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In Polistes paper wasps, haploid early males can mate with early emerging females and leave viable offspring. In contrast, diploid early males are eventually sterile because they contribute triploid offspring via diploid sperm. Clarifying the ploidy of early males is important for determining whether early male production is a reproductive strategy for the species. We examined the mating behavior and the ploidy of early males in the Japanese paper wasp, Polistes rothneyi iwatai van der Vecht. Thirteen early males from four colonies were all diploid. Two of the nine early males (22.2%) attempted to mate with females, but only one individual (11.1%) was successful (the female's spermatheca contained spermatozoa). These results suggest that although most early males of P. rothneyi iwatai do not produce offspring, their mating may be linked to the occasional production of triploid females. [ABSTRACT FROM AUTHOR]

This study presents the first observations of early-season colony development of Ropalidia plebeiana in Canberra, Australia. The growth pattern of three R. plebeiana nests was measured during weekly observations from October 2006 to January 2007 and showed that nests steadily increase in size over the early summer to approximately 50 cells when the nest is newly established and to approximately 170 cells when nests from the previous season are re-used. A first generation of adult females is produced by December, and the bimodality of the curves of egg, larval and pupal numbers indicates that these three developmental stages last approximately 2–3 weeks each. The nesting cycle of R. plebeiana in Canberra commences approximately 2 weeks later than in coastal Australia, the shorter summers in this inland region restricting the length of the active season. R. plebeiana did not form dense nesting aggregations in Canberra as described elsewhere, with only small colonies consisting of a single or just a few nests. Characteristic comb-cutting behavior of the species was observed but this did not result in complete nest division as recorded from coastal populations. [ABSTRACT FROM AUTHOR]

Using demography data for the primitively eusocial wasp Ropalidia fasciata collected at 10 survey stations over 5 years, the effects of foundress group size (FGS) on colony survival rate and production of progeny were examined. The distribution pattern for the frequency of nests established by different numbers of foundresses fit a 0-truncated negative binomial distribution. The rate of nest failure up to the beginning of June decreased with FGS, and colony survival rate up to June and September increased with FGS. Although there were large variations among stations and years, the survival rate of colonies established by a single foundress (haplometrotic colonies) was significantly lower than that of colonies established by two or more foundresses (pleometrotic colonies). The number of new adults that emerged per colony up to the end of July increased with FGS, but there was no significant correlation between number of new adults per foundress and FGS. The number of potential foundresses produced per colony tended to increase with FGS, but there was no significant difference among the values produced per foundress for the three FGS categories. The percentage parasitism by an ichneumon parasitoid, Arthula formosana, tended to be higher in colonies established by a small number of foundresses. The relation between FGS and the productivity of the new foundresses was not statistically significant, suggesting that independent founding may be a better strategy for future subordinate foundresses. However, the long colony life span (mean 100 days, maximum 240 days) as compared with the shorter life span of foundresses (40 or 50 days) may be a good condition for the coexistence of many egg-layers in a colony. [ABSTRACT FROM AUTHOR]

Only two out of 959 pre-emergence colonies of the paper wasp Polistes snelleni de Saussure surveyed between 1989 and 1996 in Sapporo, northern Japan, were found to be two-foundress colonies, and the others were single-foundress colonies. The two foundresses in one of the two colonies showed neither aggressive dominance behavior nor clear division of labor between them during a total of approximately 30 h in the first half of the pre-emergence stage. Although both of the foundresses foraged for pulp and laid eggs, only one foundress foraged for prey and delivered it to the other. [ABSTRACT FROM AUTHOR]

During the past 15 years in the Ina Valley, Japan, mature fifth instar larvae of the yellow hornet, Vespa simillima, have been occasionally ejected from colonies during September. During 2005, this unusual behavior was particularly widespread, and collection of several V. simillima colonies confirmed that very few fifth instar larvae were present. When compared with an average colony, constructed from 41 colonies collected 20 years previously, colonies in 2005 had 80% fewer fifth instar larvae, despite queen egg-laying rates remaining similar. It may be that the amount of food provided to the larvae by workers is less than the amount of larval secretions received by workers, which is causing the larvae to become emaciated and preventing them from pupating. This phenomenon normally occurs naturally at the end of the colony cycle in November, when prey abundance decreases and larval secretions or other sources of carbohydrates, for example from ripe fruit, tree sap, or aphid secretions, are needed by sexuals to build up fat reserves. However, another possibility is that the unexplained appearance of this phenomenon in September, which is causing colonies to collapse without producing any or very few sexuals, is due to foragers feeding the larvae prey that are contaminated with insect growth regulators, via pesticides, which are known to prevent successful pupation. [ABSTRACT FROM AUTHOR]

Nineteen species of the paper wasp genus Ropalidia are recorded from Vietnam, of which three are new records for Vietnam. A key to all of the species, distribution records and taxonomic remarks are given. New synonymies proposed are: Ropalidia bicolorata parvula van der Vecht, 1962, under R. bicolorata van der Vecht, 1962; R. hongkongensis juncta van der Vecht, 1941, under R. hongkongensis (de Saussure, 1854); Icaria jucunda Cameron, 1898, and R. marginata sundaica van der Vecht, 1941, under R. marginata (Lepeletier, 1836); R. rufocollaris atrata van der Vecht, 1941, under R. rufocollaris (Cameron, 1900); and R. stigma rufa van der Vecht, 1941 and R. stigma nigrolineata van der Vecht, 1962, under R. stigma (Smith, 1858). [ABSTRACT FROM AUTHOR]

The taxonomy of the Australian species of twoRopalidiaspecies groups, theR. stigmagroup andR. variegatagroup, is revised and their distribution patterns are discussed. Two species in theR. stigmagroup (R. darwiniandR. elegantula), and four species in theR. variegatagroup (R. flavinoda,R. gregaria,R. mutabilisandR. revolutionalis) are recognized in Australia, with a new synonymy ofR. mutabilis torresianaRichards, 1978, underR. gregaria(de Saussure, 1854).Icaria torridaSmith, 1863, from Seram Island is synonymized withR. unicolor(Smith, 1859). [ABSTRACT FROM AUTHOR]

Mating structure and genetic relatedness among gynes (potential reproductive females) of the paper waspPolistes snelleniwere investigated using DNA microsatellite markers. All colonies had one foundress inseminated by a single male, and no sign of inbreeding was detected. The mean genetic relatedness among gynes was 0.734 ± 0.028 (SE), which is not significantly different from the expected value of 0.75 for full sisters. [ABSTRACT FROM AUTHOR]

We conducted a series of demographic studies of the primitively eusocial waspRopalidia fasciatain Okinawa, a subtropical part of Japan, and found the following. The colony cycle of this wasp is annual, spanning from April to November or even December; this is longer than the colony cycles of other temperate polistine wasps so far reported. The survival rate of the marked foundresses was 40% to June, dropping to 1.4% by September. These survival rates are similar to other subtropical and tropical species. Most females that emerged in November were probably second generation adults (progeny of the original foundresses), which would participate in founding nests in the following spring. These facts indicate thatR. fasciatain Okinawa is at least partially bivoltine. Survival of a nest to September was 10–20%; however, because a failed nest is often rebuilt, survival of the colony to September was as high as 50%. The mean number of new foundresses produced per foundress was 7.5, and their overwintering survival was 16%. Hence, a single foundress produced, on average, 1.2 progeny foundresses to the following year. Density dependence was shown in the rate at which the progeny foundresses were produced. These results explain the remarkable stability of nest densities from year to year in the area. The above results reveal thatR. fasciatain Okinawa shares many demographic characteristics with other primitively eusocial wasps, particularly year-to-year stability of nest density and a long colony cycle. [ABSTRACT FROM AUTHOR]

The relationship between reproductive status and body size in foundresses of Ropalidia plebeiana, an Australian endemic paper wasp forming huge aggregations of nests, was examined. Foundresses with developed ovaries (laying foundresses) in multifoundress colonies tended to be larger than foundresses in single-foundress colonies and foundresses with undeveloped ovaries (non-laying foundresses). However, the laying foundress was not always the largest of the foundresses in a colony. Body shape in foundresses varied according to simple allometric growth, while foundresses and first brood females diverged in their growth parameters in the preimaginal stage. [ABSTRACT FROM AUTHOR]

Abstract Mating frequency of Vespa analis queens and the genetic relatedness of their workers was analyzed by DNA microsatellite genotyping. Of 20 colonies studied, 18 had a queen inseminated by a single male and two had queens each inseminated by two males. The estimated effective number of matings was 1.05 ± 0.037 (mean ± SE), with 75–85% of the offspring of the two multiply mated queens sired by a single male. The pedigree relatedness between nestmate workers averaged over the 20 colonies was estimated to be 0.74 ± 0.008, almost identical to the predicted value of 0.75 for colonies headed by a singly mated queen. Multiple matrilines; that is, the presence of workers not related to the current queens, were detected in six colonies, suggesting that queen replacement occurred via usurpation of the founding queens in these six colonies. These results demonstrate that the kin structure of V. analis is similar to that reported in other vespid species. [ABSTRACT FROM AUTHOR]

Abstract Morphological differences between queens and workers in an Australian swarm-founding paper wasp, Ropalidia romandi , were examined, providing detailed information on the nature of morphological caste differences in swarm-founding Ropalidia for the first time. Queens and workers differed in overall size and had divergent shapes, but differences were not always significant. In colonies in which queen–worker dimorphism was distinct, while the head width of queens was nearly the same as that of workers, queens were significantly larger in measures on the metasoma than workers. Plotting of metasomal variables against the mesosomal length and analysis of covariance showed that queen–worker morphological differentiation in R. romandi cannot be explained by simple linear allometric growth, suggesting that the two castes diverge in their growth parameters in the preadult stage. The pattern of morphological caste difference varied among colonies or was colony specific; there was no clear correlation between caste differences and colony cycle progression. These results suggest that morphological caste differences in R. romandi are determined genetically or by interactions between genetic background and intrinsic factors and/or external conditions. [ABSTRACT FROM AUTHOR]

Presents a correction on the article about Ropalidia plebeiana, an Australian wasp forming nest aggregations published in an issue of the journal "Entomological Science."