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Paper wasps negotiate over help using indicators of demand. Animal societies are composed of individuals whose genetic interests are often opposed. We conducted experiments on a cooperative paper wasp which reveal the behavioural rules by which group members settle these conflicts.Recent theory and empirical studies of avian biparental systems suggest that animals resolve conflict over parental care via a process of behavioral negotiation or “rules for responding.” Less is known, however, about whether negotiation over helping effort occurs in cooperatively breeding animal societies or whether behavioral negotiation requires a relatively large brain. In this study, we tested whether negotiation over help occurs in a social insect, the paper wasp Polistes dominulus, by recording individual responses to both observed and experimentally induced foraging returns by other group members. In our experiments, we manipulated food delivery to the nest in 2 ways: 1) by catching departing foragers and giving them larval food to take back to the nest and 2) by giving larval food directly to wasps on the nest, which they then fed to larvae, so increasing food delivery independently of helper effort. We found no evidence from Experiment 1 that helpers adjusted their own foraging effort according to the foraging effort of other group members. However, when food was provided directly to the nest, wasps did respond by reducing their own foraging effort. One interpretation of this result is that paper wasp helpers adjust their helping effort according to the level of offspring need rather than the work rate of other helpers. Negotiation based on indicators of demand rather than work rate is a likely mechanism to resolve conflict over investment in teams where helpers cannot observe each other’s work rate directly, as is commonly the case in insect and vertebrate societies. [ABSTRACT FROM PUBLISHER]

Theory on animal contests often assumes that individuals can rapidly and accurately assess their own resource-holding potential (RHP). In empirical work, individuals behave as if they ‘know’ their own RHP, but little is known about how such assessment occurs. Here, we test how juvenile hormone (JH) influences precontest behaviour in P. dominulus paper wasps. Previous work has shown that P. dominulus have variable black facial patterns that are a signal of agonistic ability and that JH influences fighting ability. In this experiment, we tested how JH influences rival challenge behaviour in the absence of direct social competition. Wasps were given the opportunity to challenge or avoid a model wasp guarding a patch of food. Individuals treated with the JH analogue methoprene were more likely to challenge rivals than were control individuals, and they also had a shorter latency to challenge than controls. However, hormone treatment was only one of multiple factors that influenced behaviour, suggesting that assessment prior to contests is based on the interplay between individual physiology and social context. Contest decisions were also dependent on a wasp's own facial pattern and mass, as well as the facial pattern of its rival. Interestingly, these complex assessment decisions occurred in the absence of direct social cues that could be acquired during a contest. These results are consistent with JH playing a role in self-assessment of RHP. Hormones such as JH are influenced by the physical and social environment, so they provide diverse information about relative RHP and may be commonly involved in assessment behaviour. [ABSTRACT FROM AUTHOR]

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. [Copyright &y& Elsevier]

Foundresses and workers of Polistes paper wasps show slight morphological and physiological differences. However, after the emergence of the workers, the castes can be readily discriminated by their behaviour: the dominant foundress is the principal egg-layer, whereas workers perform different tasks linked to colony development. Previous studies have demonstrated in this genus that defence of the colony by the workers is more effectively carried out by a collective response elicited by venom volatiles used as alarm pheromones. In the present study, gas chromatography-mass spectrometry analyses of the venom volatiles of foundresses and workers of Polistes dominulus (Christ) show predominantly quantitative differences. Spiroacetals, mainly (E,E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane, are significantly higher in the venom volatiles fraction of workers, whereas the amount of N-(3-methylbutyl)acetamide is almost double in foundresses. On the basis of the chemical results, behavioural assays were performed on fifteen field colonies to test the alarm response of the resident wasps to venom extracts from foundresses and workers. Our behavioural results suggest that worker venom has a stronger alarm effect on the colonies than that of the foundresses, which seems unable to elicit the complete alarm response ending with a final attack and sting. The venom volatiles of P. dominulus workers serve mainly to alarm the colony whilst those of foundresses may also be linked to additional functions related to conspecific interactions. [ABSTRACT FROM AUTHOR]