysiert haben könnte. Wir betonen die Bedeutung koevolutiver Prozesse zwischen Parasiten und Raubtieren mit elterlichen Investitionsstrategien, lange bevor ein Übergang zur Sozialität stattfinden kann. Aufbauend auf empirischen und theoretischen Erkenntnissen aus einem breiten Spektrum von Taxa, einschließlich Wirbeltieren und wirbellosen Tieren, schlagen wir vor, dass direkte Fitnessvorteile, die sich aus dem selektiven Druck ergeben, der mit der Evolution der elterlichen Fürsorge verbunden ist, die Kraft hinter dem Auftreten von Tiergruppen sind. In diesem Rahmen ist die Verwandtenselektion eher ein Verstärker oder sogar ein Nebenprodukt aus evolutionären Prozessen, die mit der elterlichen Fürsorge in Verbindung stehen, und nicht die Hauptvoraussetzung für die Entwicklung der Zusammenarbeit. Im zweiten Kapitel konzentrieren wir uns auf die Untersuchung fakultativ sozialer Spezies, um die Prozesse zu verstehen, die eine einsame Spezies zu einem Gruppenleben führen. In diesem Sinne beschreiben wir das Sozialsystem eines fakultativ sozialen Primaten mit gemeinschaftlicher Zucht, Microcebus murinus, anhand von Daten über mehr als 200 Individuen aus einer Wildpopulation. Durch die Untersuchung der gemeinsamen Schlafplatznutzung bei dieser einsamen Futtersuche wollen wir die soziale Flexibilität sowohl auf der Ebene der Art als auch auf der Ebene des Individuums charakterisieren. Wir finden Belege für die soziale Flexibilität bei philopatrischen Weibchen und zerstreuenden Männchen. Darüber hinaus zeigen wir, im Gegensatz zu früheren Ergebnissen, eine höhere Fähigkeit zur Sozialität und sozialen Flexibilität bei den Männchen. Unsere Ergebnisse deuten also darauf hin, dass die weibliche Gemeinschaftszucht möglicherweise nicht die einzige treibende Kraft für die Sozialität bei dieser Art ist, was den in Kapitel 1 dargelegten Rahmen kritisiert; und dass nicht verwandte Männchen genauso anfällig für die Bildung sozialer Gruppen sind wie verwandte Weibchen, was darauf hindeutet, dass die Verwandtschaftsauswahl auch nicht in der Lage ist, die Entwicklung der sozialen Systeme des Mausmakis zu erklären. Während wir in den ersten beiden Kapiteln die Übergänge zur Sozialität aus einer anpassungsorientierten Perspektive diskutiert haben, untersuchen wir in Kapitel 3.1 die Möglichkeit, dass die Sozialität bei Microcebus murinus ein passives Ergebnis der heterogenen Verteilung von Nahrungsressourcen und Schlafplätzen sein könnte. Wir finden keine Belege für einen Effekt der Verfügbarkeit von Nahrungsressourcen oder der Einschränkung der Nistplätze auf individuelle Sozialstrategien. Daher könnten die intrinsischen Vorteile, die mit dem gemeinsamen Schlafen und der gemeinsamen Nutzung eines Heimbereichs mit anderen verbunden sind, bei dieser Art im Spiel sein. In Kapitel 3.2 entwickeln wir die in Kapitel 3.1 angewandte Methode zur Beurteilung der Zuverlässigkeit der für jedes Individuum gesammelten Informationen, um mit Hilfe der Michaelis-Menten-Modellierung Heimatorte zu bauen. Wir glauben, dass dies ein potenziell nützliches Instrument für Studien in der freien Natur sein könnte, wo sowohl die Knappheit der Daten als auch die individuellen Unterschiede in der Menge der gesammelten Daten bewegungsökologische Analysen erschweren können. Abschließend betonen wir, dass die soziale Evolution ein vielfältiger Prozess ist, der mehrere Ebenen der Lebenskomplexität in sich birgt und miteinander verflochten ist und sich den Versuchen einer einheitlichen Erklärung ihrer Ursprünge widersetzt.The evolution of stable animal groups is a major transition in evolution entailing changes in population structure and emerging properties due to the selective pressures associated with social interactions. Sociality is based on cooperation, an evolutionary puzzle in Darwinian theory that is grounded on competition for limited resources. In the first chapter, we challenge the importance of kin selection (i.e. nepotism) to explain the appearance of animal groups, which is the current paradigm. This theory suggests that genetic similarity is needed to reduce competition between individuals allowing cooperation to be selected. We propose an alternative framework that takes into account the numerous and diverse ways in which parental care may have catalyzed the evolution of group living. We emphasize the importance of coevolutionary processes between parasites and predators with parental investment strategies long before transitions to sociality may occur. Building on empirical and theoretical evidence from a wide range of taxa, including vertebrates and invertebrates, we suggest that direct fitness benefits arising from selective pressures associated with parental care evolution are the force behind the appearance of animal groups. Under this framework, kin-selection is rather an enhancer or even a by-product derived from evolutionary processes related to parental care and not the main prerequisite for cooperation to evolve. In the second chapter, we focus on studying facultatively social species to understand the processes that lead a solitary species to become group-living. In this sense, we describe the social system of a facultatively social primate with communal breeding, Microcebus murinus, using data on more than 200 individuals from a wild population. By studying sleeping site sharing in this solitary foraging species, we aim to characterize the social flexibility both at the species as well as at the individual levels. We find evidence for social flexibility in philopatric females and dispersing males. Moreover, contrary to previous findings, we show a higher capacity for sociality and social flexibility in males. Thus, our results suggest that female communal breeding may not be the only force driving sociality in this species, criticizing the framework exposed in chapter 1; and that unrelated males may be as prone as related females to form social groups, which suggests that kin-selection is also unable to explain the evolution of mouse lemurs’ social systems. While in the first two chapters, we discussed transitions to sociality from an adaptationist perspective, in Chapter 3.1, we examine the possibility that sociality in Microcebus murinus may be a passive result of heterogeneous distribution of food resources and sleeping sites. We find no evidence for an effect of food resource availability or nesting limitation on individual social strategies. Thus, intrinsic benefits associated with sleeping together and sharing a home range with others may be at play in this species. In chapter 3.2, we develop the method used in chapter 3.1 to assess the reliability of information gathered per individual to construct home ranges using Michaelis-Menten modeling. We believe this might be a potentially useful tool for studies in the wild where scarcity of data as well as between-individual variation in the amount of data collected may hamper movement ecology analyses. We end by emphasizing that social evolution is a manifold process that embeds and intertwines several layers of life complexity, resisting attempts for unitary explanations of its origins

Exploring Animal Behavior Through Sound: Volume 1

This open-access book empowers its readers to explore the acoustic world of animals. By listening to the sounds of nature, we can study animal behavior, distribution, and demographics; their habitat characteristics and needs; and the effects of noise. Sound recording is an efficient and affordable tool, independent of daylight and weather; and recorders may be left in place for many months at a time, continuously collecting data on animals and their environment. This book builds the skills and knowledge necessary to collect and interpret acoustic data from terrestrial and marine environments. Beginning with a history of sound recording, the chapters provide an overview of off-the-shelf recording equipment and analysis tools (including automated signal detectors and statistical methods); audiometric methods; acoustic terminology, quantities, and units; sound propagation in air and under water; soundscapes of terrestrial and marine habitats; animal acoustic and vibrational communication; echolocation; and the effects of noise. This book will be useful to students and researchers of animal ecology who wish to add acoustics to their toolbox, as well as to environmental managers in industry and government

Exploring Animal Behavior Through Sound: Volume 1

This open-access book empowers its readers to explore the acoustic world of animals. By listening to the sounds of nature, we can study animal behavior, distribution, and demographics; their habitat characteristics and needs; and the effects of noise. Sound recording is an efficient and affordable tool, independent of daylight and weather; and recorders may be left in place for many months at a time, continuously collecting data on animals and their environment. This book builds the skills and knowledge necessary to collect and interpret acoustic data from terrestrial and marine environments. Beginning with a history of sound recording, the chapters provide an overview of off-the-shelf recording equipment and analysis tools (including automated signal detectors and statistical methods); audiometric methods; acoustic terminology, quantities, and units; sound propagation in air and under water; soundscapes of terrestrial and marine habitats; animal acoustic and vibrational communication; echolocation; and the effects of noise. This book will be useful to students and researchers of animal ecology who wish to add acoustics to their toolbox, as well as to environmental managers in industry and government

Behavioural responses of fish to parasitism and environmental conditions

Every aspect of an individual’s behaviour is, to some extent, mediated by parasite exposure. Potential hosts can, for example, initiate evasive behaviours towards infected conspecifics to reduce infection risk. If infected, individuals may exhibit adaptive behavioural responses aimed at reducing pathological symptoms. In addition to infection-mediated behavioural modifications, hosts behaviourally adapt to the environment in which they reside. Disentangling the effects of parasitism from environmental variables on host behaviour can be challenging. In a series of self-contained experiments, this thesis investigates three research areas. Firstly, how thermal and hydrological environmental conditions impact freshwater host-parasite interactions; secondly, how parasite infections mediate host behavioural modifications; and finally, how such behavioural changes have population level effects with respect to social structuring. The first experiment in this thesis describes how, when presented with a range of thermal conditions, Trinidadian guppies, Poecilia reticulata Peters 1859, infected with a common monogenean ectoparasite, Gyrodactylus turnbulli Harris 1986, frequent warmer thermal conditions to self-medicate against infection (Chapter 2). In a second experiment, G. turnbulli infected guppies experiencing dissimilar flow conditions showed a significant decrease in shoaling tendencies; but only in the absence of flowing water (Chapter 3). During this experiment, infected fish were observed increasing body contact with conspecifics: a behavioural adaptation presumably aimed at offloading parasite burdens (investigated in Chapter 4). Furthermore, infected hosts exhibited nocturnal restlessness, which may have further repercussions for host health (Chapter 5). Finally, parasite-mediated host behavioural modifications had significant population level effects with respect to social structuring. G. turnbulli infected guppies significantly increased their social rank within a population and instigated more contacts than they received, in contrast to their uninfected counterparts (Chapter 6). The infection status of an individual therefore determines its significance in mediating a population’s social dynamics, and so driving disease transmission processes