The nonapeptides vasotocin, oxytocin and their homologues regulate a wide range of social behaviours such as mating, aggression, social recognition and parental care across vertebrates. These varied influences across diverse taxa suggest a highly-conserved, ancestral role for nonapeptides in animal social behaviour. Here, we address the role of nonapeptides in a foundational social behaviour, the tendency of individuals to group with conspecifics. We investigated the effects of administration of nonapeptides on shoaling behaviour in the guppy (Poecilia reticulata), a small freshwater fish that is a model system for studying the evolution of social behaviour in the wild. We conducted two experiments using intracerebroventricular administration in wild-origin guppies to investigate the effects of nonapeptides and their antagonists on grouping behaviour, focusing first on oxytocin, and then on vasotocin. We monitored shoaling behaviour for 2.5 h after each administration and found that after 90 min, oxytocin significantly increased social interaction, with a similar effect on shoaling behaviour. Vasotocin did not produce significant changes in social interaction or shoaling preferences, and putative receptor antagonists for oxytocin and vasotocin did not have clear behavioural effects. These findings show that central administration of oxytocin increases shoaling tendencies in guppies, suggesting it influences this fundamental social behaviour. We also found that effects were time-dependent, highlighting the importance of studying the temporal dynamics of nonapeptide actions on behaviour. Our work also demonstrates the feasibility of intracerebroventricular injections for central pharmacological manipulations in small fish, opening new potential avenues for behavioural neuroscience in non-model species.

Animals collect information about when to flee, where to feed, or where and with whom to breed. They can gather this information by sampling the environment (personal information), or by observing the behavior of others (inadvertent social information), or attending to signals made by others (communication). This article focuses on inadvertent social information. Models predict that animals will use inadvertent social information when the costs of gathering personal information are high, and when reliable social cues are readily available. In line with these predictions, migrants copy the breeding habitat choice of resident species, unsuccessful foragers copy successful foragers' patch choices, and young females copy the mate choice of more experienced conspecifics. Social information use can have positive, neutral, or negative effects on individuals producing information, and these fitness consequences can, in turn, select for true communication or concealment.

DNA methylation (DNAm) is a well-studied epigenetic mechanism implicated in environmentally induced phenotypes and phenotypic plasticity. However, few studies investigate the timescale of DNAm shifts. Thus, it is uncertain whether DNAm can change on timescales relevant for rapid phenotypic shifts, such as during the expression of short-term behavioural plasticity. DNAm could be especially reactive in the brain, potentially increasing its relevance for behavioural plasticity. Most research investigating neural changes in methylation has been conducted in mammalian systems, on isolated individuals, and using stressors that are less ecologically relevant, reducing their generalisability to other natural systems. We exposed pairs of male and female Trinidadian guppies (Poecilia reticulata) to alarm cue, conspecific skin extract that reliably induces anti-predator behaviour, or a control cue. Whole-genome bisulphite sequencing on whole brains at various time points following cue exposure (0.5, 1, 4, 24, and 72 h) allowed us to uncover the timescale of neural DNAm responses. Males and females both showed rapid shifts in DNAm in as little as 0.5 h. However, males and females differed in the time course of their responses: both sexes showed a peak in the number of loci showing significant responses at 4 h, but males showed an additional peak at 72 h. We suggest that this finding could be due to the differing longer-term plastic responses between the sexes. This study shows that DNAm can be rapidly induced by an ecologically relevant stressor in fish and suggests that DNAm could be involved in short-term behavioural plasticity.

Social learning, where animals learn from other individuals, occurs in many diverse species. The influential but debated ‘costly information’ hypothesis posits that animals will rely more on social information in high-risk contexts, such as under increased predation risk. We examined and compared the effects of perceived predation risk on social learning of foraging sites in female Trinidadian guppies from wild and domestic populations raised in common-garden environments. We used a demonstrator-observer pairing where a subject could observe conspecific ‘demonstrators’ feeding from one of two feeders, and measured whether the observer subsequently spent more time at a demonstrated or non-demonstrated feeder. We manipulated perceived predation risk using alarm cue (conspecific skin extract). Stress responses and social learning differed between the two populations. Most notably, high predation risk enhanced social learning in the wild-type guppies, but depressed it in the domestic guppies. Thus, fish from both populations were able to socially learn, but under opposing contexts. These results suggest social learning propensities are the product of multiple interacting systems, and biases to favour social learning can emerge dependent on evolutionary history and current conditions.

Early-life experiences can predict the environments experienced later in life, giving individuals an opportunity to develop adaptive behaviour appropriate to a likely future environment. Epigenetic mechanisms such as DNA methylation (DNAm) have been implicated in developmental behavioural plasticity; however, studies investigating this possibility are limited in taxonomic breadth and ecological relevance. We investigated the impact of early-life exposure to predation stress on behaviour and DNAm in the brains of Trinidadian guppies (Poecilia reticulata). We exposed guppies throughout development to either an alarm cue (conspecific skin extract), inducing predation stress, or a control cue (water) for 8 weeks and then raised them to adulthood under identical conditions. Then, we conducted two behavioural assays, an open-field and a grouping test, before performing whole-genome bisulfite sequencing on whole brains. Guppies exposed to the alarm cue during development exhibited increased grouping (shoaling) in adulthood compared to those exposed to the control treatment, but there were no detectable impacts on activity, boldness, or exploratory behaviour. We also identified stable shifts in brain DNAm in response to developmental alarm cue exposure in genes involved in behavioural regulation. Some differentially methylated sites were significantly associated with shoaling propensity in both males and females. Additionally, males and females differed in the magnitude of DNAm responses and the genes impacted, suggesting distinct roles for DNAm between the sexes. This study shows how early-life predation stress can induce behavioural changes in adulthood and that shifts in neural DNAm could be an underlying mechanism responsible for these changes.

Abstract Innovation, new or modified learned behaviour, is core to cultural evolution and fundamental to the success of humans. Innovations allow us to adapt to and change habitats, solve novel problems, and survive and flourish in diverse environments. Innovation also appears to be pervasive across the animal kingdom, with adaptive importance within a wide range of species. This chapter covers how innovation and its subcategories are defined and studied and its importance to both cultural and genetic evolution. The authors discuss the difficulty of creating useful, operational definitions that can link disparate fields, and controversies in the study of innovation, such as the independence of innovation from processes such as exploration and creativity. Considering costs and benefits to innovation, the authors address how individual, social, and ecological influences shape innovative propensities. The chapter finishes by discussing how cross-disciplinary research is key to resolving controversies within the field.

Behavioural plasticity allows organisms to respond to environmental challenges on short time scales. But what are the ecological and evolutionary processes that underlie behavioural plasticity? The answer to this question is complex and requires experimental dissection of the physiological, neural and molecular mechanisms contributing to behavioural plasticity as well as an understanding of the ecological and evolutionary contexts under which behavioural plasticity is adaptive. Here, we discuss key insights that research with Trinidadian guppies has provided on the underpinnings of adaptive behavioural plasticity. First, we present evidence that guppies exhibit contextual, developmental and transgenerational behavioural plasticity. Next, we review work on behavioural plasticity in guppies spanning three ecological contexts (predation, parasitism and turbidity) and three underlying mechanisms (endocrinological, neurobiological and genetic). Finally, we provide three outstanding questions that could leverage guppies further as a study system and give suggestions for how this research could be done. Research on behavioural plasticity in guppies has provided, and will continue to provide, a valuable opportunity to improve understanding of the ecological and evolutionary causes and consequences of behavioural plasticity.

This chapter begins in England in the early nineteenth century, when the printing industry, which had previously been conducted exclusively through manual labor, was rapidly mechanized through the application of steam power. It considers the major events in the industrialization of print such as the development of lithography and machine-made paper; the application of the steam engine to printing; and the worldwide distribution of books aided by steam ships and railways. Reader demonstrates that any scholarly investigation of the literary legacy of steam-driven presses must leave behind narrow disciplinary boundaries: “Literary scholars wishing to assert the importance of machine printing must necessarily place texts in relation not only to other works of literature but also to competing media: journalism, advertising, and other products of the print industry.”

Species are the main unit used to measure biodiversity, but different preferred operational criteria can lead to very different delineations. For instance, named primate species have more than doubled in number since 1982. Such increases have been partly attributed to a shift away from the "biological species concept" (BSC) in favor of less inclusive species criteria. Critics of recent changes in primate taxonomy have suggested taxonomic splitting may be biased toward certain clades and have unfavorable consequences for conservation. Here, we explore predictors of taxonomic splitting across primate taxa since the initial shift away from the BSC nearly 40 years ago. We do not find evidence that net diversification rate, the rate of lineage formation over evolutionary time, is significantly linked to splitting, contrary to expectations if new species concepts and taxonomic methods identify incipient species. We also do not find evidence that research effort in fields where work has been suggested to motivate splitting is associated with increases in species numbers among genera. To test the suggestion that splitting groups is likely to increase their perceived risk of extinction, we test whether genera that have undergone more splitting have also observed a greater increase in their proportion of threatened species since the initial shift away from older taxonomic methods. We find no cohesive signal of taxonomic splitting leading to higher threat probabilities across primate genera. Thus, our analysis suggests that the threat statuses of primate species are not being overwhelmingly driven by splitting. Regardless, we echo warnings that it is unwise for conservation to be reliant on taxonomic stability. Species (however defined) are not independent from one another, thus, monitoring and managing them as such may not meet the overarching goal of conserving biodiversity.

Learning to respond appropriately to novel dangers is often essential to survival and success, but carries risks. Learning about novel threats from others (social learning) can reduce these risks. Many species, including the Trinidadian guppy ( Poecilia reticulata ), respond defensively to both conspecific chemical alarm cues and conspecific anti-predator behaviours, and in other fish such social information can lead to a learned aversion to novel threats. However, relatively little is known about the neural substrates underlying social learning and the degree to which different forms of learning share similar neural mechanisms. Here, we explored the neural substrates mediating social learning of novel threats from two different conspecific cues (i.e. social cue-based threat learning). We first demonstrated that guppies rapidly learn about threats paired with either alarm cues or with conspecific threat responses (demonstration). Then, focusing on acquisition rather than recall, we discovered that phospho-S6 expression, a marker of neural activity, was elevated in guppies during learning from alarm cues in the putative homologue of the mammalian lateral septum and the preoptic area. Surprisingly, these changes in neural activity were not observed in fish learning from conspecific demonstration. Together, these results implicate forebrain areas in social learning about threat but raise the possibility that circuits contribute to such learning in a stimulus-specific manner.

Intraspecific variation in social behaviour is often observed among animal populations. Local predation risk can be a key driver of these differences, with populations that are exposed to greater threat typically showing greater aggregation and reduced intraspecific aggression. The Trinidadian guppy, Poecilia reticulata, is found in populations that vary dramatically in predation risk and show greater grouping and reduced agonism in high-predation populations compared to low-predation populations. The neurohormonal mechanisms that underpin these differences in behaviour across populations remain unknown and elucidating these mechanisms may help us to understand the evolution of behavioural diversity in this species. We predicted that guppies naturally exposed to higher predation risk would show greater expression of the isotocin system and reduced expression of the vasotocin system when compared to low-predation fish, because these peptides are thought to promote gregariousness and aggressivity respectively. We collected guppies of both sexes from high- and low-predation sites, replicated in two different Trinidadian rivers, and measured the brain gene expression of isotocin and vasotocin along with their central receptors. Contrary to our prediction, we found that high-predation guppies showed greater expression of vasotocin, while we did not find evidence that the populations differed in isotocin expression, nor in the expression of the receptors. These results support the hypothesis that vasotocin may act as a neural substrate for social variation in fishes but call into question generalisations about its specific role across species.

Learning allows animals to adaptively adjust their behaviour in response to variable but predictable environments. Stable aspects of the environment may result in evolved or developmental biases in the systems impacting learning, allowing for improved learning performance according to local ecological conditions. Guppies (Poecilia reticulata), like many animals, show striking colour preferences in foraging and mating contexts and guppy artificial selection experiments have found that the form and progress of evolved responses to coloured stimuli differ depending on stimulus colour. Blue colouration is thought to typically be a relatively unimportant food cue in guppies. This raises the possibility that learned foraging associations with blue objects are formed less readily than with other colours. Here, guppies were rewarded for foraging at green or blue objects in two experiments. Guppies readily foraged from these objects, but learning performance differed with rewarded object colour. With equal amounts of training, the preference for green objects became stronger than the preference for blue objects. These differences in performance were not attributable to differences in initial preferences or to foraging more on one colour during training. These findings suggest that associative pairings within a single sensory modality that do not have a historic relevancy can be more difficult for animals to learn even when there is no clear initial bias present.

Individuals often face unpredictable and harsh environments, presenting them with novel ecological problems. Behaviour can provide an adaptive response in such conditions and where these conditions vary between populations, we may predict development and evolution to shape differences in behaviour such as exploration, innovation, and learning, as well as other traits. Here, we compared in the wild the maze swimming performance of groups of female guppies from two Trinidadian populations that differ in numerous ecological characteristics, the Upper and Lower Aripo river. Compared to Upper Aripo fish, Lower Aripo fish were slower to complete the maze, our measure of propensity to innovate, and scored lower on a combined measure of activity and exploration. More active-exploratory groups were faster to complete the maze, but only in the Lower Aripo. We found no evidence for learning the maze. Our results suggest that activity-exploratory and innovative propensities can vary between populations, as can predictors of innovation. These findings are consistent with high predation risk shaping decreased activity-exploratory propensities, but further population comparisons are required to reliably determine the drivers of the observed population difference. Our results emphasize that individual and population differences in activity-exploration and innovation can be shaped by numerous factors.

Aggression is costly, and animals have evolved tactics to mitigate these costs. Submission signals are an underappreciated example of such adaptations. Here we review submissive behaviour, with an emphasis on non-primates. We highlight the design of submission signals and how such signals can reduce costs. Animal societies necessitate frequent social interactions, which can increase the probability of conflict. Where maintaining group proximity is essential, animals cannot avoid aggression by fleeing. Mutual interest between group members may also select for efficient conflict avoidance and resolution mechanisms. As a result, submission signals may be especially well developed among group living species, helping social animals to overcome potential costs of recurring conflict that could otherwise counter the benefits of group living. Therefore, submission signalling can be a crucial aspect of social living and is deserving of specific attention within the broader context of social evolution and communication.

Identifying the factors that influence species diversification is fundamental to our understanding of the evolutionary processes underlying extant biodiversity. Behavioural innovation, coupled with the social transmission of new behaviours, has been proposed to increase rates of evolutionary diversification, as novel behaviours expose populations to new selective regimes. Thus, it is believed that behavioural flexibility may play an important role in driving evolutionary diversification across animals. We test this hypothesis within the primates, a taxonomic group with considerable among-lineage variation in both species diversity and behavioural flexibility. We employ a time cut-off in our phylogeny to help account for biases associated with recent taxonomic reclassifications and compare three alternative measures of diversification rate that consider different phylogenetic depths. We find that the presence of behavioural innovation and social learning are positively correlated with diversification rates among primate genera, but not at shallower phylogenetic depths. Given that we find stronger associations when examining older rather than more recent diversification events, we suggest that extinction resistance, as opposed to speciation, may be an important mechanism linking behavioural flexibility and primate diversification. Our results contrast with work linking behavioural flexibility with diversification of birds at various phylogenetic depths. We offer a possible dispersal-mediated explanation for these conflicting patterns, such that the influence behavioural flexibility plays in dictating evolutionary trajectories differs across clades. Our results suggest that behavioural flexibility may act through several different pathways to shape the evolutionary trajectories of lineages.

This paper reads Oscar Wilde's aphoristic style in terms of the note-taking practices he develops as an undergraduate at Oxford. It treats his use of small, mobile pieces of language as a strategy for dealing with methodological uncertainty in a time of curricular upheaval. His trademark style is perhaps best understood as a form of social notation, whereby pieces of information behave as actors seeking sociality and recombination, rather than placement in systematic arrangements. One significant unpublished source - the Notebook on Philosophy' - discloses Wilde's engagement with a surprising aphoristic precursor, Francis Bacon, who deploys the form for similar purposes. In modelling a form of non-teleological informational assembly, Wilde's notebooks also body forth the utopian social life he conceives in his later critical writings.

This article proposes a way of linking textual form and the social world. The forms in question are the notebooks of Gerard Manley Hopkins, specifically those he kept between 1866 and 1875, a period that begins with his conversion to Catholicism, initiation into Jesuit training, and rejection of poetry. These five notebooks (A1–A5) have struck some readers as intensely asocial . Their creator was famously resistant to circulation and readership, on one hand (“Please not to read,” he inscribes on the inside front cover of the first), and more concerned with natural than human phenomena, on the other. I show instead that the notebooks project networks of relation between humans, objects, and the natural world. My hope is that what follows will refresh some of the ways we think about and navigate online social forms in the twenty-first century.

Animals have access to information produced by the behaviour of other individuals, which they may use (“social information use”) and learn from (“social learning”). The benefits of using such information differ with socio-ecological conditions. Thus, population differences in social information use and social learning should occur. We tested this hypothesis with a comparative study across five wild populations of Trinidadian guppies () known to differ in their ecology and social behaviour. Using a field experiment, we found population differences in how guppies used and learned from social information, with only fish from one of the three rivers studied showing evidence of social information use and social learning. Within this river, populations differed in how they employed social information: fish from a high-predation regime where guppies exhibit high shoaling propensities chose the same foraging location than conspecifics, while fish from a low-predation regime with reduced shoaling propensities chose and learned the opposite foraging location than conspecifics. We speculate that these differences are due to differences in predation risk and conspecific competition, possibly mediated via changes in grouping tendencies. Our results provide evidence that social information use and social learning can differ across animal populations and are influenced by socio-ecological factors.

1. There is considerable diversity in brain size within and among species, and substantial dispute over the causes, consequences and importance of this variation. Comparative and developmental studies are essential in addressing this controversy. 2. Predation pressure has been proposed as a major force shaping brain, behaviour and life history. The Trinidadian guppy, Poecilia reticulata, shows dramatic variation in predation pressure across populations. We compared the brain mass of guppies from high and low predation populations collected in the wild. Male but not female guppies exposed to high predation possessed heavier brains for their body size compared to fish from low predation populations. 3.The brain is a plastic organ, so it is possible that the population differences we observed were partly due to developmental responses rather than evolved differences. In a follow-up study, we raised guppies under cues of predation risk or in a control condition. Male guppies exposed to predator cues early in life had heavier brains relative to their body size than control males, while females showed no significant effect of treatment. 4. Collectively our results suggest that male guppies exposed to predation invest more in neural tissue, and that these differences are at least partly driven by plastic responses.