Search

Several species of spider mites construct silk nests on leaf surfaces wherein they develop and reproduce (web-nesting species). Nesting patterns and behaviour of spider mites are related to predator avoidance, but the study of their influence on predatory fauna has been limited to species of a few genera. The present study investigates the occurrence of predators of Schizotetranychus brevisetosus, which make web nests and attack some predators, on evergreen oak in Kochi Prefecture, Japan. Of the total individual predators observed (n = 129), the highest proportion (38%) consisted of rove beetles Holobus spp. (Coleoptera: Staphylinidae), which are nest intruders and prey on mites at all stages of development. The second most abundant predators (26%) were Anystis spp. (Acari: Anystidae), which capture mites outside the nest. The common predators Phytoseiidae spp. (Acari) accounted for only 15% and were mostly found in hibernation. Other predators were rare, except for egg-eating Agistemus spp. (Acari: Stigmaeidae) (13%). The findings suggest that web nests and anti-predatory behaviours may bias the predatory fauna toward species that can cope with these anti-predatory strategies. [ABSTRACT FROM AUTHOR]

Differences in the time of occurrence of both sexes of adult ladybirds, which reflect differences in the longevity and reproductive strategies of the sexes, is important from the perspective of applied entomology, including biological control, as well as basic entomology. Nevertheless, there is little field census data on this topic. We investigated the seasonal occurrence of both sexes of Cheilomenes sexmaculata (Fabricius) in Osaka City, central Japan, from 2003 to 2011. Female adults tended to appear earlier than males after hibernation or aestivation. That males never appeared earlier than females during the nine year period of this study indicate that protogyny occurs after hibernation and aestivation in this species. [ABSTRACT FROM AUTHOR]

Small rodents living in forests use various spaces on trees for arboreal activities such as daily rest, hibernation, foraging, sheltering, roosting, and nesting. To investigate the differences in arboreal activity between two sympatric cavity-nesting rodents, Glirulus japonicus and Apodemus argenteus, we compared the frequencies of nest box use by these species at three different heights, and surveyed tree cavities. We observed that G. japonicus used nest boxes mounted at a relatively greater height most frequently, whereas A. argenteus used boxes placed at lower heights. Glirulus japonicus used all nest boxes for resting, while A. argenteus used most nest boxes for food hoarding. The tree cavities that were used by G. japonicus were located significantly higher than those used by A. argenteus. In a multinomial logistic regression analysis, height at which a cavity was located was identified as factor affecting frequency of cavity use. [ABSTRACT FROM AUTHOR]

Bombus terrestris (L.) (Hymenoptera: Apidae, Apinae, Bombini) has been introduced to Japan and became the dominant bumblebee in some areas, replacing native species. To implement an effective eradication program, the attributes responsible for establishment of the species must be better understood. Because body size has frequently been related to reproductive success in female insects, I examined the effect of B. terrestris queen size during hibernation, nest founding, and reproduction stages. Queens exhibited clear variation in size. Foundresses were significantly larger than gynes, indicating that larger queens may have an advantage over smaller ones in surviving hibernation. The over-representation of queens with pollen at larger sizes suggested that larger queens may also have an advantage over smaller ones in nest founding. On the other hand, foundress size was not significantly associated with reproductive output. The number of collected foundresses in this study was not sufficient to draw a clear conclusion but factors other than foundress size may also play an important role in determining reproduction. In addition, gyne size increased significantly during the 4-year survey. Because large queens have an advantage during hibernation, increased body size may increase the number of hibernating queens that survive, allowing them to outcompete native bumblebees. [ABSTRACT FROM AUTHOR]

At 17 localities in Japan, 71–81% of overwintering adult females of the solitary bee Ceratina flavipes mated before hibernation. The occurrence of males with inseminated females in their natal nests suggested the possible occurrence of inbreeding. Therefore, we examined the seasonal trends of inbreeding coefficients, calculated by comparing the band patterns of microsatellite DNA between a female and her mating partners (indicated by sperm in her spermatheca). The mean coefficient of inbreeding was 0.80 on 25 August and 0.60 on 1 November versus 0.31 on 5 June and 0.38 on 28 June. These results demonstrate a tendency towards inbreeding before winter and towards outbreeding during dispersal after hibernation. [ABSTRACT FROM AUTHOR]

The predation pressure of the greater horseshoe bat, Rhinolophus ferrumequinum, on the diapausing population of the noctuid moth, Goniocraspidum preyeri, was examined at an abandoned mine in central Japan. These bats did not prey on the moths in summer. The number of moths preyed on was largest in March. More than 60% of the diapausing moths were eaten by only three or four bats, which accounted for over 90% of all the moth deaths. This moth was an important source of food at the end of the hibernating period when the bat had already used most of its stored subcutaneous fat. The predation on G. preyeri may have raised the overwintering success rate of R. ferrumequinum. [ABSTRACT FROM AUTHOR]

Although females of Ceratina flavipes are believed to be inseminated in spring on Honshu Island, Japan, 100% of the females were inseminated before hibernation on Ishikari Coast, northernmost Japan. Because most, if not all, of the males also overwintered with the females, this prehibernal insemination may be a local event. In the hibernal season, females were more frequently alone in nests than males, whereas the sex ratio in their main habitat was almost 1:1, suggesting that prehibernal dispersal is more frequent in females, but that the dispersal distance is shorter than previously reported. [ABSTRACT FROM AUTHOR]

• Hibernating behaviors of household PCs were surveyed. • Hibernation function was estimated and the hibernated PC stock was projected. • Routes and services for PC discharge were also surveyed and discussed. • The hibernating reasons differed by hibernating period. • Many consumers misunderstand the current PC collection scheme in Japan. The recovery of electric and electronic waste is one of the key issues in developing a circular society. In Japan, the Act on Promotion of Recycling of Small Waste Electrical and Electronic Equipment was established in 2012 and the collection of small electronic devices has been promoted. However, the collected amount has not increased, and hibernating behaviors are observed. In this study, we focused on household personal computers (PCs), of which the hibernated stock and hibernating behaviors have not previously been analyzed in detail. We conducted a questionnaire survey and obtained data concerning hibernated PCs in households. Based on the data of hibernating period distribution, the hibernation function was estimated and the hibernated PC stock was projected. In addition, the hibernation reasons and possible services that could encourage smooth PC disposal were analyzed and discussed. People kept PCs for less than one year because of using them in the future, while they hibernated PCs 1-5 years because of bothersome feelings and less knowledge about disposal ways and data erasing. The results about actually disposed and possible disposal routes indicated that a certain number of consumers misunderstand or do not know the current PC collection scheme in Japan. The preferred services by respondents also indicated that enforcement of the collection schemes themselves and more intensive public awareness activities are needed to improve the smooth discharge of unused PCs. Image, graphical abstract [ABSTRACT FROM AUTHOR]

AstroNewt experiment explores the effects of earth gravity on the early development of Japanese red-bellied newt, Cynops pyrrhogaster. Since female newts keep spermatophore in cloaca, fertilized eggs could be obtained without mating. Fertilization of newt's egg occurs just prior to spawning, so that gonadotrophic cues applied to females in orbit leads to laying eggs fertilized just in space. A property of newt being kept in hibernation at low temperature may be of great help for the space experiment carried out with much limited resources. A general outline of the AstroNewt project is shown here in addition to some technical advances for the development of the project. Experimental schemes of two space experiments (IML-2 in summer 1994 and unmanned SFU at the beginning of 1995) are also shown.