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Temperature characteristics in paper models of Polistes wasp nests with various numbers (N = 7, 19, 37, or 61 cells) and lengths (L = 10–50 mm) of cells were measured in the field. Temperature distribution in a N61L50 model showed that the central cell provided the best thermal conditions in terms of gained temperature and its fluctuation. The mean temperature excess (difference between cell and ambient temperatures) observed in the diel trial 1 (L50 models with different cell numbers) was 1.5°C in N7 model and 2.3°C in N61, whereas in trial 2 (N37 models with different cell lengths) it was 0.6°C in the L10 model (with 10-mm-long cells) and 2.4°C in L50. In these trials, models with larger numbers of cells or longer cells attained a higher temperature. It seemed that length was more effective in gaining higher maximum temperature than the number of cells. By their heat insulation effect, peripheral cell rings ameliorated the temperature fluctuation in cells at the central part of the comb. Models with more and longer cells maintained temperature slightly higher than the ambient level even during the nighttime.

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.

This study focused on how a decrease in prey availability affected the development of aP. dominulus Christ colony. Nutritional oophagy and larval development were parameters found to be most directly affected. The more indirect effects on the growth of the nest and on offspring production were also analyzed.

Intraspecific nest usurpation by foundresses was studied in 2 haplometrotic (solitary founding) species of different subgenera,Polistes (P.) riparius andP. (Polistella) snelleni, in areas where they cohabited. The overall probability for a nest to be usurped by a foreign foundress during the season was about twice as large inP. snelleni as inP. riparius. In both, however, probability of usurpation was largest on late pre-emergence nests, or in late June and early July. InP. riparius, all the usurpers of known origins were those foundresses that had lost their pre-emergence nests to destruction probably by some vertebrates; inP. snelleni, some usurpers had the same history as above, while the others had lost many of all larvae to predation by unknown agents before worker emergence. Usurpers of both species destroyed eggs and younger larvae to much greater extents than older larvae or pupae, and they produced fewer numbers of reproductives in comparison with non-usurping foundresses. We concluded that usurpation behavior has been maintained despite its relatively low productivity because renesting would lead to even lower or no reproductive production.

The behavior of workers on 2 nests of the Japanese paper wasp,Polistes jadwigae, was recorded on video tape. Young workers performed pulp collection more frequently than middle-aged and old workers, while foraging of flesh (prey) was done mainly by middle-aged workers. Of the 26 behavioral categories, 7 showed negative, 2 concave, and 1 convex relationship to the workers age. Using behavioral profiles, workers could be classified into 3 age groups: 1) young workers (younger than 10 days old, active intranidal workers), 2) middle-aged workers (11–25 days old, extranidal workers) and 3) old workers (older than 26 days old, ‘idlers’). Idlers engaged in foraging and larval feeding significantly less frequency than the young and middle-aged workers, but they performed alerting toward many alien objects. Task specialization among workers irrespective of age polyethism was also suggested.

Worker reproduction and related behavior in 2 orphan colonies ofPolistes jadwigae, one of which had been maintained by a queen and 5 artificially introduced alien workers, were observed. After the queen loss, a dominance hierarchy was established among workers, and several workers laid eggs without physical interference from other workers. Only males emerged from worker-laid eggs, however, a few new queens were produced from queen-laid eggs. Investment sex ratio of queenright (=normal) colonies (0.27) fell between the 2 theoretical values, corresponding to worker control (0.20 or 0.18) and queen control (0.48 or 0.46) of the sex ratio, both being calculated by considering the excess of males produced in the orphan colonies.

In southern Taiwan, most colonies (13 out of 14) ofParapolybia varia were founded by multiple females. Several females were present at the founding and increased up to 25 about one week after it. Observations on 2 pre-emergence colonies (in a total of 21 h) and those on 4 postemergence colonies (in 62 h) revealed the following facts: In the pre-emergence period, the top-ranking female dominated all others like a despot. Some females attending from the founding also dominated other females who joined later. Interactions among females gradually decreased in frequency after the founding and became milder. The top-dominant rarely left the nest and monopolized most of ovipositions by physically disturbing the subordinates' attempts to oviposit. Differential oophagy was not observed even when the subordinates succeeded in laying (6 cases). After the emergence of workers, the subordinate associates gradually disappeared and the colonies became monogynous (one egg-layer or queen per colony). Monogyny was also confirmed in October on 3 big colonies which had already produced reproductive forms. Eighty-six percent of females (n=50) taken from nests of early stage containing nothing or eggs alone were inseminated and 66% of them had well developed ovaries, while 90% of those (n=20) from more developed nests containing mature larvae and/or pupae were inseminated and only 25% had developed ovaries. This suggests that the ovaries of the subordinates had possibly, though not completely, degenerated through dominance interactions.

Social interactions amongRopalidia plebeiana females on a nest were observed in Brisbane, Australia. Although a single female (queen-like female) tended to remain on the nest most of the time, and received food most frequently from females which returned from foraging trips, no dominance/aggressive acts were directed by her to regular nestmates. When a possibly alien female tried to join the female group, however, the queen-like female attacked this female strongly. The frequency of these attacks gradually decreased and the newcomer was accepted as a regular member by the eighth day. The attacked female showed a special, possibly ritualized, posture and this seemed to have reduced the frequency of attacks.

Behavioral catalogues, transition matrices between 2 consecutive behavioral acts, and the frequency distribution of time spent in each behavioral act were described for queens and workers of a Japanese paper wasp,Polistes chinensis antennalis in the ergonomic stage (the period from the emergence of the first worker to the emergenece of the first reproductive). The results were; (1) The whole behavior repertoire of queens was completely included in that of workers. Workers oviposited frequently in queen-right colonies. (2) The proportion of off-nest activities to the number of total acts for workers was higher than that for queens. The proportion of time spent off the nest in workers was 5 times as high as that in queens. (3) There was no significant difference in the proportion of number of oviposition to the total number of acts between queens and workers. The oviposition rate was 0.06 eggs/h for workers and 0.37 eggs/h for queens. Queens made more dominance behavior and workers more subordinated behavior. Queens made abdomen wagging more frequently than workers. (4) For behavioral acts common in both queens and workers, the mean duration of a specific act was approximately equal for both. The mean duration of unsuccessful flesh collection for workers was 3.4 times as longs as that for queens. Workers did not search for flesh in 10.1% of duration of flesh collections in the field. (5) The pattern of transitions between 2 consecutive behavioral acts in workers was similar to that in queens. (6) Alien workers approaching a nest with a load were more often accepted by the nest occupants than alien workers with no load. Alien workers with no load were not accepted as often as a legitimate nestmates with no load. The reproductive division of labor between queens and workers inP. chinesis antennalis was incomplete. This suggests worker-queen conflict in different reproductive strategies among colony members. Several behaviors were consistent with the view that they are the behavioral expression of this conflict.

Analysis of the behavior of foundresses of a Japanese paper wasp,Polistes chinensis antennalis Perez, was made to clarify the patterns of decision making. It was found that: (1) Foundresses postponed the next activity off the nest after being attacked by a foundress from another colony. (2) After a spiral flight, the frequency of subsequent spiral flights and patrol flights around the nest increased. (3) Following successful flesh collection, the frequency of flesh collection increased. (4) Following successful flesh collection, the time spent for a single trip of flesh collection increased. It was concluded thatP. chinensis antennalis foundresses solve their dilemma between the need of nest defence and resource gathering by decision making based on intraspecific attacks and the intake of the most difficult resource to obtain.

Field studies showed that the percentage of foundation by multiple foundresses was remarkably high (34.5%) inRopalidia fasciata in Okinawa. Although one of the foundresses of the association usually remained on the nest and others tended to do extranidal activities, the dominance-subordination relation among cofoundresses seemed to be far milder than that reported inPolistes spp. of Europe and North America. Dominance relation sometimes reversed. All the foundresses could receive a share of food and feed larvae. It was suggested that a large risk of parasitism and predation should favour the trait to join foundress associations inR. fasciata.

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.