Hole repair and the influence of learning on nest repair in the paper wasp,Polistes fuscatus (Hymenoptera: Vespidae)

Two methods of hole repair used by the paper wasp, Polistes fuscatus,were examined and compared, and the hypothesis that nest repair behavior may improve with experience was tested. Similarly sized holes were repeatedly made in the sides of nests and the repair behavior of the nest residents was recorded. The distance of the hole from the cell mouth determined which repair method was used. In addition, both the amount of time for hole repair completion and the number of pulp loads used in making the repair decreased significantly with experience.     

Ground nesting in the paper wasp <Emphasis Type="Italic">Polistes aurifer</Emphasis> (Hymenoptera,Vespidae)

Summary Polistes paper wasp species vary in their nest site selection, with some nesting in relatively exposed areas and others in protected cavities. Locating the nest sites of cavity dwelling species in natural habitat can prove difficult, and most behavioral studies on these species are therefore conducted using human-built structures. Since Hungerford and Williams (1912) and Rau (1929) noted the location of several P. fuscatus (Fabricius) nests in rodent burrows, there have been no published accounts of ground nesting Polistes species. I report the occurrence of a large, dense cluster of P. aurifer (Saussure) nests located within cracks in the dried soil of the Santa Monica Mountains of southern California, USA.Received 8 April 2003; revised 10 October 2003; accepted 31 October 2003.     

Ultrastructural features of the hypopharyngeal glands in the social wasp Polistes versicolor (Hymenoptera: Vespidae)

The wasps of the genus Polistes have been considered the key to understanding the evolution of social behavior in Hymenoptera. Several studies have shown that the development of organized insect societies was accompanied by the evolution of structures like exocrine glands, which became specialized to perform specific functions. This article investigates the ultrastructural and cytochemical features of the hypopharyngeal glands of Polistes versicolor. These glands have been studied in depth in social bees, where they occur only in nurses and produce the royal jelly. Our results revealed that these glands basically did not vary among individuals or between sexes. They are constituted by spherical cells, each with a large nucleus and well‐developed rough endoplasmic reticulum. Secretion vesicles are abundant, but lipid droplets were not observed, indicating that these glands may not have a role in pheromone synthesis. Acid phosphatase was detected in lysosomes, and also free in the cytosol, but did not seem to be related with cell death. Thus, our results suggest that the hypopharyngeal glands of P. versicolor may not have a specialized social role, but could produce digestive enzymes.     

Usurpations and late associations in the solitary founding social wasp,Polistes biglumis bimaculatus (Hymenoptera: Vespidae)

One hundred twenty-five colonies of a population of the montane, haplometrotic, paper waspPolistes biglumis bimaculatus were marked for identification and then periodically surveyed during an entire summer period. This made it possible to record intraspecific nest usurpations (both single and multiple) and to observe associations between two females, defined here as late associations. Both usurpation and late association occurred primarily in the latter half of the preemergence period. Some evidence suggests that a foundress usurps a conspecific nest as a consequence of her own nest failure. After nest failure, usurpation and late association are the only available options for achieving reproductive success because, in the mountain habitat, the short summer does not allow for successful renesting. Late associations generally occurred earlier than usurpation. However, our evidence suggests that nest usurpation and late association may be the same phenomenon.     

Nest surface hydrocarbons facilitate nestmate recognition for the social wasp,Polistes metricus Say (Hymenoptera: Vespidae)

Nestmate recognition was observed inPolistes metricus Say workers only if the workers were exposed to their nest surface hydrocarbons after eclosion. If the newly emerged workers were never exposed to the nest hydrocarbons as adults, they showed no discrimination between nestmates and nonnestmates. Furthermore, the newly emerged workers were accepted more readily by their experienced nestmates than by experienced nonnestmates only if the newly emerged wasps had been exposed to the nest surface hydrocarbons. This reciprocal recognition implies that the nest recognition cues are nest surface hydrocarbons that are learned and that may be acquired byP. metricus workers as adults on the natal nest.     

Can venom volatiles be a taxonomic tool for Polistes wasps (Hymenoptera,Vespidae)?

In the present study, we investigated whether venom volatiles have a species-specific composition and could possibly be used to discriminate between related paper wasp species. We compared venom volatile chemical profiles, obtained through gas chromatography-mass spectrometry analyses, of three non-parasitic European Polistes species ( P. dominulus , P. gallicus and P. nimphus ). The results show that the venom volatile composition is indeed species specific and can thus be a useful systematic tool.     

A role of the Dufour's gland in the dominance interactions of the paper wasp,Polistes fuscatus (Hymenoptera: Vespidae)

The Dufour's gland of the paper wasp, Polistes fuscatus,is a source of the cues used by dominant females to recognize the eggs laid by subordinates or nonnestmates on pre (worker)-emergence nests. When dominant wasps were presented with an egg covered with either (1) the Dufour's gland extract of a subordinate cofoundress, (2) the extract of an egg from the same subordinate, or (3) the solvent alone, the dominant female destroyed and replaced the eggs covered with the Dufour's extract significantly more frequently than the other eggs. Eggs with the extract of a nonnestmate's Dufour's gland were also eaten significantly more frequently than those with the solvent. Given similar choices, subordinates did not destroy any eggs. The Dufour's gland appears to have little or no role in communicating dominance directly among aggressively interacting cofoundresses.     

Age polyethism and defense in a tropical social wasp (Hymenoptera: Vespidae)

Although tapping the nest in simulated vertebrate attack caused all but 1-day-old workers of Polybia occidentalis to rush from inside and cover the envelope, defense itself—attack of a target—was shown to be carried out only by workers older than about 10 days. While foraging was also performed by older workers, the frequency-age distribution of defensive behavior was skewed to a significantly younger age than was that of foraging. The plot of mean individual probability of defending as a function of age was logistic, leveling off at 0.11 by the age of about 13 days. The distribution of the probability of defending among workers 13 days of age was random, indicating that there is no specialized defender class among older workers. Workers that defended were recruited from among both nest workers and foragers. Although foragers were more likely to defend than were nonforagers, nonforagers contributed more individuals to the pool of defenders because they were more numerous.     

Amino acid composition of the protein in preemergence nests of Polistes (Polistes) riparius, and its similarity to the consubgeneric wasp, P. (P.) chinensis (Hymenoptera: Vespidae)

Amino acid composition of the protein in the oral secretion, which is widely used for construction and maintenance of social wasp nests, was analyzed in preemergence nests of Polistes (Polistes) riparius. The kinds and proportion (%) of amino acids of the protein detected from nests of P. riparius were very similar to those of a consubgeneric species, P. (P.) chinensis, but were conspicuously different from those of other social wasp genera. Further, it was estimated that protein contents in oral secretion of P. riparius were nearly the same as those of P. chinensis; namely, foundresses of P. riparius, which build much larger nests than those of P. chinensis, did not reduce relative protein contents to produce more oral secretion at a smaller cost. Amino acid composition may reflect phylogenetic relationships among wasp taxa. Received: March 10, 2000 / Accepted: May 29, 2000     

Observations onApoica pallens,a nocturnal neotropical social wasp (Hymenoptera: Vespidae,Polistinae, Epiponini)

Summary Colonies and nests ofApoica pallens in the llanos region of Venezuela range from small foundress nests to large mature colonies. Nests are sited on small diameter, near-horizontal branches in a variety of shrub and tree species. During the day, adult wasps cluster on the face of the nest in an array that seems to be determined by orientation to gravity; defense of the colony against parasitoids and ants by the resting wasps may be more a passive than an active behavior. Wasps fan their wings to cool the colony during the day, but no foraging for water accompanies the fanning behavior. Nightly foraging activity begins with the explosive departure from the nest of hundreds of wasps, most of which rapidly return. Moderate foraging levels early at night give way to very low foraging levels in pre-dawn hours. The period of moderate foraging may be extended for longer hours during increased moonlight. Foraging wasps collect arthropod provisions for larvae. Larvae produce a trophallactic saliva; adults engage in inter-adult trophallaxis; brood are cannibalized. During cluster formation prior to swarm emigration, adult wasps do not appear to scent-mark substrates such as leaves. Instead,A. pallens exhibits a calling behavior, unique among polistine wasps studied to date, in which the gaster is held rigidly away from the thorax and metasomal sternal glands are exposed. Swarms can emigrate during the day.A. pallens may incorporate absconding and colony relocation as features of its colony cycle in the highly seasonal llanos.     

Venom as an interspecific sex pheromone, and species recognition by a cuticular pheromone in Paper Wasps (Polistes, Hymenoptera: Vespidae)

ABSTRACT. The venoms of Polistes fuscatus (subspecies fuscatus) (F.) and P. exclamans Viereck from sympatric populations in North Carolina, U.S.A., contain a pheromone which attracts males and stimulates sexual behaviour in both conspecific and heterospecific males. Males of P. fuscatus (subspecies variatus Cresson), a subspecies from Wisconsin, respond to venom of P. fuscatus fuscatus, P. exclamans, and Vespula maculifrons (Buysson) from North Carolina, although the levels of response to P. exclamans and V. maculifrons venom are less than that to P. fuscatus variatus venom.
Caged Wisconsin P. fuscafus males do not attempt to mate with P. exclamans females, but will attempt to mate with conspecifics. A series of bioassays indicates that males discriminate between females of P. fuscatus and P. exclamans on the basis of chemical, rather than behavioural or visual cues. The venom apparently is not important in species recognition. Instead, the results of two sets of bioassays suggest that species recognition is mediated by a surface pheromone on the cuticle of females.     

Nest recognition in neighboring colonies: a comparison of two European species of Polistes wasps (P. dominulus and P. nimphus, Hymenoptera: Vespidae)

The ability of two species of Polistes wasps to distinguish their own from nearby nests was tested, following the procedure used by Espelie et al. Our experiments demonstrated that, in the laboratory, females of Polistes dominulus and Polistes nimphus preferentially selected their own nests rather than nearby nests. We also evaluated the role of odor cues in nest recognition by washing nests in hexane to remove the apolar solvent-soluble components of nest odor. Although P. nimphus females continued to discriminate nests even after washing, P. dominulus individuals failed to discriminate between their own and a foreign neighboring nest. In both species, wasps were able to recognize their own nests when nest extracts were subsequently reapplied to the nest surface. These results indicate that P. dominulus wasps recognize their nests through perception of nest odor. The ability of P. nimphus wasps to distinguish their own nests even after presumed removal of the nest odor is discussed. Received: January 27, 2000 / Accepted: May 22, 2000     

Isolation and characterization of 10 microsatellite loci in the paper wasp Polistes rothneyi (Hymenoptera; Vespidae)

We developed 10 polymorphic microsatellite loci for the Japanese paper wasp Polistes rothneyi using the magnetic particle method. Eight of the 10 loci tested were highly polymorphic, having four to eight alleles in P. rothneyi with an expected heterozygosity of 0.60–0.75. They also appeared to be applicable to other related species such as Polistes jokahamae. These loci can be used to study parameters concerning genetic relatedness such as worker reproduction and kin structure.     

Information analysis by the paper wasp,Polistes fuscatus,during nest construction (Hymenoptera,Vespidae)

Summary The building decision process of the paper wasp,Polistes fuscatus, was studied by 1) analyzing the search pattern of the wasps prior to the addition of pulp to different areas of the nest, 2) comparing the pulp addition needs of the cell chosen for lengthening to those of other cells in the nest, and 3) presenting the wasps with eight types of dichotomous building choices, which provided information about the relative influence of different building cues. Wasps conduct a hierarchical search prior to pulp addition, which means that they search the comb face and petiole disproportionately more often and more thoroughly than the comb back and sides. Once a particular nest area triggers closer scrutiny, comparisons are made with adjoining areas. The most needy location is then chosen based on nest cues. When lengthening a cell, the development of the brood and relative cell length have a strong influence on which cell is chosen at all times, while distance of the brood from the cell mouth becomes important during the later stages of brood development. The results indicate that there is no simple hierarchical weighting of cues. The decision process involves comparisons among multiple cues, which for the most part have an additive influence when variation in relative cue strength is considered.     

Larval sex identification in the paper wasp <Emphasis Type="Italic">Polistes dominulus</Emphasis> (Vespidae,Hymenoptera)

Identifying the sex of larvae is important in social Hymenoptera. Until now for Polistes wasps it has been necessary to genotype larvae at microsatellite loci, and assign their sex based on homozygosity at these loci. In our study on the paper wasp Polistes dominulus we have found morphological differences between larval sexes that can be used for larvae from the 3^rd instar on to easily and cheaply identify larval sex: the external gonopore and the shape and size of larval gonads. The robustness of these indicators was supported by genotype data at four microsatellite loci. Using gonopore and gonad features for sex assignment will assign diploid males as males, unlike techniques based on genetic loci or chromosomes. Received 12 July 2006; revised 4 January 2007; accepted 5 February 2007.     

Venom spraying inParachartergus colobopterus: A novel defensive behavior in a social wasp (Hymenoptera: Vespidae)

Colonies ofParachartergus colobopterus do not defend against vertebrates by attacking and stinging. Instead, defending workers bend the gaster forward and spray a fine mist of venom in the direction of nearby moving objects. Although venom spraying has been reported forP. fraternus, a species that does sting, we found that this occurred only during sting attempts. We conclude that defensive behavior inP. colobopterus is unique among wasps in that (1) venom is sprayed at intruders by workers standing on the nest and (2) the spray is an atomized mist rather than a stream. We suggest that nest crypticity restricts vertebrate predators on this wasp to small, insect gleaning birds, against which a spray of venom in the eyes, mouth, and nasal passages is more effective than is a stinging defense.     

Early male production is not linked to a reproductive strategy in the Japanese paper wasp,<Emphasis Type="Italic"> Polistes chinensis antennalis</Emphasis> (Hymenoptera: Vespidae)

Diploid males in haplo-diploid insects are sterile, because they produce diploid sperm. Our previous report revealed that early males of the Japanese paper wasp Polistes chinensis antennalis are diploid but did not reveal how often this occurs. We analyzed the genotypes of early males using six microsatellite markers. Two of the 41 early males (5%) from six colonies were haploid, but the other males were diploid. This evidence suggests that we can ignore the reproductive success of the early males of P. chinensis antennalis.