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Social insects have developed different nest defence strategies; for example, social wasps use nonaggressive mechanisms or aggressiveness, including stinging. This subject has been widely examined in the literature, and it may help improve our understanding of wasps' ecology. The nesting behaviour of some genera is still poorly known. In this paper, we report new information on the nesting behaviour of the species Clypearia in different Brazilian biomes. We observed six nesting events in natural and anthropic environments of the Amazon rainforest, Atlantic forest, and Cerrado domains, sporadically from 2004 to 2022. From our observations, we suggest that Clypearia nest defence includes (i) preference for nest camouflage rather than aggressive behaviour; (ii) selection of nesting sites close to water sources in natural or anthropic environments, and eventually obtaining food from the substrate; (iii) nesting association with ants for mutual protection against predators; and (iv) variations in the nests' height. Our records suggest nest camouflage and association with ants are strategies for nest defence. These may have influenced nest height in relation to the ground, which may also vary according to the environment explored by the species. [ABSTRACT FROM AUTHOR]

Overwintering insects are facing energetic challenges because of food shortage, low temperature, and desiccation stress. Paper wasps of the genus Polistes overwinter as mated adults (gynes) in hibernacula protecting them from predation, snow, and rain but barely from low environmental temperature. In different climates, they face differing overwintering temperature regimes, and therefore they may differ in their energy use. We investigated how much of energy resources built up until autumn is used during diapause dormancy in natural hibernacula by measuring lipid, glycogen, and free carbohydrate content in autumn and early spring in Polistes dominula from temperate European (Austrian) and warm Mediterranean (Italian) climate and Polistes gallicus from Mediterranean climate. Winter energy consumption amounted to ~ 339 and ~ 310 J per wasp in the Austrian and Italian Polistes dominula populations. The smaller Italian Polistes gallicus consumed ~ 247 J. This amounts to 2.62, 2.35, and 1.79 J per day. Of this, the energy demand was mainly fuelled by lipids (84%, 93%, and 90%, respectively), but glycogen stores contributed also considerably (16%, 6%, and 9%). Free carbohydrates decreased only by 0.7%, 1%, and 0.8%. While fat stores seem still sufficient in spring, the wasps depleted most of their carbohydrates. The energy reserves of 396, 400, and 147 J per wasp remaining in spring in the three populations seem sufficient to fuel rest or simple brood care activities for a whole summer but restrict foraging flights to a few hours (~ 3.5–6 h). Results suggest that energy supply might become challenging in expected future climate scenarios. [ABSTRACT FROM AUTHOR]

Mitochondrial (mtDNA) genes have served as widely utilised genetic loci for phylogenetic and phylogeographic studies of animals. However, the phylogenetic performance of many mtDNA genes has not been empirically evaluated across lineages within hymenopteran wasps. To address this question, we assembled and analysed mitogenomic data from social wasps, representing the four recognised tribes of Polistinae and all Epiponini genera. Additionally, we evaluated whether mtDNA gene order in Polistinae is congruent with its tribal classification. Using concatenation phylogenetic methods, we show phylogenetic congruence between mitogenomic and nuclear data. Statistically comparing the phylogenetic performance of individual mtDNA genes, we demonstrate that for social wasps the molecular markers COI, 16S, NAD5, and NAD2 perform best, while ATP6, COII, and 12S show the worst results. Finally, we verified that the tRNA cluster close to the noncoding region is a hotspot of genetic rearrangements in Vespidae and can be used as additional information for the systematics of this group. Together, these results indicate that mitogenomes contain robust phylogenetic signal to elucidate the evolutionary history of Vespidae. Moreover, our study identifies the best choice of mtDNA markers for systematic investigations of social wasps. [ABSTRACT FROM AUTHOR]

Specific Venom Immunotherapy (VIT) is practiced with venom extracted from insects, and is the specific therapy used for patients highly allergic to social insect (Hymenoptera) stings. Due to the dramatic shortage of vespid species in the local environment, we coupled vespiculture techniques of Polistes paper wasps with a venom collection procedure based on the electrical stimulation of individuals from entire colonies. The procedure involves little to no disturbance of the individual insects, and at the same time, successfully allows for the extraction of venom containing all allergens necessary for VIT. [ABSTRACT FROM AUTHOR]

Honey is a healing compound produced by the Apidae bees. So far, the only genus of Apis with 9 known species worldwide is a honey bee. But species of paper wasps in the Vespidae can also produce honey. This research was conducted to study and identify the species of paper wasp honey producer in the South of Kerman. For this purpose, the activity areas of this wasp were identified, and specimens of this paper wasp were collected for species identification. The specimens were identified by keys and related articles and Confirmed by Dr. James M. Carpenter at the American Museum of natural history. Parapolybia escalerae (Meado-Waldo) was described by Mead-Waldo in the London British Museum in 1911 as a single female specimen from southwestern Iran. The World distribution of this paper wasp is in Pakistan, Turkey, and Iran. According to the results of this study, the species Parapolybia escalerae (Meado-Waldo, 1911) was identified for the first time in southeastern Iran (south of Kerman). This species was distributed south of Kerman from the tropical foothills of Jabalbarz Mountains (southern Jabalbarz to Mohammadabad) and Bahraseman. Parapolybia escalerae is introduced in the world as a paper wasp species of a honey producer. The paper wasp is known as dry or chocolate honey and has medicinal use. In this study, the male and queen specimens were collected and identified for the first time. This study found that this species of paper wasp, like the Apis florea, produces wild honey. A. florea has open nests and small colonies of a single comb, but P. escalerae is in the dark space of mountains and cliffs and produces many combs. The activity of this species was mostly observed on the Ziziphus sp. and Pistacia terebinthus trees. This paper wasp has a social life and includes three forms of queens, workers, and males. So far, only two species of Honey producing paper wasps have been reported in South America, including Brachygastra mellifica (Say, 1837), known as the Mexican Honey Wasp and Brachygastra lecheguana (Latreille, 1824), which are paper wasps belonging to the subfamily Polistinae. These two species have round nests and build their nests on tall trees and the ground in open spaces. Their honey has medicinal use in different regions of South America and is collected by local people. The paper wasp species P. escalerae works in the crevices of the rocks and has several flat combs. In Iran, the local people of the southern regions of Iran use this honey as medicine to treat respiratory diseases. [ABSTRACT FROM AUTHOR]

The genus Latibulus Gistel, 1848 (Hymenoptera: Ichneumonidae) is taxonomically reviewed in Iran. Specimens were collected using Malaise traps in the Isfahan province, during 2013–2015. Two species, Latibulus argiolus (Rossi, 1790) (spring form) and Latibulus orientalis (Horstmann, 1987) (summer form) are identified, of which L. orientalis is a new record for the fauna of Iran. In addition, L. argiolus is recorded from central part of Iran (Isfahan) for the first time. The geographical distribution of the recorded species in relation to the overall knowledge in the target area and adjacent regions is also discussed.

231 species of the family Vespidae (Hymenoptera, Vespoidea) of Iran, in 55 genera belonging to 4 subfamilies Eumeninae (45 genera, 184 species), Masarinae (5 genera, 24 species), Polistinae (2 genera, 17 species) and Vespinae (3 genera, 6 species) are listed. An overall assessment of the distribution pattern of the vespid species in Iran indicates a complex fauna of different biogeographic regions. 111 species are found in both Eastern and Western Palaearctic regions, while 67 species were found only in the Eastern Palaearctic region. Few species (14 species – 6.1%) of various genera are known as elements of central and western Asian area and their area of distribution is not known in Europe (West Palaearctic) and in the Far East. The species that were found both in the Oriental and Afrotropical Regions comprises 11.7 and 15.6% the Iranian vespid fauna, respectively. Many species (48, 20.8%) are exclusively recorded from Iran and as yet there is no record of these species from other countries. The highest percentage of the vespid species are recorded from Sistan-o Baluchestan (42 species, 18.2%), Alborz (42 species, 18.2%), Fars (39 species, 16.9%) and Tehran provinces (38 Species 16.5%), representing the fauna of the Southeastern, North- and South Central of the country.

Specific Venom Immunotherapy (VIT) is practiced with venom extracted from insects, and is the specific therapy used for patients highly allergic to social insect (Hymenoptera) stings. Due to the dramatic shortage of vespid species in the local environment, we coupled vespiculture techniques of Polistes paper wasps with a venom collection procedure based on the electrical stimulation of individuals from entire colonies. The procedure involves little to no disturbance of the individual insects, and at the same time, successfully allows for the extraction of venom containing all allergens necessary for VIT.

Sexual pheromones are chemical molecules responsible for mediating sex recognition and mating events. Long- and close-range sexual pheromones act differently. The first type is released to attract potential partners, whereas the second coordinates the interactions after potential mating partners encounter each other. Cuticular hydrocarbons (CHCs) have been suggested to be important cues in the mating systems of several Hymenoptera species, although empirical data are still lacking for many species. Here, we evaluated whether males of the model species Polistes dominula can differentiate the sex of individuals based on their CHC composition. In August 2019, several post-worker emergent nests (n = 19) were collected in the vicinity of Leuven (Belgium) and taken to the lab (KU Leuven), where newly emerged females and males were sampled, marked individually, and kept in plastic boxes for at least a week before being used in the mating trials. Focal males were paired with females and males from different nests and subjected to five different conditions: (I) alive, (II) dead, (III) CHCs washed, (IV) CHCs partially returned, and (V) CHCs from the opposite sex. We videotaped the interactions for 10 min and analysed the duration and different behavioural interactions of the focal male. Our results indicate that CHCs may be used by males as cues to recognise a potential mating partner in P. dominula, since the focal males displayed specific courtship behaviours exclusively toward females. Although we cannot exclude that visual cues could also be used in combination with the chemical ones, we empirically demonstrate that CHCs may be important to convey sexual information at close range in mating systems, allowing fast decisions toward potential sexual partners or rivals. [ABSTRACT FROM AUTHOR]

The yellow paper wasp, Polistes versicolor (Olivier) was first recorded in the Galapagos archipelago in 1988. Its life cycle and ecological impacts were studied on two islands 11 yr after it was first discovered. This invasive wasp adapted quickly and was found in most environments. Colony counts and adult wasp monitoring showed a strong preference for drier habitats. Nest activities were seasonally synchronized, nest building followed the rains in the hot season (typically January–May), when insect prey increases, and peaked as temperature and rains started to decline. Next, the number of adult wasps peaked during the cool season when there is barely any rain in the drier zones. In Galapagos, almost half of the prey loads of P. versicolor were lepidopteran larvae, but wasps also carried spiders, beetles, and flies back to the colonies. An estimated average of 329 mg of fresh insect prey was consumed per day for an average colony of 120–150 wasp larvae. The wasps preyed upon native and introduced insects, but likely also affect insectivorous vertebrates as competitors for food. Wasps may also compete with native pollinators as they regularly visited flowers to collect nectar, and have been recorded visiting at least 93 plant species in Galapagos, including 66 endemic and native plants. Colonies were attacked by a predatory moth, Taygete sphecophila (Meyrick) (Lepidoptera: Autostichidae), but colony development was not arrested. High wasp numbers also affect the activities of residents and tourists. A management program for this invasive species in the archipelago is essential. [ABSTRACT FROM AUTHOR]

Refurbishing the old nest in order to prepare it for a new breeding season cycle has already been observed in few species of paper wasps. When future foundresses emerge from hibernacula they have choose between building a new nest or reusing an old one. In present paper I described a case of multiple use and further expansion an old nest by Polistes dominula (Christ, 1791) in Grodzisk Mazowiecki, Mazovia Region, Central Poland.

The aim of the study was to determine the extent of heavy metal accumulation (Zn, Cd and Pb) in the bodies of females of the predatory species Polistes nimphus (Christ, 1791) (Hymenoptera, Vespidae). The insects were captured in areas affected by the proximity of ZGH "Bolesław" - an industrial complex located in Bukowno near Olkusz (southern Poland), whose main activity is mining and processing of lead and zinc ores. Three sites that differed in terms of distance from the source of contamination and also in the concentrations of Zn, Cd and Pb in the top soil layer were selected. The heavy metal content of the soil was determined for each site. The most contaminated site was located in the immediate vicinity of ZGH "Bolesław" (4326.50 mg/kg Zn, 56.96 mg/kg Cd, 3977.00 mg/kg Pb); the least contaminated was the site furthest away from the source of contamination (48.75 mg/kg Zn, 0.72 mg/kg Cd, 25.43 mg/kg Pb). On all the sites, during the two-year study (2015-2016), individuals of the genus Polistes were captured and female wasps of the species P. nimphus were isolated from among them. Then the extent of accumulation of Zn, Cd and Pb in their bodies was determined. Correlations between the concentrations of Cd, Zn and Pb in the soil and those in insect bodies were calculated. On all three sites, in both years of the study, the concentrations of heavy metals in insect bodies changed depending on their concentrations in the soil. The highest levels of the accumulated Zn, Cd and Pb were always observed on the site located in the vicinity of ZGH "Bolesław". The lowest values were observed on the site furthest away from the source of contamination. The concentrations of all three metals in the bodies of insects increased with their increasing concentrations in the soil, but the differences were not statistically significant. [ABSTRACT FROM AUTHOR]

Invasive species can be particularly disruptive when they intersect with organisms of conservation concern. Stabilizing the declining eastern migratory population of monarch butterflies (Danaus plexippus) is projected to require extensive habitat restoration across multiple land use sectors including metropolitan areas. Numerous conservation programs encourage urban citizens to plant gardens with milkweeds, the obligate larval host plants of the monarch. Here, we show that predation by Polistes dominula, an invasive paper wasp that is particularly abundant in urban settings, can turn such sites into ecological traps for monarch larvae. Polistes dominula was the predominant paper wasp seen foraging in central Kentucky pollinator gardens. In 120 observed encounters with monarch larvae on milkweeds in gardens, most second to fourth instars were killed, whereas most fifth instars escaped by thrashing or dropping. The wasps bit and carried off second instars whole, whereas third and fourth instar kills were first gutted, then processed and carried away piecemeal. Predation on sentinel larvae was much higher in urban gardens than in rural settings. The wasps exploited ornamental butterfly "hibernation boxes" in pollinator gardens as nesting habitat. Polistes dominula is an under-recognized predator that may diminish the urban sector's contributions to monarch habitat restoration. [ABSTRACT FROM AUTHOR]

The Neotropical realm harbours unparalleled species richness and hence has challenged biologists to explain the cause of its high biotic diversity. Empirical studies to shed light on the processes underlying biological diversification in the Neotropics are focused mainly on vertebrates and plants, with little attention to the hyperdiverse insect fauna. Here, we use phylogenomic data from ultraconserved element (UCE) loci to reconstruct for the first time the evolutionary history of Neotropical swarm-founding social wasps (Hymenoptera, Vespidae, Epiponini). Using maximum likelihood, Bayesian, and species tree approaches we recovered a highly resolved phylogeny for epiponine wasps. Additionally, we estimated divergence dates, diversification rates, and the biogeographic history for these insects in order to test whether the group followed a 'museum' (speciation events occurred gradually over many millions of years) or 'cradle' (lineages evolved rapidly over a short time period) model of diversification. The origin of many genera and all sampled extant Epiponini species occurred during the Miocene and Plio-Pleistocene. Moreover, we detected no major shifts in the estimated diversification rate during the evolutionary history of Epiponini, suggesting a relatively gradual accumulation of lineages with low extinction rates. Several lines of evidence suggest that the Amazonian region played a major role in the evolution of Epiponini wasps. This spatio-temporal diversification pattern, most likely concurrent with climatic and landscape changes in the Neotropics during the Miocene and Pliocene, establishes the Amazonian region as the major source of Neotropical swarm-founding social wasp diversity. [ABSTRACT FROM AUTHOR]

Evolutionary transitions in social behavior are often associated with changes in species' brain architecture. A recent comparative analysis showed that the structure of brains of wasps in the family Vespidae differed between solitary and social species: the mushroom bodies, a major integrative brain region, were larger relative to brain size in the solitary species. However, the earlier study did not account for body size effects, and species' relative mushroom body size increases with body size in social Vespidae. Here we extend the previous analysis by measuring the effects of body size variation on brain structure differences between social and solitary vespid wasps. We asked whether total brain volume was greater relative to body size in the solitary species, and whether relative mushroom body size was greater in solitary species, after accounting for body size effects. Both total brain volume and relative mushroom body volume were significantly greater in the solitary species after accounting for body size differences. Therefore, body size allometry did not explain the solitary versus social species differences in brain structure. The evolutionary transition from solitary to social behavior in Vespidae was accompanied by decreases in total brain size and in relative mushroom body size. [ABSTRACT FROM AUTHOR]

Social parasites have evolved adaptations to overcome host resistance as they infiltrate host colonies and establish there. Among the chemical adaptations, a few species are chemically “insignificant”; they are poor in recognition cues (cuticular hydrocarbons) and evade host detection. As cuticular hydrocarbons also serve a waterproofing function, chemical insignificance is beneficial as it protects parasites from being detected but is potentially harmful because it exposes parasites to desiccation stress. Here I tested whether the social parasites Polistes atrimandibularis employ behavioral water-saving strategies when they live at Polistes biglumis colonies. Observations in the field showed that parasites were less active than their cohabiting host foundresses, spent more time at the nest, and rested in the shadowy, back face of the nest, rather than at the front face, which contradicted expectations for the use of space for dominant females—typically, dominants rest at the nest front-face. These data suggest that behavioral adaptations might promote resistance to desiccation stress in chemical insignificant social parasites.

The social vespid wasps (Hymenoptera: Vespidae: Vespinae and Polistinae) was studied in Bhutan during 2014-2016. A total of fifteen species were collected and identified that all of them are reported as new records from Bhutan: Vespa vivax Smith, V. velutina variana van der Vecht, V. fumida van der Vecht, Dolichovespula lama (du Buysson), Vespula flaviceps Smith, V. nursei Archer, V. vulgaris (Linnaeus), V. structor (Smith), Polistes (Polistella) nigritarsus (Cameron), Parapolybia varia (Fabricius), P. nodosa van der Vecht, Ropalidia artifex (de Saussure), R. stigma (Smith), R. ornaticeps (Cameron) and R. rufoplagiata gravelyi (Dover & Rao). Diagnostic characters and geographical distribution of all species are presented.

Nestmate recognition, i.e., the ability to discriminate nestmates from foreign individuals, is a crucial feature of insect societies, and it has been traditionally considered to be predominantly based on chemical cues. Recent empirical evidence, however, suggests a relevant plasticity in the use of different communication channels according to cue availability and reliability in different contexts. In particular, visual cues have been shown to influence various types of social recognition in several social insects, but their role in nestmate recognition is still under-investigated. We tested the hypothesis of plasticity in the use of visual and chemical recognition cues in the primitively eusocial wasp Polistes dominula, in which the availability and reliability of recognition cues vary across the colony cycle. Indeed, before the emergence of workers, P. dominula colonies are rather small (one to few individuals), and the variability in the facial pattern might allow resident wasps to use visual cues for nestmate recognition. After workers' emergence, the increase in the number of colony members reduces the reliability of visual cues, thus leaving chemical cues as the most reliable nestmate recognition cues. We thus predict a differential use of chemical and visual cues along colony life. We experimentally separated visual and chemical cues of nestmates and non-nestmates and presented them alone or in combination (with coherent or mismatched cues) to resident wasps to test which communication channel was used in the two stages and, in case, how visual and chemical cues interacted. Our results show, for the first time in a social insect, the differential use of visual and chemical cues for nestmate recognition in two different phases of colony, which supports the hypothesis of a plastic, reliability-based use of recognition cues in this species according to the different colonial contexts.

Biocontrol agents can help reduce pest populations as part of an integrated pest management scheme, with minimal environmental consequences. However, biocontrol agents are often non-native species and require significant infrastructure; overuse of single agents results in pest resistance. Native biocontrol agents are urgently required for more sustainable multi-faceted approaches to pest management. Social wasps are natural predators of lepidopteran pests, yet their viability as native biocontrol agents is largely unknown. Here, we provide evidence that the social paper wasp Polistes satan is a successful predator on the larvae of two economically important and resilient crop pests, the sugarcane borer Diatraea saccharalis (on sugarcane Saccharum spp.) and the fall armyworm Spodoptera frugiperda (on maize Zea mays); P. satan wasps significantly reduce crop pest damage. These results provide the much-needed baseline experimental evidence that social wasps have untapped potential as native biocontrol agents for sustainable crop production and food security. [ABSTRACT FROM AUTHOR]

Social insects depend on their nests for protection against predation and abiotic threats. Accordingly, the chemical compounds present in the material wasps use to build their nests can both facilitate communication and repel predators. It is herein hypothesized that different wasp species build their nests with different structure and substrate materials and that such materials consist of chemical compounds related to unique wasp behavior and outside temperature variation. To test this hypothesis, nests were collected from three species of social wasps, the samples of which were subjected to temperature variation under laboratory conditions. The compounds present in the substrate were analyzed by gas chromatography coupled to mass spectrometry. Chemical compounds identified in the nest material of the three species responded differently to temperature variation. Chemical compounds from Polybia nests were altered significantly when subjected to temperature variation, whereas the nests of Polistes versicolor did not significantly change in relation to the control. The differences found between Polistes and Polybia nests may be related to genetic factors, but also to the type of nest they construct. It is possible that divergent evolutionary strategies for maintaining colony temperature, as a function of the chemical composition of the nests, may have appeared between wasps that have open and closed nests. In relatively small colonies, nest substrate is more resistant to temperature variation because it is composed of a greater diversity of elements and thus capable of holding heavier, longer carbon chains. Our results suggest that chemical compounds in the nest material of the three wasp species analysed responded differently to fluctuating ambient temperatures and that such variation could result from the biochemical differences of unique wasp species or from thermoregulation strategies of colonies. • Compounds in the nest material maintaining thermostability against ambient elements. • Different answer of the compounds of the nest of species to temperature variation. • Wasp with open and closed combs have divergent strategie for keep colony temperature. • The composition of enveloped nest is more susceptible to temperature than open nest. • Polistes versicolor do possess a greater number of compounds. [ABSTRACT FROM AUTHOR]

Much work has shown that social isolation has lasting negative effects on adult social interactions, but less is known about precisely how and why isolation alters social behaviour. One way isolation may alter social behaviour is by interfering with the development of effective communication. Here, we test how social isolation influences individual recognition, a key aspect of social communication in Polistes fuscatus paper wasps. Polistes fuscatus reared in a typical social environment learn and remember the unique faces of conspecifics during social interactions. Typical P. fuscatus use individual face recognition to minimize conflict and stabilize social interactions. As wasps are adept face learners, they also readily learn to discriminate between wasp face images during training. Here, we show that social isolation had dramatic effects on recognition. We isolated wasps for 6 days after eclosion from pupation, then tested them for face recognition in social and nonsocial contexts. Isolated wasps did not learn and remember other individuals during social interactions. Furthermore, isolated wasps did not learn to discriminate between wasp face images during training. Therefore, social experience with conspecifics is essential for the development of individual recognition and face learning in paper wasps. Many aspects of wasp behaviour develop rapidly with little experience required. However, complex social interactions like individual recognition require social experience with conspecifics. • Wasps usually excel at using facial patterns to individually identify other wasps. • Social isolation during rearing interfered with individual recognition. • Isolated wasps did not learn unique faces during training or social interactions. • Social isolation interferes with wasp communication and social competence. [ABSTRACT FROM AUTHOR]

Paper wasps (genus Polistes) are one of the most species-rich genera of social insect. Prior studies have found that male coloration, male colour pattern, territory choice and female caste are potential drivers of intraspecific mate choice in paper wasps. However, there has been no formal assessment of interspecific mate choice in this group; therefore, the mechanism driving diversification in paper wasps remains an open question. In this study, we measured interspecific and intraspecific mating behaviour between two closely related species of paper wasps, Polistes fuscatus and Polistes metricus. These two species have ample opportunity to interbreed because P. fuscatus and P. metricus forage, nest and mate in the same habitats. We tested the strength of reproductive isolation between these species using no-choice and choice mating trials. Our results show strong, symmetric, prezygotic isolation between P. fuscatus and P. metricus. Males discriminated between conspecifics and heterospecifics but attempted to mate with females of the other species in ~10% of heterospecific mating trials. Female wasps were more discriminating than males and probably evaluated species identity and male quality through visual or olfactory cues. We additionally report sexual dimorphism in P. metricus body size. [ABSTRACT FROM AUTHOR]

Some animals are thought to exhibit cognitive specialization, as they have specialized cognitive modules that solve specific social or ecological problems instead of one general-purpose mechanism that addresses diverse problems. Although there are many examples of specialized cognition, little is known about whether specialization develops through experience or is produced by innate, species-specific differences. Previous work has shown that Polistes fuscatus wasps use face recognition to individually identify other wasps and that P. fuscatus are specialized for learning conspecific faces. Here, we test how experimentally altering face experience in three Polistes species influences the development of face specialization. We show face learning is influenced by both experience and innate, species-specific differences. In P. fuscatus , experience with conspecific faces is not required for the development of face specialization. In two related Polistes species that naturally lack individual face recognition, Polistes metricus and Polistes dominula , experience has different effects on specialization. Polistes metricus , a close relative of P. fuscatus , develops face specialization with experience. However, P. dominula , a more distant relative, uses general pattern recognition to learn faces regardless of experience. Therefore, some species have innate mechanistic architecture that facilitates the development of face specialization, while other species do not. These results suggest that selection shapes animal minds in a modular manner. The capacity for specialized cognitive skills evolves in response to specific ecological or social demands, such as social benefits associated with accurate individual face recognition. Highlights • We test whether cognitive specialization is inherited or requires experience. • We experimentally altered face experience in three species of paper wasps. • Experience produces face specialization in some wasp species but not others. • Face specialization in wasps is influenced by both inheritance and experience. [ABSTRACT FROM AUTHOR]

Mexican beetle Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) biological controlment on Parthenium hysterophorus L. plants in Gwalior (Madhya Pradesh). The four species of insects viz., the yellow paper wasp Polistes wattii Cameron (Hymenoptera: Vespidae); the two spotted stink bug Perillus bioculatus (F.) (Hemiptera: Pentatomidae); the predatory bug Eocanthecona furcellata (Wolff) (Hemiptera: Pentatomidae) and assassin bug Rhynocoris cf. fuscipes (Hemiptera: Reduviidae) were found as natural enemies of Z. bicolorata. It is the first report of predation of Mexican beetle by the yellow paper wasp and Rhynocoris bug. [ABSTRACT FROM AUTHOR]

In field experiments, an insect was trained to choose one of two visually different figures – A or B – in reference to situation (“situational learning”). Bees and wasps were shown to be able: 1) to choose A and to reject B at one location (place) of presentation of test figures and vice versa at the other location (at a distance of 1–8 m); 2) to choose A and to reject B at C-colored background and vice versa at D-colored background (at constant location). It is the first evidence of bees’ ability to make decisions depending on background color and the first evidence of wasps’ ability to perform situational learning. The described behaviors resemble “conditioned switching”, which is well known in vertebrates. Statistically significant individual differences between conspecifics have been recorded

Social wasps are common elements in Neotropics, although even elementary data about this taxon in Amazon region is partially unknown. Therefore the purpose of this work was to increase the knowledge of social wasp fauna at Jaú National Park. A total of 494 specimens of Polistinae was collected with active search, malaise trap and light trap. Forty-nine species belonging to fourteen genera were recorded. The richest genera were Polybia (14 species), Agelaia (07), Mischocyttarus (05), Apoica (04), Brachygastra (04) and Protopolybia (04); the remaining genera were represented by less than two species. The Jaccard similarity coefficient showed a higher similarity of the Jaú National Park with Ducke Reserve (Manaus, Amazonas). Four species were collected for the first time in Amazonas state Agelaia flavipennis (Ducke), Polybia affinis Du Buysson, Protopolybia nitida (Ducke) and Protopolybia sedula (de Saussure), only in Jaú National Park, showing the importance of this park for the social wasps preservation in the Amazon region. Fauna de Vespas Sociais (Hymenoptera: Vespidae: Polistinae) do Parque Nacional do Jaú, Amazonas, Brasil Resumo. Vespas sociais são elementos comuns na região neotropical, embora até mesmo a coleta de dados elementares sobre este táxon na região amazônica ainda é parcialmente desconhecido. Por isso objetivamos contribuir para o conhecimento sobre a fauna de vespas sociais que ocorrem no Parque Nacional do Jaú. Um total de 494 indivíduos de Polistinae foi coletado através de busca ativa, armadilha Malaise e armadilha luminosa. Quarenta e nove espécies de 14 gêneros foram registradas. Polybia (14 espécies), Agelaia (07), Mischocyttarus (05), Apoica (04), Brachygastra (04) e Protopolybia (04) são os gêneros com o maior número de espécies; os demais gêneros coletados foram representados por apenas duas ou uma espécie. De acordo com o coeficiente de similaridade de Jaccard, a composição de espécies de Parque Nacional do Jaú é semelhante a Reserva Ducke (Manaus, Amazonas). Agelaia flavipennis (Ducke), Polybia affinis Du Buysson, Protopolybia nitida (Ducke) e Protopolybia sedula (de Saussure) são considerados novos registros de ocorrência para o estado do Amazonas e foram coletados, até o momento, apenas no Parque Nacional do Jaú, demonstrando a importância deste parque para a preservação de vespas sociais na região amazônica.

Communication through vibrational signals is widespread among social insects and regulates crucial social activities. Females of the social wasp Polistes dominula produce substrate-borne vibrations on the combs by performing a conspicuous abdominal oscillatory behavior, known as abdominal wagging. Several studies have reported correlative evidence in support of its signaling role, but direct evidence is still lacking. Because abdominal wagging is strictly associated with the presence of larvae in the nest and with cell inspection, it has been suggested that it could be involved in adult--larvae communication. According to this hypothesis, abdominal wagging vibrations would have short-term effects related to food and trophallactic exchanges between adults and larvae by modulating salivary secretion (decreasing its amount, to prepare larvae to receive food, or stimulating the release of larval saliva to adults). Here, by using an electro-magnetic shaker, we assessed, for the first time, the short-term effects of abdominal wagging on larval behavior by recording larval responses and by measuring the amount of saliva released immediately after abdominal wagging playback. Our results show that larvae are able to perceive the substrate-borne vibrations produced by abdominal wagging and react by increasing the movement of their body, possibly in order to attract the attention of adult females during feeding nest inspection. Yet, we found that vibrations neither increase nor decrease the release of larval saliva. Our results support the hypothesis of the alleged role of vibrations in adult--larvae communications; however, they do not support the long- lasting hypothesis of salivary release modulation. [ABSTRACT FROM AUTHOR]

Vespula germanica (Fabricius) and Polistes dominula (Christ) are known to represent a significant threat to the biodiversity of ecosystems that they invade. Following their discovery in South Africa, there has been a lag in investigations into the presence and spread of both invasive wasp species in South Africa with limited action taken to address their expansion. Recent research indicated that populations of both species are still restricted to theWestern Cape Region, where the Cape Fold Mountain Belt seems to serve as a barrier to further spread to the rest of South Africa. The limited distribution range creates a favourable scenario for management efforts and, if acted on rapidly, increases the possibility of successful control. Various control methods, including mechanical, chemical and biological control have been developed and implemented internationally in an effort to curb population expansion of social wasps. These methods, together with a summary of the initiatives that have been launched locally to control these wasp species, are discussed in this review. [ABSTRACT FROM AUTHOR]

Social wasps encompass species displaying diverse social organization regarding colony cycle, nest foundation, caste differences (from none to significant dimorphism) and number of reproductive queens. Current phylogenetic data suggests that sociality occured independently in the subfamily Stenogastrinae and in the Polistinae+Vespinae clade. In most species, including those with the simplest social organization, colony reproduction is monopolised by a single or few females. Since their nest mates can also develop ovaries and lay eggs, dominant females must somehow inhibit them from reproducing. Physical interactions in the form of open aggression or, usually, ritualised dominance by the fertile females contribute to fertility inhibition in several species, but it is unlikely to function in large colonies. In the latter case, reproduction within the colony is likely to be regulated through pheromones. Relatively little is known about these semiochemicals. Studies on all the three social wasp subfamilies, revealed that cuticular hydrocarbon components differ in abundance between egg-laying and not egg-laying females and that their composition depends on fertility status. In several species, females have been reported to manifestly react towards females with activated ovaries, but there is little evidence to support the hypothesis that fertile individuals are either recognized through their CHC composition, or that over-represented CHC constituents can inhibit fertility. Moreover, very little information exists on the possibility that exocrine glands release fertility signals or chemicals inhibiting fertility. [ABSTRACT FROM AUTHOR]

It has been recently suggested that female mate choice, based on sexually selected ornaments, is an important component of social wasps’ reproductive biology. The correlates of male ornaments that could be of a female’s interest, however, remain to be investigated. Males of the Neotropical paper wasp Polistes simillimus have sexually dimorphic melanin-based black spots on their faces. In this species, male spots work like sexual ornaments, as it has been experimentally demonstrated that females prefer sexual partners with a higher proportion of black pigment on their faces. We have shown that, under laboratory conditions, male sexual ornamentation positively predicts the strength of the melanization immune response and longevity. Therefore, in P. simillimus , melanin-based facial patterns (ornaments) seem to be honest indicators of male quality. [ABSTRACT FROM AUTHOR]

We investigated associative learning of food odors by the European paper wasp Polistes dominula Christ (Hymenoptera: Vespidae) because of consistent low rates of attraction to food materials in laboratory assays. We hypothesized that wasps in nature exhibit nonspecific food-finding behavior until locating a suitable food, and then respond more strongly and specifically to odors associated with that food reward. Female P. dominula workers exhibited higher rates of attraction in a flight tunnel to piped odors of fermented fruit purees following previous experience with that puree, compared to wasps with no prior experience with the fermented fruits. Attraction behavior included upwind-oriented flight and casting within the odor plume, indicative of chemoanemotaxis. Synthetic chemicals representative of volatiles P. dominula may encounter in nature while foraging was also tested. Similar increases in attraction responses occurred following feeding experience with a sugar solution that included either 3-methyl-1-butanol or pear ester, but not eugenol. These experimental results support the hypothesis of associative learning of food odors in P. dominula. We discuss the ecological relevance of our results and suggest an alternative approach to trap paper wasps in pest situations utilizing learned chemical attractants. [ABSTRACT FROM AUTHOR]

When males and females have distinct behaviour, learning may vary between the sexes. Polistes fuscatus wasps provide an interesting model to study sex differences in learning because males and females have different social behaviour. Female wasps have highly variable facial patterns used for individual face recognition, live in cooperative groups where interactions depend on individual face recognition and excel at learning female faces. In contrast, male wasps lack the type of variable facial patterns necessary for individual face recognition and do not participate in the type of social interactions known to favour individual recognition in females. Instead, males leave the nest soon after adulthood and devote their energy to mating. Given the behavioural differences between males and females, females may be more adept at learning wasp faces than males. Here, we train male and female P. fuscatus to discriminate between pairs of female P. fuscatus face images and pairs of colours. Females learned to discriminate between pairs of face images more accurately than males. However, males and females were equally adept at colour learning, indicating that there are no generalized sex differences in learning. The sex differences in face, but not colour, learning are consistent with the adaptive specialization hypothesis, which posits that cognitive abilities are selected to solve particular social or ecological problems. Overall, general learning capacity is similar across male and female wasps, but face learning is shaped by sex-specific recognition behaviour. [ABSTRACT FROM AUTHOR]

Research on individual recognition often focuses on speciestypical 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. Individual recognition mediates dominance interactions among foundresses. Three previously published experiments have shown that foundresses (1) benefit by advertising their identity with distinctive facial patterns that facilitate recognition, (2) have robust memories of individuals, and (3) rapidly learn to distinguish between face images. Like foundresses, workers have variable facial patterns and are capable of individual recognition. However, worker dominance interactions are muted. Therefore, individual recognition may be less important for workers than for foundresses. We find that (1) workers with unique faces receive amounts of aggression similar to those of workers with common faces, indicating that wasps do not benefit from advertising their individual identity with a unique appearance; (2) workers lack robust memories for individuals, as they cannot remember unique conspecifics after a 6-day separation; and (3) workers learn to distinguish between facial images more slowly than foundresses during training. The recognition differences between foundresses and workers are notable because Polistes lack discrete castes; foundresses and workers are morphologically similar, and workers can take over as queens. Overall, social benefits and receiver capacity for individual recognition are surprisingly plastic. [ABSTRACT FROM AUTHOR]

RNA interference (RNAi) is a useful tool to assess gene function by knocking down expression of a target gene and has been used successfully in domestic and laboratory organisms. However, the use of RNAi for functional genomics has not fully extended into ecological model organisms in natural environments. Assessment of gene function in the wild is important because gene function can be environmentally and context dependent. Here, we present a case study using RNAi to assess gene function in wild paper wasps Polistes metricus, to test roles for two candidate genes ( NADH dehydrogenase ( NADHdh) and retinoid and fatty acid binding protein ( RfaBp)) in the development of reproductive castes. Previous studies have shown that these genes are upregulated in larvae that become queens compared to workers, but this pattern was reversed in the laboratory, making field-based studies necessary. We orally administered dsRNA to larvae in field colonies and found evidence of a short-term knockdown followed by a compensatory rebound in expression for RfaBp. We also observed the predicted worker-like decrease in lipid stores in NADHdh dsRNA treated wasps, suggesting a possible role for NADHdh in caste development. We discuss our results in the context of challenges for using RNAi for functional genomics in ecological model organisms in the field. [ABSTRACT FROM AUTHOR]

Purpose: To compare the outcomes of ocular injuries of hornets and paper wasps’ stings.Study design: Retrospective case series.Methods: Patients diagnosed with ocular injuries sustained by bee stings at Miyata Eye Hospital (Miyazaki, Japan) between August 2000 and July 2016 were enrolled. Retrospective data regarding type of bee, visual acuity, and treatment were collected from medical records. Outcomes of the hornet and wasp groups were compared.Results: Five eyes of 5 patients (3 men, 2 women; mean age 44.6±21.2 years [range 9-62 years]) were enrolled. The mean follow-up period was 50.6 ± 57.6 months (range 4 days to 121 months). The causative bee was hornet in 3 cases and wasp in 2. The anterior chamber was irrigated in 2 patients, both from the hornet group. The best-corrected visual acuity at the final visit was no light perception, light perception, and (0.02) in the hornet group, (1.5) and (1.2) in the wasp group.Conclusions: The hornet group exhibited significantly worse prognosis than the wasp group. Identifying the type of bee is important in establishing prognosis. [ABSTRACT FROM AUTHOR]

Body size limits brain volume, but size may also differentially constrain the volumes of brain regions. Size variation and compartmentalized brains of swarm-founding paper wasps (Epiponini) make them good models for the study of size-related brain allometry. We analysed the relative volumes of brain regions that process different sensory inputs: the optic lobes (OL, vision), the antennal lobes (AL, chemosensation) and insect forebrain neuropils (MB, mushroom bodies). Species varied 25-fold in head capsule volume. Total brain volume increased with body size. This brain size increase was a non-linear decelerating function of size: relative brain volume was highest for the smallest-bodied species. In contrast, relative MB and AL volumes declined sharply at the smallest wasp body sizes, but relative OL size did not. Different brain regions showed distinct size-related allometries among Epiponinae. Such brain allometry differences should be accounted for in comparative analyses of brain evolution. However, there was significant deviation from size-typical brain architecture in the nocturnal genus Apoica: A. pallens had reduced relative investment in OL but greater relative investment in MB visual processing regions (calyx collars). This suggests that body size effects on brain region investment can be overcome by selection on particular sensory systems when species evolve to occupy novel sensory environments. [ABSTRACT FROM AUTHOR]

Intraspecific variation in sperm morphometric is widespread across animal taxa and it might be related to different aspects of sexual selection. Within social insects, it has only been documented for some bee and ant species. Here we provided a detailed description of the variation in sperm morphometric in the paper wasp Polistes simillimus Zikan (Hymenoptera Vespidae). Light microscopy, digital photography and digital analyses were used to measure sperm (total length, head and flagellum length). Considering a single population from which we sampled four colonies, seven males of each colony and 30 sperm cells of each male (total 840 cells), the overall dimensions of P. simillimus spermatozoon is: total length 107 ± 7 (80-129) µm, coefficient of variation, CV = 8%; flagellum length 91 ± 7 (62-114) µm, CV = 7%; head length 16 ± 2 (9-30) μm, CV = 9%. We found that variation in the sperm constituent parts (head and flagellum) contribute to explaining the variation in total sperm length. However, the size of these parts varies independently. Besides, sperm total length and flagellum length differed between males, but not between nestmates and between colonies, while variation in sperm head was similar across all these levels of analyses. Finally, sperm morphometric is not associated with male body size. We discussed implications of our results for the study of sperm morphometric in insects, sampling procedures for estimating species-typical sperm size in social insects and the possibility of variation in male sperm quality in social wasps. [ABSTRACT FROM AUTHOR]

The Roraima state in Brazil is part of Northern Amazon, an area harboring high biodiversity and high degree of endemism. Nevertheless, there are few studies on diversity of social wasps occurring in this region. This study presents a list of social wasps (Vespidae: Polistinae) collected actively and using Malaise, Suspended and Light trap in six localities in Roraima state. A total of 85 species of 14 genera were collected. Fourty-five of these species are new distribution records to Roraima state, some species are not common found in the collections and lists of species, and some are recorded for the second time to Brazil or the Amazon region. This increase may be an indication that the Polistinae richness is probably higher in the regions studied and that Roraima may well contain a number of additional (as yet unrecorded) social wasp species. More comprehensive studies are needed in order to increase the knowledge of wasp species in Roraima, contributing to increased knowledge of the diversity in Northern Brazil.

Social wasps are common elements in Neotropics, although even elementary data about this taxon in the Amazon region is partially unknown. Therefore the purpose of this work was to increase the knowledge of social wasp fauna at the Ducke Reserve. One hundred and three species belonging to nineteen genera were recorded. The richest genera were Polybia (28 species), Agelaia (12) and Mischocyttarus (12). Seventy species was collected in active search, 42 species using Malaise trap, 25 suspended trap, 20 attractive trap and nine light trap. Ducke Reserve has one of the highest number of Polistinae wasps in reserves or parks in the Neotropic region.

Understanding the developmental and evolutionary processes that generate and maintain variation in natural populations remains a major challenge for modern biology. Populations of Polistes fuscatus 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. Distinctive identity-signalling phenotypes facilitate recognition, which reduces aggression between familiar individuals in P. fuscatus wasps. Selection for identity signals may increase phenotypic diversity via two distinct modes of selection that have different effects on genetic diversity. Directional selection for increased plasticity would greatly increase phenotypic diversity but decrease genetic diversity at associated loci. Alternatively, heritable identity signals under balancing selection would maintain genetic diversity at associated loci. Here, we assess whether there is heritable variation underlying colour pattern diversity used for facial recognition in a wild population of P. fuscatus wasps. We find that colour patterns are heritable and not Mendelian, suggesting that multiple loci are involved. Additionally, patterns of genetic correlations among traits indicated that many of the loci underlying colour pattern variation are unlinked and independently segregating. Our results support a model where the benefits of being recognizable maintain genetic variation at multiple unlinked loci that code for phenotypic diversity used for recognition.

The aim of the present work was to discover how many species inhabit the environs of Brasília. Being an approximate rectangle in the middle of the Cerrado biome, the Federal District of Brasília is a representative “quadrat” to sample the biome’s fauna.

The aim of this study was to explore whether the nest chemical profile (NCP) can be used to determine intra- and interspecific differences in social wasps of the subfamily Polistinae. For this purpose, Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was used to directly analyze small pieces of nest as well as the gasters of females. An advantage of the methodology was that no sample preparation was required. FTIR-PAS combined with multivariate discriminant analyzes was used, to the best of our knowledge for the first time, to evaluate the NCPs of six species of polistine wasps, observing the influence of the nesting environment and investigating the relationships among the nest and female cuticular chemical profiles. The results revealed significant inter-species differences among the NCPs, as well as strong correlations with the environments in which the nests were located. The Mischocyttarus and Polistes species belong to the same tribe (Polistini) and therefore exhibited similar NCPs. These species were separated from the Polybia species in the NCP dendrogram, mainly because the Polybia belong to another tribe (Epiponini). Correlation was observed between the NCPs and the cuticular chemical profiles of females. The findings of the study demonstrated the importance of the NCP for differentiation of species and environments, and the utility of FTIR-PAS for identification of correlations between individuals and nests. The results confirmed the hypothesis that the NCP can be used as an additional tool for intra- and interspecific differentiation in social wasps of the subfamily Polistinae. [ABSTRACT FROM AUTHOR]

Nestmate discrimination in the paper wasp, Polistes metricus Say (Hymenoptera: Vespidae) was examined during each stage (nesting and non-nesting phases) of the colony cycle. Resident wasps of each caste were paired with nestmates or non-nestmates of the same caste in a clear plastic box near the nest in the field and all aggressive and non-aggressive behavioral interactions initiated by the resident wasps were noted. Each wasp caste, particularly the resident foundress, workers, and males exhibited a significantly high proportion of aggressive behaviors towards non-nestmates than towards nestmates, thus demonstrating nestmate discrimination. However, the response of resident fall gynes towards nestmates and non-nestmates was not significantly different. During winter, gynes of P. metricus and P. fuscatus Fabricius were found to overwinter together in the same clusters. The overwintering gynes of P. metricus showed complete tolerance towards conspecifics (non-nestmates) and allospecifics (P. fuscatus). These findings suggest that the acceptance threshold of P. metricus shifts from being restrictive towards the beginning of the nesting phase to being permissive towards the end, which differs from previous studies on P. fuscatus, whose acceptance threshold was more restrictive during the reproductive phase than during the worker phase. However, during the non-nesting (overwintering) phase of the colony cycle, the acceptance threshold likely becomes even more permissive to an “accept-all” level in both species. These shifts in acceptance threshold follow the predictions of Reeve's (1989) conspecific acceptance threshold model, and most likely reflect the cost-benefit ratio assessment of wasps to minimize negative inclusive fitness consequences at each stage of the colony cycle. [ABSTRACT FROM AUTHOR]

Eusocial insect reproductive castes (in Hymenoptera, female reproductive queens and sterile workers) differ dramatically in behavior. Castes may differ in the cognitive demands that affect patterns of brain tissue investment. Queens and workers diverge most strongly in the advanced eusocial, or swarm-founding species, where queens do not forage and rarely leave their nests. We asked whether reproductive castes of swarm-founding paper wasps in the tribe Epiponini differed in the relative sizes of their mushroom bodies (MB), a key brain region involved in sensory integration, and in learning and memory. We measured brain-size corrected volumes of the MB dendritic-field neuropils (calyces) and the MB axonal bundles (peducles and lobes) for queens and workers from 16 species of 10 genera of the tribe Epiponini. The subject species spanned much of the epiponine phylogeny, differing in colony size and degree of caste differentiation. Queens had significantly higher relative MB investment than workers, both for the MB in toto and for the MB calyces. The magnitude of queen-worker MB size differences did not covary significantly with body size, but species with larger colonies had stronger caste differences in MB size. A review of caste differences in MB volume across a wide range of social Hymenoptera taxa suggested a positive association of MB investment with social dominance is widespread. Significance statement: Social insect castes (reproducing queens and sterile workers) differ strongly in behavior, particularly in swarm-founding species where queens are largely nest-bound. Caste comparisons are a powerful model for understanding brain/behavior relationships. We measured the relative size of a key insect brain region, the mushroom bodies (MB), in 16 swarm-founding wasp species. MB are involved in sensory integration, and in learning and memory. Queens had relatively larger MB than workers, and the magnitude of the queen-worker differences increased with species average colony size. We suggest the reproductive dominance and social contact of nest-bound queens promotes greater mushroom body investment. [ABSTRACT FROM AUTHOR]

When helpers from cooperative breeding animals have some expectation of direct reproduction, there is potential for conflict over how much aid they should provide to the colony. For example, if food is shared among all colony members, then higher levels of foraging by a helper would be desirable for the colony as a whole. However, because foraging is risky and physiologically costly, hopeful reproductive helpers could avoid foraging. Evidence suggests that this work-conflict could be resolved if helpers are aggressively coerced by their nestmates to provide aid. Here, we showed that in the primitively eusocial paper wasp Polistes versicolor, colony food starvation leads to an increasing in aggression that results in an increasing activity level (including foraging). We propose that aggression affects forage levels because (i) attacks from nestmates are directed toward known foragers rather than non-foragers; and (ii) resting wasps generally respond to aggression by becoming more active while already active wasps generally respond by switching the task they were doing. In P. versicolor, direct reproduction is an option for helpers. It means that they can be considered as hopeful reproductive individuals seeking to avoid performing risky behaviours, like foraging. In this sense, decentralized aggression from nestmates could be a coercive mechanism to force wasps performing undesirable tasks, while simultaneously enhancing the performance of a variety of other tasks. [ABSTRACT FROM AUTHOR]

The prevailing paradigm for social wasp endocrinology is that of juvenile hormone (JH) functioning pleiotropically in potential and actual queens, where it fuels dominance behaviors, stimulates ovarian growth and/or affects the production of status-linked cuticular compounds. In colonies with annual cycles (e.g., temperate-zone species), female adults produced at the end of the summer (called gynes) are physiologically primed to hibernate. Despite the absence of egg-laying in the pre-overwintering phase, gynes engage in dominance interactions that may affect reproductive potential following hibernation. JH levels have long been inferred to be low in gynes but this has never been tested. In what is the first study to measure JH in gyne-containing colonies of a temperate paper wasp, and the first to incorporate hormone assays in Belonogaster , our results show that the JH titer positively correlates with gyne-specific traits (including oocyte length and a low frequency of foraging trips) in B. longitarsus , a South African paper wasp. Measures of dominance correlated with oocyte length, but not all dominant females possessed activated ovaries. The cuticular hydrocarbon profiles of gynes and workers were distinct, with oocyte length and JH titer showing a positive association with longer-chain methyl-branched alkanes. Nonetheless, evidence for a role of JH in dominance was inconclusive. Finally, the range of JH titers among gynes, and the positive association of JH titers with ovarian status and prospective fertility signals, makes it unlikely that the gyne phenotype is maintained by low JH levels. [ABSTRACT FROM AUTHOR]

Polistes paper wasps have striking and variable colour patterns. Although these colour patterns are known to function in communication, little is known about how they affect fitness in relation to the abiotic environment. In the present study, we used dried-preserved museum specimens, comprising male and female Polistes from all over the world, aiming to test for a correlation between the body luminance (assessed by digital photography) and environmental temperature (assessed by the available online environmental databases). We found that the female thorax and abdomen are darker (low luminance) in colder compared to warmer environments. In males, however, body luminance is not associated with environmental temperature. Theoretical and empirical evidence suggests that darker insects have an advantage in colder environments because they can heat faster than lighter ones (thermal melanism hypothesis). By showing that melanic Polistes inhabit cooler areas more than the brighter species, we presume that selection for effective heating may provide an adaptive explanation for the evolution of Polistes colour diversity. [ABSTRACT FROM AUTHOR]

The two paper wasps, Polistes dominula and Polistes gallicus, are related species with strongly differing distribution ranges. We investigated thermal tolerance traits (critical thermal limits and metabolic response to temperature) to gain knowledge about physiological adaptations to their local climate conditions and to get evidence for the reasons of P. dominula's successful dispersion. Body and ambient temperature measurements at the nests revealed behavioural adaptations to microclimate. The species differed clearly in critical thermal minimum ( P. dominula −1.4 °C, P. gallicus −0.4 °C), but not significantly in critical thermal maximum of activity ( P. dominula 47.1 °C, P. gallicus 47.6 °C). The metabolic response did not reveal clear adaptations to climate conditions. At low and high temperatures, the metabolic rate of P. dominula was higher, and at intermediate temperatures, we determined higher values in P. gallicus. However, the species exhibited remarkably differing thermoregulatory behaviour at the nest. On average, P. gallicus tolerated a thoracic temperature up to ~41 °C, whereas P. dominula already tried at ~37 °C to keep the thorax below ambient temperature. We suggest this to be an adaptation to the higher mean ambient temperature we measured at the nest during a breeding season. Although we determined for P. dominula a 0.5 °C larger thermal tolerance range, we do not presume this parameter to be solely responsible for the successful distribution of P. dominula. Additional factors, such as the thermal tolerance of the queens could limit the overwintering success of P. gallicus in a harsher climate. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]