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The founding individuals of a new group or lineage are uniquely poised to have long-lasting effects on their descendants. Here we explore how the behavioural traits of new foundresses influence their task allocation strategies and the downstream collective behaviour of their colonies. We collected individual paper wasp (Polistes metricus) queens from the wild and measured their boldness, aggressiveness, exploration, activity and time budgets in the laboratory. We then provided queens with food and nest materials and waited for their workers to eclose. We subsequently tested for links between queen behavioural traits (e.g. boldness, aggressiveness) and the collective aggressiveness of their colonies, as estimated by the number of workers that responded to and stung a model predator. We found that bolder queens (i.e. queens that were less likely to leave their nests after repeated exposure to an agonistic stimulus) spent more time nest guarding, reared more workers and produced groups that were less responsive to a model predator. Thus, there appears to be parent–offspring, or queen–worker, resemblance in the degree to which individuals remain on their nests in different social contexts (solitary queen versus queen + her worker group). To our knowledge this represents the first study to explicitly test for links between individual variation in foundress behaviour, worker production and intercolony collective behaviour; the results highlight the possibility that cross-contextual and transgenerational behavioural links could be a reasonably common and potentially important phenomenon in complex societies.

Animals frequently compete over limited resources such as food, territories or mating opportunities. Contest behaviour varies based on factors such as the value of the contested resources and the agonistic ability of rivals. Much work on animal contests has examined aggression, but vigilance, or a state of heightened alertness directed towards specific stimuli, may also be an important component of competition in many species. In this study, we measure the relationships among social vigilance, aggression, agonistic ability and resource value during staged contests over nest ownership in Polistes dominula nest-founding wasps. Our results show that both social vigilance and aggression are involved in mediating social risk during contests. Nest owner vigilance towards a rival increased with the time of season, a measure of nest value. Owner vigilance was also positively associated with aggression such that more aggressive owners were more vigilant. During contests, aggression of owners and rivals was influenced by different factors. Owner aggression was positively associated with nest size, another measure of nest value, while rival aggression was unrelated to nest size. Instead, rival aggression was associated with facial patterns that function as signals of agonistic ability; rivals were less aggressive to owners that signalled high agonistic ability than they were to owners that signalled low agonistic ability. The distinct predictors of contest behaviour between owners and rivals indicate that competitive role has a surprisingly strong influence on cues used to inform contest behaviour. Differences may occur because owners and rivals have different information and/or motivation. These results also suggest that social vigilance and aggression may be complementary behaviours that animals use to mitigate social threat.

In many signalling systems, intraspecific variation in recognition abilities is based on developmental stage, experience or caste. However, the occurrence of intraspecific variation in recognition has not been thoroughly examined in species with individual recognition. For example, previous work has shown that individual recognition is an important aspect of the social life of Polistes fuscatus (paper wasp) nest-founding queens, as individual recognition stabilizes dominance interactions and reduces aggression. To date, the potential for individual recognition among P. fuscatus workers has been largely ignored. Here, we explore whether there is intraspecific variation in individual recognition by testing P. fuscatus worker recognition abilities in a series of staged contests. The results indicate that P. fuscatus workers are capable of individual recognition: focal workers paired with previously encountered partners experienced significantly less aggression and more nonaggressive bodily contact than focal workers paired with unknown social partners. We propose two potential explanations for individual recognition among workers: (1) worker individual recognition may be favoured because it provides social benefits to workers, or (2) worker individual recognition may be a byproduct of selection for individual recognition in foundresses. Individual recognition is often considered a cognitively challenging form of recognition, so future studies that compare the sophistication of recognition across castes will be useful to assess whether there are more subtle differences in cognitive abilities or recognition behaviour between P. fuscatus nest-founding queens and workers.

Discrimination among potential partners is a critical step in sexual selection to avoid wasting reproductive resources on an unsuitable mate. In the female-dominated hymenopteran societies males have often been regarded as ‘flying sperm containers’ spending all their time and energy in trying to acquire a mate. We investigated the male sexual preference for potential partners using as a model the primitively eusocial wasp Polistes dominula in which female caste is rather flexible and difficult to determine. By means of laboratory bioassays, we compared the males' behaviour towards females of different reproductive potential. Males were able to recognize female castes, strongly preferring reproductive females to workers, regardless of female age or health. The results show that in this species caste plays a key role in orienting male discrimination and preference, presumably through chemical cues, towards reproductive females both healthy and parasite-castrated. Overall, our study shows that social Hymenoptera males are not always ‘small mating machines’ eager to mate.

Although sexually selected ornaments are common across diverse taxa, little is known about mate choice and sexually selected ornamentation in social insects. Polistes dominulus paper wasps are a good system to study sexual selection, as males have a lek-based mating system as well as sexually dimorphic abdominal spots. Here, we demonstrate that the abdominal spots of male P. dominulus paper wasps function as signals in both inter- and intrasexual selection. Males with smaller, elliptically shaped spots were more dominant over male rivals and were more preferred by females than males with larger, irregularly shaped spots. Furthermore, experimental manipulation of male spots demonstrates that spot morphology acts as a signal. Males with experimentally reduced abdominal spots won a greater proportion of fights and were preferred by females as mates over control males. These results demonstrate that male ornaments are an important mediator of mating dynamics in P. dominulus paper wasps. They also highlight the importance of additional research examining sexually selected ornamentation in social insects.

Within-group power asymmetries and the resulting reproductive skew, common in most social groups, may effectively be set at the very early stages of group formation, that is, when group membership is determined. Hence, groupmate choices can define an individual’s future reproductive success. We examined how groups of Polistes dominulus formed under natural, unconstrained conditions, using data on the nesting history, kinship and morphology of individually marked foundresses obtained during two consecutive seasons in southern Spain. Foundresses that hibernated in the same aggregation were more likely to start a nest together, but all of the foundresses at a nest were seldom from a single aggregation. Changes in group composition were frequent throughout the preworker period, mainly because some foundresses disappeared and other wasps joined established groups. Within-group relatedness, however, was not affected by the late arrival of wasps. Our results suggest that waiting to join an established group is a common nesting strategy in P. dominulu s. Only 16% of marked wasps used more than one nest. Foundresses that moved between groups tended to move to groups in which genetic relatedness among the resident foundresses was higher, but not necessarily relatedness to the moving wasp herself. Overall, nestmate choices were not associated with a single factor. High failure rates, particularly of single-foundress nests, however, suggest that ecological constraints (e.g. risk of predation, lack of resources) may have a stronger effect on individual nesting choices than previously considered.

Insect social parasites need to overcome host colonies’ defences to exploit their resources successfully. Sophisticated sensory deception mechanisms to break the host’s barriers have been repeatedly reported for many social parasites, possibly concealing the importance of open fighting, a more ancestral strategy. Understanding the relative importance of fooling and fighting is primarily challenging when the two strategies seem both available and advantageous. We focused on the paper wasp social parasite–host system Polistes sulcifer–P. dominulus , where both fooling and fighting have been suggested to play a role during usurpation contests. Host aggression is elicited by the chemical cues (hydrocarbons) that intruders bear on their cuticle. Parasites would benefit from reducing the amount of these cues before approaching the host colony. In addition, the parasites’ facial pattern has been shown to reduce the host’s aggressive reaction, probably by amplifying the mandibular width. We tested the occurrence of chemical and visual cheating through chemical analyses and laboratory usurpation trials, respectively. Usurping parasites did not conceal their identity by reducing cuticular hydrocarbons, nor did their facial pattern facilitate nest take-over. Contest outcome was instead predicted by the relative body size of the opponents. Fighting, rather than fooling, is therefore the strategy used by P. sulcifer usurping females. The importance of physical strength could thus explain why chemical or visual tricks do not play a role in taking over the host colony despite their potential usefulness. Our findings suggest that the evolution of sophisticated cheating mechanisms can be prevented by the ability to fight.

Contests between individuals over resources may be costly in terms of both time and energy expended and the risk of injury. Signals of status, or ‘status badges’, are thought to have evolved to minimize these costs by providing information about an individual’s fighting ability or resource-holding potential (RHP) at the start of a contest. Studies on recently established North American populations of the paper wasp Polistes dominulus have demonstrated the existence of a status badge, in the form of black clypeal patterns, and have shown that rivals attend to these patterns during competitive interactions. However, observational data from studies in this wasp’s native European range have failed to demonstrate a strong link between clypeal patterning and RHP. We undertook the first direct test of status signalling in a European population of P. dominulus, by testing receiver responses to clypeal pattern manipulations in a competitive foraging context. We found no evidence that individuals assessed rivals using the clypeal ‘badge’. We discuss possible reasons for variation in signal use between the American and European populations, including genetic drift and environmental effects of the development and transmission of the signal.

Obligate social parasite insects are specialized in exploiting the parental service of the workers of another social species by invading their colonies. As social insects are usually aggressive towards intruders, social parasites have to circumvent the host’s nestmate recognition system to enter the host colony successfully. Many studies on paper wasps have shown that, after host nest invasion, Polistes social parasites change their chemical profile to match the host’s odour, thus allowing their acceptance into its colony. However, a social parasite’s usurpation strategy may benefit from signals that reduce or eliminate the aggression of the host. We used lure presentation experiments to investigate whether Polistes sulcifer , a social parasite of the paper wasp P. dominulus , is able to reduce the aggressive reaction of its host. We found that the parasite lure elicited lower host aggressiveness than the conspecific lure, suggesting that parasite species have evolved cues able to inhibit host aggressiveness. We investigated separately the effects of chemical and visual patterns on host aggressiveness. The lower host reaction to the parasite lure was not due to chemical cues, but was elicited by the visual facial pattern of the parasite. Experimental manipulation of this visual pattern demonstrated that the black lower part of the clypeus of the parasite is the trait able to reduce host aggression. This pattern can be considered an honest signal since it visually amplifies the mandibular width, giving information about the parasite’s dangerousness.

The ecological constraints model (ECM) was formulated to predict how different ecological factors affect cooperative-breeding vertebrates. Within these groups some individuals help raise nondescendent young because of constraints that limit their own reproduction (e.g. limited foods, reproductive opportunities and nesting sites). Despite similarities between cooperative-breeding vertebrates and facultatively social insects, few studies have explicitly and experimentally determined how the ECM applies to social insects. In this study, we examined the potential effects of predation, density and nest site limitation as well as differences in nest site quality on the alternative nesting tactics of the paper wasp Mischocyttarus mexicanus. Accurate field estimates of density were possible because multiple nests are initiated in isolated Sabal palmetto trees. Results from a 17-month census showed more solitary nesting when density was low and nest sites were plentiful. In addition, females appeared to prefer nests initiated on unoccupied east-facing fronds. We then examined the potential effect of density and nest site limitation in a field experiment by adding or removing fronds from S. palmetto and forcing all females to renest. The percentage of haplometrotic females decreased when fronds were removed (increased density treatment), increased when fronds were added (decreased density treatment), and showed a mixed response when frond number remained unchanged (control density treatment). Nest site limitation did not appear to affect renesting females: the percentage of available unoccupied fronds was not affected by treatment. Mischocyttarus mexicanus females responded primarily to their social environment within palm groves and to variation in nest site quality, instead of constraints that typically affect cooperative-breeding vertebrates.

Female Polistes paper wasps can initiate colonies either solitarily or in cooperative groups. Reproduction is often distributed unequally in groups, even to the point of complete monopolization of breeding by the dominant group member. Transactional models of reproductive skew predict the degree of reproductive partitioning, assuming that the dominant controls group membership and will yield a proportion of reproduction to a subordinate as an incentive to stay peacefully in the group. Using a combination of demographic, genetic and morphological data from a population of P. dominulus, we test predictions of ‘classical’ two-person skew models as well as more complex ‘N-person’ models. This is the most comprehensive study of skew in this species to date, and the results generally do not support transactional models. We found no relationship between skew and relatedness for dyads, and complete skew was observed in unrelated groups despite the prediction for this population that such groups should not occur. In contrast to N-person model predictions, group size tended to increase with relatedness. Although we did find the predicted positive correlation between group size and skew for groups of nonrelatives, this relationship was weak. The zone of conflict between the predicted minimum and maximum staying incentives often spans the entire possible range of reproductive skew, suggesting that a ‘tug-of-war’ scenario may be more appropriate than a transactional framework for understanding within-colony dynamics. Overall, our results demonstrate that transactional skew models have little predictive power and are therefore unlikely to yield further insight into Polistes wasp societies.

Communicative interactions between colony members, or worker connectivity, can affect division of labour in insect societies. Nestmate workers of the eusocial paper wasp Polybia occidentalis engage in biting interactions, and correlational evidence suggests that biting promotes foraging by the workers that are bitten. I used experimental forager removals to test whether biting is a form of worker connectivity, inducing new recruits to enter the foraging force. I observed colonies with marked workers during a pretreatment (control) period, then removed all arriving foragers on the following day. Foraging ceased after several hours of forager removals, and remained depressed on the following morning. I grouped the remaining workers into four behavioural categories: nonforagers, individuals that stopped foraging after the manipulation, continuing foragers that were active before and after the manipulation and recruited foragers that began foraging after the manipulation. After the manipulation, the recruited foragers were bitten at similar rates to the continuing foragers and, most importantly, were the only ones that were bitten at significantly increased rates after the manipulation. Most recruits were observed being bitten before they began foraging. However, some recruits were not observed being bitten, and worker responses to biting were often gradual. These patterns suggest that the effect of biting is to modulate the probability of foraging in bitten workers. The experiments show that biting helps to induce foraging. Biting is a form of worker connectivity, serving as a mechanism of communication between Polybia workers that affects colony responses to changing conditions.

In social insects, workers stay in their natal nests and help to rear their siblings, rather than founding independent nests. In three field experiments, we investigated the factors influencing the decision of workers of the paper wasp Polistes chinensis antennalis to stay in their natal nest. We divided nests of P. chinensis antennalis in half and placed each half separately in the field. Workers were then allowed to choose one of the halves, one of which had a queen and the other did not. Workers initially visited both halves, but later visited only one. When both half-nests contained brood, they were maintained by a group of wasps as two independent colonies, even though one had no queen. In addition, the initial presence of workers in the nests did not affect which nests were maintained. When one half-nest contained brood and the other did not, only the half with brood was maintained. This result is consistent with the ‘life insurance advantage’ hypothesis for the evolution of eusociality.

e present evidence that nestmate discrimination in the eusocial paper wasp, Polistes dominulus, is context dependent. We compared aggression levels between nestmates and non-nestmates in dyads consisting of a pair of either nestmates or non-nestmates, and triads consisting of either three nestmates, three non-nestmates, or two nestmates and a non-nestmate. In 130 of the 237 total trials, a nest fragment (containing both brood and eggs) from the nest of some, all or none of the interactants was placed into the interaction arena. Polistes dominulus workers recognized and discriminated nestmates from non-nestmates, familiar from unfamiliar nest material and neighbours from non-neighbours. These findings suggest that nestmate and neighbour discrimination are context dependent: discrimination occurs when either the presence of a nestmate or a familiar nest fragment indicate the proximity of the colony. The context-dependent variation in aggression levels is best described by multiple, context-dependent shifts in an acceptance threshold. Thus this study provides the most extensive, critical support yet obtained for Reeve's (1989, American Naturalist, 133, 407-435) optimal acceptance threshold model. Copyright 1998 The Association for the Study of Animal Behaviour

The paper wasp, Polistes fuscatus , builds its nest by both linear and non-linear construction. Linear construction follows a set sequence of building acts, while non-linear construction can be performed with any of several building acts at a given time. We report on the building programme regulating the non-linear phase of construction and discuss its relevance to the construction behaviour of other species. New cell placement is influenced by distance to the substrate, the location of nearest-neighbour cells (older cells on which the new cell is initiated), the groove between nearest-neighbour cells, orientation of comb and gravity. Gravity also influences many aspects of cell shape, and more cells tend to be added to the lower side of a tilted comb. Amputating one-half of one antenna from wasps demonstrated that the antennae are used for many of the measurements required during construction. Cell lengthening is initially done at a constant rate. Once the larvae become third instars, however, cell lengthening is regulated by larval growth. Wasps use two methods to repair holes in a cell wall: (1) patching and (2) tearing down the wall and rebuilding it. The time to repair decreases with subsequent holes, and some wasps clearly show an improvement in repair technique with experience, suggesting that some learning is involved. The cues triggering the addition of pulp to the petiole, the substrate and the pupal caps and secondary petiole construction were also investigated. These activities are infrequently performed and only specific cues could induce some of them. The decision process involved in non-linear construction can be represented by a non-overlapping branching hierarchy of choice levels. At each construction choice level, multiple cues are evaluated either simultaneously or in a hierarchical manner. Evidently, the more complex nest construction becomes (non-linear construction, multiple building materials, etc.), the more sophisticated the building programme must be. Hierarchical levels of evaluation, sub-routines within the building programme, and learning capabilities appear to be ways of achieving this sophistication.

In this study I examined how the paper wasp, Polistes fuscatus, defends a colony when faced with a vertebrate attack. I looked for a division of labour in defensive behaviour within a colony and examined whether this behaviour changes over the colony cycle. The colonies were presented with a model of an adult red-winged blackbird, Agelaius phoeniceus, and a speaker that vibrated the comb. There was a pronounced division of labour in the defence against vertebrate predators within a colony. The queen was consistently the most aggressive individual in the colony. The subordinate foundresses and workers both became more aggressive towards a vertebrate predator as they aged. Gynes and males did not participate in colony defence. The level of aggression in colony members of P. fuscatus appears to be related to the reproductive investment of the colony. Copyright 2000 The Association for the Study of Animal Behaviour.

We investigated the mechanism of worker kin discrimination in the paper wasp, Polistes fuscatus, using workers reared by unrelated foundresses. Nests containing worker-destined larvae were switched between unrelated foundresses before worker eclosion. Subsequently eclosing workers were isolated for 20 days and then placed together in triplets of two sisters and a non-sister. Workers can discriminate sisters from non-sisters without previous exposure as adults to adult kin. Sibling discrimination depends upon cues, presumably odours, that are learned at the natal nest.

The water collection behaviour of colony foundresses of a Japanese paper wasp, Polistes chinensis antennalis , was recorded. A single round-trip of water collection consists of (1) an outward flight, (2) water-sucking, and (3) a homeward flight. The rate of water intake decreased as the length of water-sucking increased. There was a positive correlation between the duration of the outward flight and that of water-sucking. The variance of time for outward flights was larger than that for homeward flights. The data were consistent with the predictions of the central place foraging model of Orians & Pearson (1979) .

The paper wasp, Polistes fuscatus , begins building its nest by a linear series of construction steps. Once the first cell is initiated, the building becomes more complex in that any one of several construction acts may be done at any given time. The cues controlling construction during the initial linear series of steps were investigated. The building programme of this wasp was then compared to stigmergy theory, a model of linear construction behaviour which holds that ongoing construction is regulated by previous construction. As predicted by stigmery theory, P. fuscatus uses certain features of already completed construction to provide the cues for subsequent construction. Contrary to predictions from the theory, however, this wasp uses other additional types of cues and evaluates some of the same nest features at each step of construction. Thus, this wasp is able to analyse many different aspects of its nest at one time to determine the correct building sequence and methods, a process more complex than that proposed by stigmergy theory.

Mechanisms of initial orientation in females of the social paper wasp Polistes gallicus (L.) were studied by releasing them 50 m away from their nest inside an arena and at a distance of 1000 m in the open, after displacing the wasps by four different methods. Results indicate that (1) the accuracy of initial orientation depends on visual information acquired during displacement, (2) this information consists of perceiving the direction of visual flow during passive displacement, and does not depend on the recognition of familiar landmarks, (3) the direction of visual flow is measured relative to a sky compass. The supplementary angle with a celestial reference point at the moment of release would give the wasp the reverse direction for the return flight home.