Morphological and population genomic evidence that human faces have evolved to signal individual identity.

Facial recognition plays a key role in human interactions, and there has been great interest in understanding the evolution of human abilities for individual recognition and tracking social relationships. Individual recognition requires sufficient cognitive abilities and phenotypic diversity within a population for discrimination to be possible. Despite the importance of facial recognition in humans, the evolution of facial identity has received little attention. Here we demonstrate that faces evolved to signal individual identity under negative frequency-dependent selection. Faces show elevated phenotypic variation and lower between-trait correlations compared with other traits. Regions surrounding face-associated single nucleotide polymorphisms show elevated diversity consistent with frequency-dependent selection. Genetic variation maintained by identity signalling tends to be shared across populations and, for some loci, predates the origin of Homo sapiens. Studies of human social evolution tend to emphasize cognitive adaptations, but we show that social evolution has shaped patterns of human phenotypic and genetic diversity as well

Facial Patterns are a Conventional Signal of Agonistic Ability in Polistes exclamans Paper Wasps

Some animals minimize the high costs of aggressive conflict by using conventional signals of agonistic ability to assess rivals prior to interacting. Conventional signals are more controversial than other signals of agonistic ability because they lack an inherent physical or physiological link with their bearer’s agonistic ability. Here, we test whether the variable brown facial stripes in Polistes exclamans paper wasps function as a conventional signal. Polistes exclamans were given the option of challenging or avoiding a rival with an experimentally altered facial pattern. Our results show that rival assessment is based on the facial patterns of rivals, as well as an individual’s own size, facial patterns, and nesting strategy. Individuals with larger body size and larger brown facial stripes were more likely to challenge rivals than individuals with smaller body size and smaller brown facial stripes. In addition, large individuals were more likely to challenge rivals with large brown facial stripes than small individuals, while an individual’s own body size did not influence whether or not they challenged rivals with small brown stripes. Individuals who previously nested in multiple queen groups approached rivals more rapidly than individuals who previously nested alone, suggesting that social experience also plays a role in rival assessment. Finally, rivals with small facial stripes were challenged more rapidly than those with large facial stripes. These results demonstrate that P. exclamans facial patterns function as a signal used to minimize the cost of conflict. However, individuals do not make simple decisions based on their rival’s signal alone, as an individual’s own social experience and agonistic abilities also influence rival assessment decisions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87088/1/j.1439-0310.2011.01967.x.pd

EVOLUTION OF IDENTITY SIGNALS: FREQUENCY-DEPENDENT BENEFITS OF DISTINCTIVE PHENOTYPES USED FOR INDIVIDUAL RECOGNITION

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74986/1/j.1558-5646.2009.00833.x.pd

Specialized visual learning of facial signals of quality in the paper wasp, P olistes dominula

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109618/1/bij12394.pd

How Does Individual Recognition Evolve? Comparing Responses to Identity Information in P olistes Species with and Without Individual Recognition

A wide range of complex social behaviors are facilitated by the recognition of individual conspecifics. Individual recognition requires sufficient phenotypic variation to provide identity information as well as receivers that process and respond to identity information. Understanding how a complex trait such as individual recognition evolves requires that we consider how each component has evolved. Previous comparative studies have examined phenotypic variability in senders and receiver learning abilities, although little work has compared receiver responses to identity information among related species with and without individual recognition. Here, we compare responses to identity information in two Polistes paper wasps: P. fuscatus, which visually recognizes individuals, and P. metricus , which does not normally show evidence of individual recognition. Although the species differ in individual recognition, the results of this study show that receiver responses to experimentally manipulated identity information are surprisingly similar in both species. Receivers direct less aggression toward identifiable individuals than unidentifiable individuals. Therefore, the responses necessary for individual recognition may pre‐date its evolution in the P. fuscatus lineage. Additionally, our data demonstrate the apparent binary differences in a complex behavior between the two species, such as individual recognition, likely involve incremental differences along a number of axes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102093/1/eth12191.pd

Individual Recognition in Paper Wasps: Correlated Evolution of Sender Phenotypes and Receiver Cognition

Recognition systems allow animals to discriminate among social partners on the basis of species, group membership, kinship or individual identity. Despite the fact that recognition is central to theories of social evolution, relatively little work has examined the processes by which the traits involved in recognition evolve. Notably, recognition often involves highly diverse traits used for recognition and specialized cognitive abilities, though the evolutionary origins of these traits has been largely unexplored. I consider three questions regarding the evolution of individual recognition, using Polistes wasps as a model. First, I examine the phenotypes used for recognition. Does selection favor individuals to broadcast their identity or is recognition akin to eavesdropping? Through a series of studies I show that the variable color patterns used by P. fuscatus to recognize conspecifics have arisen as the result of selection for distinctive easily recognizable identity signals. This work provides the first evidence that selection for recognition favors individuals to broadcast their identity. Selection for efficient recognition is likely to be a prominent mechanism maintaining polymorphism in social species. Second, I examine the specificity of cognitive processes associated with recognition. Do wasps use general learning mechanism for recognition or is it a specialized process? I demonstrate that P. fuscatus wasps have face-recognition specific learning adaptations, suggesting that cognitive evolution may be highly specific. Additionally, I show that wasps have surprisingly robust social memories despite their small brain size. Third, it is difficult to understand how sender and receiver phenotypes are elaborated in the absence of the other. I propose that the evolution novel recognition systems may be facilitated by pre-existing sender or receiver biases. I provide initial tests of the hypotheses, finding that sender bias is likely to be a widespread mechanism facilitating the evolution of novel recognition systems. Additionally, I provide experimental evidence for a receiver bias in Polistes wasps. The work presented in this dissertation present a multi-faceted examination of the evolution of an important social trait – individual recognition. Importantly, the results of this dissertation demonstrate that individual recognition will be an important model for studies of phenotypic polymorphic and cognitive evolution.PHDEcology and Evolutionary BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/93984/1/mic_1.pd

Recommended Practice for Use of Emissive Probes in Electric Propulsion Testing

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143022/1/1.B35697.pd

Constructing Arctic security: an inter-disciplinary approach to understanding security in the Barents region

Although traditionally Security Studies focused on military threats to states' survival, however, since the end of the Cold War the concept of security has widened and individuals and communities have gradually become viewed as appropriate referent objects of security. In the Arctic region, the human population are exposed to multiple non-traditional and non-military threats resulting from environmental, economic, and societal changes, which can be understood as threats to human security. In this article, we argue that a comprehensive approach to human security overlaps with the concept of societal security, and must therefore consider threats to collective identity and the essential conditions necessary for the maintenance and preservation of a distinct society. We use the human security framework as an analytical tool to study the specific challenges that threaten the Arctic population, and in turn the well-being of Arctic societies. The article demonstrates that using the concept of human security can promote societal security in the context of the Arctic

Selection on Coding and Regulatory Variation Maintains Individuality in Major Urinary Protein Scent Marks in Wild Mice

Recognition of individuals by scent is widespread across animal taxa. Though animals can often discriminate chemical blends based on many compounds, recent work shows that specific protein pheromones are necessary and sufficient for individual recognition via scent marks in mice. The genetic nature of individuality in scent marks (e.g. coding versus regulatory variation) and the evolutionary processes that maintain diversity are poorly understood. The individual signatures in scent marks of house mice are the protein products of a group of highly similar paralogs in the major urinary protein (Mup) gene family. Using the offspring of wild-caught mice, we examine individuality in the major urinary protein (MUP) scent marks at the DNA, RNA and protein levels. We show that individuality arises through a combination of variation at amino acid coding sites and differential transcription of central Mup genes across individuals, and we identify eSNPs in promoters. There is no evidence of post-transcriptional processes influencing phenotypic diversity as transcripts accurately predict the relative abundance of proteins in urine samples. The match between transcripts and urine samples taken six months earlier also emphasizes that the proportional relationships across central MUP isoforms in urine is stable. Balancing selection maintains coding variants at moderate frequencies, though pheromone diversity appears limited by interactions with vomeronasal receptors. We find that differential transcription of the central Mup paralogs within and between individuals significantly increases the individuality of pheromone blends. Balancing selection on gene regulation allows for increased individuality via combinatorial diversity in a limited number of pheromones

Carbon monoxide poisoning: novel magnetic resonance imaging pattern in the acute setting

The presentation of carbon monoxide (CO) poisoning is non-specific and highly variable. The diagnosis is made when a compatible history and examination occur in a patient with elevated carboxyhaemoglobin levels. The severity of intoxication is difficult to assess accurately based on laboratory markers alone. Magnetic resonance imaging (MRI) has been shown to have superior sensitivity to computed tomography for the detection of abnormalities post CO poisoning. We report a novel imaging pattern on MRI undertaken in the acute setting in a patient with CO intoxication. We also discuss the management and follow up of patients with CO poisoning