Queen condition,mating frequency,queen loss,and levels of worker reproduction in the hornets Vespa affinis and V. simillima

Abstract 1. Mature queens of the hornet Vespa affinis are unusual in that they lose all their body hair and wings. This has been used as evidence for matricide in hornets. Factors favouring matricide such as low paternity and long annual lifecycle are present in most hornets. 2. We determined paternity in V. affinis and compared queen condition, levels of queen loss, and worker reproduction in 163 V. affinis and 63 V. simillima colonies. These two species have very similar lifecycles and colony sizes, but different paternities (1.3 vs 2.4). Furthermore, in queen‐right V. affinis colonies small proportions (4%) of reproductive workers were present, whereas in queen‐right V. simillima colonies no reproductive workers were detected. 3. Despite these differences, queen damage in both species was influenced predominantly by her age and in V. affinis was not influenced by presence of reproductive workers. 4. The number of queen‐less V. simillima (9/63 = 14%) and V. affinis (28/163 = 17%) colonies were also not significantly different (P = 0.8). Therefore, queen damage and proportions of queen‐less colonies were not linked making it a poor indicator of matricide. 5. It is proposed that graded control of sexual and worker production in wasps and hornets prevents a situation where kin‐selected matricide is ever favoured.     

Late Jurassic decapod crustaceans from northeast Japan

Abstract: Astacidean and thalassinidean macrurans (Glyphea sp., ?Eryma sp. and Protaxius sp.) and a new longodromitid crab, Planoprosopon kashimaensis, are recorded from the Upper Jurassic (upper Kimmeridgian to lower Tithonian) of Fukushima Prefecture, northeast Japan. Material was collected from the Tatenosawa Sandstone Member of the Nakanosawa Formation, Somanakamura Group, from which abundant Tethyan‐type marine invertebrates are known. Planoprosopon kashimaensis sp. nov. closely resembles P. heydeni (von Meyer), a common form in the Upper Jurassic of the Tethyan realm in Europe, and represents the oldest record of a brachyuran from the circum‐Pacific region. Similarities to contemporaneous decapod assemblages in southern Germany indicate that closely comparable, parallel decapod faunas in the Tethyan realm, inclusive of brachyurans, had already been established in the western circum‐Pacific region by the Late Jurassic.     

Reproductivity of early males of the temperate paper wasp Polistes rothneyi iwatai

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.     

Mating structure and genetic relatedness among gynes in the primitively eusocial wasp Polistes snelleni (Hymenoptera: Vespidae)

Mating structure and genetic relatedness among gynes (potential reproductive females) of the paper wasp Polistes snelleni were 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.     

Honeybee‐assisted wind pollination in bamboo Phyllostachys nidularia (Bambusoideae: Poaceae)?

Floral syndromes and pollination of three species of Phyllostachys bamboos were studied in Central China in 1999 and 2000. All were protogynous. Stigmas were receptive and had pollen deposited on them 2 days before anther dehiscence. The period of anthesis in the three bamboos was 3 days. Individual pollen grains of the three species were similar in size (30–40 μm in diameter) and had features typical of wind-pollinated plants. The ratios of pollen to ovules (p/o ratio) in P . nidularia , P . heteroclada and P . nuda were 6500, 12 700 and 33 000, respectively. Mean pollen loads on each flower (one ovule) of these three species were 7.3, 8.8 and 9.4 grains, respectively. Pollen transfer in P . heteroclada and P . nuda depended on wind, and no flower visitors were seen in the field. However, in P . nidularia , Apis cerana Fab. was a frequent pollen collector observed from 1200 to 1330 h. The visits undertaken by thousands of honeybees resulted in a large number of pollen grains being released from the anthers in a short time (10–15 min) in one day, which accelerated and synchronized the release of pollen from the anthers that seemed to enhance the chance of pollination. Given that honeybees played an indirect role in pollen transfer this could partly explain the low p/o ratio in P . nidularia . Reviewing the literature, we found insect visits to flowers of bamboos were not infrequent phenomena. We suggest pollination efficiency should be considered as one selective factor in attempts to understand mast flowering in bamboo. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 1–7.