Social behaviour of the australian paper wasp,Ropalidia revolutionalis (de Saussure) (Hymenoptera: Vespidae)

Social behaviour ofRopalidia revolutionalis (de Saussure) was observed in Brisbane and Townsville. Nests were, as a rule, founded by association of females. Each nest began as a single comb but, after the emergence of progeny adults, satellite combs were constructed near the original comb. During the pre-emergence (single-comb) stage, each colony had a single egg-layer, despite the rare occurrence of intranidal dominance acts among female wasps. When colonies had reached the multiple-comb stage, the frequency and intensity of intranidal dominance-aggressive acts rose to a high level, comparable to those of typically aggressive colonies of e.g.Polistes canadensis in Panama. Colonies appeared to be still functionally haplometrotic during the early phase of multiple-comb stage, but several potential egg-layers were present as colony size increased. Dominant females often performed wing vibration, rapid runs between combs and tended to sit on the largest comb, whilst subordinate females tended to sit on smaller combs.     

On “intercolonial” cannibalism in Japanese paper wasps,Polistes chinensis antennalis Pérez andP. Jadwigae dalla torre (hymenoptera: Vespidae)

Summary Foundresses of two species of Japanese paper wasps,Polistes chinensis antennalis andP. jadwigae, attacked other colonies of the same species. A foundress ofP. chinensis antennalis visited two nests of the same species, and ate larvae from them, while two foundresses ofP. jadwigae each visited a nest of the same species, eating larvae and pupae even when the foundress of the attacked nest was on her nest. In addition, a foundress ofP. jadwigae distributed flesh balls thus obtained among their larvae. Discussion was made on the adaptive significance of the inter-colonial cannibalism. It was considered that, at first, it increases the foraging efficiency and secondly it plays a role in regulating population density.     

Recommendations for the use of species diversity indices with reference to a recently published article as an example

There are some recommendations for the use of species diversity indices in a paper recently published in this journal by M. Ohsawa on the species richness and composition of weevils in five forest types in the middle region of Japan. Because several factors, such as small sample size, calculation of Simpson’s diversity index by the use of the original equation of Simpson’s measure of concentration D, and a weak point in the Shannon–Wiener diversity index H′, may have led to biased estimates, I recalculated these indices using combined species diversity values of the five forest types. As the general tendencies of 1−D and H′ values calculated here were similar to those in Ohsawa’s paper, there is no need to propose any change to his view. However, these recalculated diversity indices indicated that they are values which are more suitable for use. It should be noted that the characteristics and weak point associated with the diversity indices need to be taken into account in future studies.     

The growth form of populations in some aphids,with special reference to the relation between population density and the movements

---

National Institute of Agricultural Sciences     

Population dynamics of the chestnut gall-wasp,Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae)

Summary As a part of serial study on population dynamics of the chestnut gall-wasp,Dryocosmus kuriphilus, analyses of the distribution of eggs, gall-cells and emergent holes were made from the statistical point of view. Many of distributions of the eggs per bud could be described by the truncated Poisson, but some cases showed slight overdispersion than expected by chance. Because of no linear increase of with increasing (expected mean for complete sample), however, the truncated negative binomial seemed to be not so available for whole series. Distributions of the gall-cells and the emergent holes were, on the other hand, well described by the truncated Poisson distribution when the observed frequency was calculated for respective trees. Negative-binomial tendency found in distributions from some stations consisted of a certain number of trees would be resulted from mixture of Poisson populations with different means. Random or slightly concentrated oviposition and random mortality within galls was thus supposed for future study unless the proof favouring other distribution models would appear.     

Proteome of the phytopathogen <Emphasis Type="Italic">Xanthomonas citri</Emphasis> subsp. <Emphasis Type="Italic">citri</Emphasis>: a global expression profile

Background  

Citrus canker is a disease caused by Xantomonas citri subsp.citri (Xac), and has emerged as one of the major threats to the worldwide citrus crop because it affects all commercial citrus varieties, decreases the production and quality of the fruits and can spread rapidly in citrus growing areas. In this work, the first proteome of Xac was analyzed using two methodologies, two-dimensional liquid chromatography (2D LC) and tandem mass spectrometry (MS/MS).     

Social behaviour of two primitively eusocial wasps,Ropalidia sp. nr.variegata andR. gregaria gregaria (Hymenoptera: Vespidae) in the Northern Territory,Australia, with special reference to task specialization and mating inhibition

Social behaviour of females of the Australian paper wasps,Ropalidia sp. nr.variegata (V) andR. gregaria gregaria (G) was observed near Darwin, the Northern Territory, Australia. Both species constructed multiple combs after the emergence of the first progeny. Frequency of intranidal dominance acts in speciesV on the post-emergence nests was significantly higher than that on the pre-emergence nests, while the frequency was constantly high in speciesG throughout the pre- and post- emergence periods. Some females ofG were specialized, at least on single days, to perform the particular task of water collection. In both species the dominant female tended to occupy the largest comb and subordinate females smaller combs. InG, not only the top-ranked female but also low-ranked ones oviposited, and a small proportion of eggs laid by the latter survived at least until the end of observation. InV, each colony had only 1 inseminated female which had highly developed ovaries, suggesting that subordinate females do not mate despite the presence of males. Such a limitation of mating to a single female in a colony has not been described previously in primitively eusocial wasps.