We investigated distribution and sexual composition of founding associations of Reticulitermes kanmonensis, the Japanese subterranean termite, which occurs only in the Kanmon area. These properties are discussed in relation to body size and mitochondrial genotype of the dealates. The founding colonies showed a highly aggregated distribution with a 'hot spot' of colony founding; however, mitochondrial haplotypes of the dealates suggested random mating. Monogamous colonies were predominant, but solitary colonies and colonies with two females and/or males also occurred. Paired dealates tended to be larger than solitary founders, suggesting that both sexes were under sexual selection related to body size.

Observations of the flowering phenology and measurements of the heights of understory herbaceous plants were made in a cool temperate deciduous forest, where light availability is relatively low and fluctuates markedly through the year, and it is too cold for many plants to grow in winter. Ninety-one species were recorded between April and October. The number of flowering species as a function of date showed a bimodal distribution. The plants flowering in spring and those flowering from late summer to early autumn each accounted for about 40% of the number of species. The plants that flowered in spring were smaller than those that flowered later in the season. The springflowering plants would produce flower buds in the previous growing season, as the time from the appearance of the aerial part to flowering was transient. Some species completed their main life history events during the spring as spring ephemerals. The small sizes in these species may result from bud formation in the previous 8eason and/or the short period of growth. The plants that flowered in late summer and early autumn, by contrast, were large. These plants should have relatively long periods of vegetative growth and flower at the end of the growing season using matter produced in that year. A long vegetative growth period would tend to make plants firm and/or large. It was suggested that flowering phenology was separated into two periods by the climatic and environmental constraints of a cool temperate deciduous forest.Plant flowering phenology has a close relationship with life history strategy and is affected by various factors including climatic conditions, habitat environments, and interactions with other organisms (Rathcke and Lacey 1985). In a given biome, the flowering phenology pattern of a plant community through the year shows trends that reflect the constraints of climatic factors and habitat conditions; many herbaceous plants flower immediately after the wet season in South India (Sivaraj and Krishnamurthy 1989), dry conditions caused by low river levels trigger flowering in East African riverine forests (Kinnaird 1992), flowering phenology is constrained by a cool and short growing season in the Arctic (Thbhallsd6ttir 1998), and so on.The light regime in a habitat is considered to affect the production of matter in plants. On a forest floor, light availability is relatively low. Especially in a cool temperate deciduous forest, light availability fluctuates markedly through the year and many plants are unable to grow in winter. Uemura (1994) tested leaf phenology patterns in a forest understory and suggested that leaf habits have relationships with the light regime of habitats and climatic conditions. Because reproduction is limited by matter production, the flowering pattern of the understory herb community may be also related to climatic and environmental conditions. However, only a few studies have focussed on the flowering phenology of the understory herbaceous community in a temperate deciduous forest in terms of habitat condi...

Old-growth forests consist of various types of small patches that reflect their own gap-forming process, which includes changes in environmental conditions occurring over several decades. We reconstructed the gap-forming processes that had occurred during a 40-year period for eight representative patches of an oldgrowth evergreen broad-leaved forest in Japan, and examined the current community structure. The selected patches were based on (1) changes in canopy heights estimated from aerial photographs taken in four different years, (2) long-term ecological research (LTER) monitoring records, and (3) a recent field survey, so that they sufficiently covered characteristic gap-forming processes such as a new gap, an old gap and consistently closed canopy. Height and diameter at breast height (DBH) were measured on all living trees taller than 1.3 m. In their height distributions, currently almost closed patches that were open in 1966 show a rotated sigmoid, whereas their DBH distributions are an inverse J-shape. In contrast, patches that have been consistently under a closed canopy exhibit gentle inverse J-shapes for both distributions. For species composition, there are no clear contrasts associated with the past gap-forming processes except for the existence of fast-growing deciduous species in large currently open patches. Our results suggested that the variation in several decades of gap-forming processes played a central role in the high patch diversity and the complex patch mosaic of the forest. Diverse gap-forming processes created microenvironmental heterogeneity both vertically and horizontally, and contributed to the maintenance of the species-rich, warm-temperate old-growth forest.

Pertya triloba (Asteraceae) is a perennial herb growing in the understory of deciduous broad‐leaved forests in central Japan. Its capitulum consists of a single floret that differs from those of most other Asteraceae species. A bagging experiment clearly showed that breeding of P. triloba required cross‐pollination. By using female fertility as a measure of pollination success, the effect of an attractive floral display on the threshold plant size for flowering in P. triloba was surveyed. The number of florets per plant in a P. triloba population was artificially adjusted between one and 30. In both control plants and experimental plants with adjusted floret number, the seed set increased with an increase in the number of florets per plant and became constant (60%) when the floret number per plant was more than 10. Thus, the number of florets per plant has an important role in attracting pollinators, and more than 10 florets per plant must be the effective floral display size. In the P. triloba population, 98.5% of the flowering plants had 10 or more flowers. The effective floral display size might be determined through the mutual relationship between plants and pollinators. The number of florets per plant increased with an increase in the plant leaf area. Therefore, the threshold plant size for flowering might be determined by the productivity needed to support an attractive floral display.

When we calculate mortality along a gradient such as size, dividing into size classes and calculating rates for every class often involves a trade-off: fine class intervals produce fluctuating rates along the gradient, whereas broad ones may miss some trends within an interval. The same trade-off occurs when we want to illustrate size distribution by a histogram. This paper introduces nonparametric methods, published in a statistical journal, into forest ecology, in which the fineclass strategy is used in an extreme way: (1) a smoothly changing pattern is approximated by a fine step function, (2) the goodness-of-fit to the data and the smoothness along the gradient are formulated as a weighting sum within a Bayesian framework, (3) the Akaike Bayesian Information Criterion (ABIC) selects the weighting system that most appropriately balances the two demands, and (4) the values of the step function are optimized by the maximum likelihood method. The nonparametric estimates enable us to represent various patterns visually and, unlike parametric modeling, calculations do not demand the determination of a functional form. Mortality and size distribution analyses were conducted on 12-year forest tree monitoring data from a 4 ha permanent plot in an old-growth warmtemperate evergreen broad-leaved forest in Japan. From trees of 11 evergreen species with a diameter at breast height (DBH) greater than 5 cm, we found three types of trend with increasing DBH: decreasing, ladle-shaped and constant mortality. These patterns reflect variations in life history particular to each species.