Behavioral syndromes in paper wasps: Links between social and non-social personality in .

Although much work has focused on non-social personality traits such as activity, exploration, and neophobia, there is a growing appreciation that social personality traits play an important role in group dynamics, disease transmission, and fitness and that social personality traits may be linked to non-social personality traits. These relationships are important because behavioral syndromes, defined here as correlated behavioral phenotypes, can constrain evolutionary responses. However, the strength and direction of relationships between social and non-social personality traits remain unclear.

Viewpoint-independent face recognition via extrapolation in paper wasps.

Visual recognition of three-dimensional signals, such as faces, is challenging because the signals appear different from different viewpoints. A flexible but cognitively challenging solution is viewpoint-independent recognition, where receivers identify signals from novel viewing angles. Here, we used same/different concept learning to test viewpoint-independent face recognition in Polistes fuscatus, a wasp that uses facial patterns to individually identify conspecifics.

Field-realistic exposure to neonicotinoid and sulfoximine insecticides impairs visual and olfactory learning and memory in Polistes paper wasps.

Exposure to insecticides may contribute to global insect declines due to sublethal insecticide effects on non-target species. Thus far, much research on non-target insecticide effects has focused on neonicotinoids in a few bee species. Much less is known about effects on other insect taxa or newer insecticides, such as sulfoxaflor.

Honeybee visitation to shared flowers increases prevalence in bumblebees.

is a widespread pollinator parasite that commonly infects honeybees and wild pollinators, including bumblebees. Honeybees are highly competent hosts and previous work in experimental flight cages suggests can be transmitted during visitation to shared flowers. However, the relationship between floral visitation in the natural environment and the prevalence of among multiple bee species has not been explored.

Habitat quality influences pollinator pathogen prevalence through both habitat-disease and biodiversity-disease pathways.

The dilution effect hypothesis posits that increasing biodiversity reduces infectious disease transmission. Here, we propose that habitat quality might modulate this negative biodiversity-disease relationship. Habitat may influence pathogen prevalence directly by affecting host traits like nutrition and immune response (we coined the term "habitat-disease relationship" to describe this phenomenon) or indirectly by changing host biodiversity (biodiversity-disease relationship).

Social experience drives the development of holistic face processing in paper wasps.

Most recognition is based on identifying features, but specialization for face recognition in some taxa relies on a different mechanism, termed 'holistic processing' where facial features are bound together into a gestalt which is more than the sum of its parts. Although previous work suggests that extensive experience may be required for the development of holistic processing, we lack experiments that test how age and experience interact to influence holistic processing. Here, we test how age and experience influence the development of holistic face processing in Polistes fuscatus paper wasps.

Paper wasps form abstract concept of 'same and different'.

Concept formation requires animals to learn and use abstract rules that transcend the characteristics of specific stimuli. Abstract concepts are often associated with high levels of cognitive sophistication, so there has been much interest in which species can form and use concepts. A key abstract concept is that of sameness and difference, where stimuli are classified as either or an original stimulus.

The establishment and maintenance of dominance hierarchies.

Animal groups are often organized hierarchically, with dominant individuals gaining priority access to resources and reproduction over subordinate individuals. Initial dominance hierarchy formation may be influenced by multiple interacting factors, including an animal's individual attributes, conventions and self-organizing social dynamics. After establishment, hierarchies are typically maintained over the long-term because individuals save time, energy and reduce the risk of injury by recognizing and abiding by established dominance relationships.

Pollinator community species richness dilutes prevalence of multiple viruses within multiple host species.

Most pathogens are embedded in complex communities composed of multiple interacting hosts, but we are still learning how community-level factors, such as host diversity, abundance, and composition, contribute to pathogen spread for many host-pathogen systems. Evaluating relationships among multiple pathogens and hosts may clarify whether particular host or pathogen traits consistently drive links between community factors and pathogen prevalence. Pollinators are a good system to test how community composition influences pathogen spread because pollinator communities are extremely variable and contain several multi-host pathogens transmitted on shared floral resources.

Individual recognition is associated with holistic face processing in paper wasps in a species-specific way.

Most recognition is based on identifying features, but specialization for face recognition in primates relies on a different mechanism, termed 'holistic processing' where facial features are bound together into a gestalt which is more than the sum of its parts. Here, we test whether individual face recognition in paper wasps also involved holistic processing using a modification of the classic part-whole test in two related paper wasp species: , which use facial patterns to individually identify conspecifics, and , which lacks individual recognition. We show that use holistic processing to discriminate between face images but not face images.

Wasps Use Social Eavesdropping to Learn about Individual Rivals.

Many animals minimize the costs of conflict by using social eavesdropping to learn about the fighting ability of potential rivals before they interact. Learning about individual conspecifics via social eavesdropping allows individuals to assess potential opponents without personal risk. However, keeping track of a network of individually differentiated social relationships is thought to be cognitively challenging.

Complex signals alter recognition accuracy and conspecific acceptance thresholds.

Many aspects of behaviour depend on recognition, but accurate recognition is difficult because the traits used for recognition often overlap. For example, brood parasitic birds mimic host eggs, so it is challenging for hosts to discriminate between their own eggs and parasitic eggs. Complex signals that occur in multiple sensory modalities or involve multiple signal components are thought to facilitate accurate recognition.

The challenge hypothesis in insects.

The 'challenge hypothesis' provides a predictive framework for how the social environment influences within-species variation in hormone titers. High testosterone levels are beneficial during reproduction and competition, but they also impose costs because they may suppress traits like parental care and immunity. As a result, the challenge hypothesis predicts that individuals will change their testosterone levels to match the current social environment.

Transitive inference in Polistes paper wasps.

Transitive inference (TI) is a form of logical reasoning that involves using known relationships to infer unknown relationships (A > B; B > C; then A > C). TI has been found in a wide range of vertebrates but not in insects. Here, we test whether Polistes dominula and Polistes metricus paper wasps can solve a TI problem.

Developmental plasticity and the origin of novel communication systems: Individual recognition in Polistes wasps.

Although developmental plasticity facilitates the evolutionary origin of many traits, the role of plasticity in the origin of novel communication systems has received little attention. If plasticity mediates the origin of new communication systems, exposure to a novel environment will induce new traits that could function as signals or receiver responses. Here, we test whether plasticity facilitates the origin of individual recognition.

WASPnest: a worldwide assessment of social Polistine nesting behavior.

Cooperative breeding decreases the direct reproductive output of subordinate individuals, but cooperation can be evolutionarily favored when there are challenges or constraints to breeding independently. Environmental factors, including temperature, precipitation, latitude, high seasonality, and environmental harshness have been hypothesized to correlate with the presence of cooperative breeding. However, to test the relationship between cooperation and ecological constraints requires comparative data on the frequency and variation of cooperative breeding across differing environments, ideally replicated across multiple species.

Intraspecific Variation in Learning: Worker Wasps Are Less Able to Learn and Remember Individual Conspecific Faces than Queen Wasps.

Research on individual recognition often focuses on species-typical recognition abilities rather than assessing intraspecific variation in recognition. As individual recognition is cognitively costly, the capacity for recognition may vary within species. We test how individual face recognition differs between nest-founding queens (foundresses) and workers in Polistes fuscatus paper wasps.

queens exhibit personality variation and behavioral syndromes.

Consistent differences in behavior between individuals, otherwise known as animal personalities, have become a staple in behavioral ecology due to their ability to explain a wide range of phenomena. Social organisms are especially serviceable to animal personality techniques because they can be used to explore behavioral variation at both the individual and group level. Despite the success of personality research in social organisms generally, and social Hymenoptera in particular, social wasps (Vespidae) have received little to no attention in the personality literature.

Rapid juvenile hormone downregulation in subordinate wasp queens facilitates stable cooperation.

In many cooperatively breeding animals, subordinate group members have lower reproductive capacity than dominant group members. Theory suggests subordinates may downregulate their reproductive capacity because dominants punish subordinates who maintain high fertility. However, there is little direct experimental evidence that dominants cause physiological suppression in subordinates.

Cognitive specialization for learning faces is associated with shifts in the brain transcriptome of a social wasp.

The specialized ability to learn and recall individuals based on distinct facial features is known in only a few, large-brained social taxa. Social paper wasps in the genus are the only insects known to possess this form of cognitive specialization. We analyzed genome-wide brain gene expression during facial and pattern training for two species of paper wasps (, which has face recognition, and , which does not) using RNA sequencing.

Signal function drives phenotypic and genetic diversity: the effects of signalling individual identity, quality or behavioural strategy.

Animal coloration is influenced by selection pressures associated with communication. During communication, signallers display traits that inform receivers and modify receiver behaviour in ways that benefit signallers. Here, we discuss how selection on signallers to convey different kinds of information influences animal phenotypes and genotypes.

Heritable variation in colour patterns mediating individual recognition.

Understanding the developmental and evolutionary processes that generate and maintain variation in natural populations remains a major challenge for modern biology. Populations of paper wasps have highly variable colour patterns that mediate individual recognition. Previous experimental and comparative studies have provided evidence that colour pattern diversity is the result of selection for individuals to advertise their identity.

Socially selected ornaments influence hormone titers of signalers and receivers.

Decades of behavioral endocrinology research have shown that hormones and behavior have a bidirectional relationship; hormones both influence and respond to social behavior. In contrast, hormones are often thought to have a unidirectional relationship with ornaments. Hormones influence ornament development, but little empirical work has tested how ornaments influence hormones throughout life.

Socially selected ornaments and fitness: Signals of fighting ability in paper wasps are positively associated with survival, reproductive success, and rank.

Many animals have ornaments that mediate choice and competition in social and sexual contexts. Individuals with elaborate sexual ornaments typically have higher fitness than those with less elaborate ornaments, but less is known about whether socially selected ornaments are associated with fitness. Here, we test the relationship between fitness and facial patterns that are a socially selected signal of fighting ability in Polistes dominula wasps.