Population studies of Odonata have so far been carried out separately for either of the larval and the imagical periods. The survivorship curve of Odonata from egg to reproductive adult is reported probably for the first time in the present paper, which deals with a population of Cordulia aenea amurensis SELYS at Horai-numa near Sapporo. The curve drawn from the averaged data of the 1966-1973 year-classes shows that the mortality rate is higher during the early stages of the aquatic period than during the later stages (Type III, DEEVEY, 1947), and that the rate is lower in winter than in the other seasons. About 99.8% of the initial population (eggs laid) died during the aquatic period lasting five years, in which predation by Aeschna nigroflava MARTIN was regarded as a major cause of the deaths, based upon rearing experiments and miscellaneous observations. The number of mature adults arriving at the reproduction site was estimated at 0.07% of the initial population. A considerable stability was confirmed in the size of emerging population : the maximum size was 2.2 times the minimum one among the six year-classes. It is likely that this stability is caused by the switching of prey selection by predators (cf. MURDOCH, 1969) and/or the effect of refuge space from predators (cf. MACAN, 1974) during the aquatic period.
Effect of photoperiod on male egg production by foundresses of Polistes chinensis antennalis PEREZ (Hymenoptera, Vespidae) was investigated under five light conditions ranging from 12L : 12D to 16L : 8D. It was concluded that male egg production by foundresses was clearly affected by photoperiod and was much accelerated under the condition of short day length.
As the first step in the analysis on the vegetational zonation of three hygrophytes, Zizania latifolia, Phragmites australis and Miscanthus sacchariflorus, a year-long culture experiment was run twice in 1974 and in 1975. To investigate the effects of water levels on the development of new rhizomes, the following three plots with different water levels were set up : -15 cm (dry plot), -5 cm (wet plot) and +5 cm (fiooded plot) above the soil. M. sacchariflorus in the flooded plot developed many small new rhizomes in contrast with the few but larger ones which developed in the wet or dry plot. The small sized rhizomes failed to sprout buds in the following season. The maximum ratios of rhizome/total biomass at the end of the growing season were attained in the dry plot for Z. latifolia and M. sacchariflerus. The ventilation coefficient expressing the oxygen diffusion capacity through shoots was highest in Z. latifolia, followed by P. australis and then by M. sacchariflorus. The coefficient increased adaptively with soil moisture in all three species.
Light-photosynthesis curves for eleven rain forest tree species were determined in May-July 1972 and December 1973-March 1974 at Pasoh Forest Reserve, Negeri Sembilan, in Peninsular Malaysia. Tall emergent trees were classified into two groups according to their responses to light : one showed fairly high rates of net photosynthesis at light saturation (20-30 mgCO_2/dm^2hr) ("sun plant type"), and the other revealed lower rates (10-15 mgCO_2/dm^2hr) ("shade plant type"). The former group was represented by a single example of Shores leprosula, while the other species of Shorea, Dipterocarpus spp., etc. belonged to the latter group. The photosynthetic rate was also high in fast-growing secondary forest species such as Macaranga, Mallotus and Glochidion, though the light saturation and compensation points were reached at considerably low levels of light intensity.
A theoretical examination of pollen dispersal suggests that : (1) in a forested region containing about 40% Cryptomeria japonica trees, 5.0% Cryptomeria pollen is found ca. 10 km away from the source forest ; and (2) an increase to 5.0% from a lower percentage indicates the actual arrival of trees sparsely distributed in the forest within 500 m. After its initial arrival, the Cryptomeria forest shows a logistic increase under climatically near optimal growing conditions. The standard empirical equation for this increase is expressed by p=50.0/(1+14.16 e^<-0.0014t>), where p is Cryptomeria pollen percentage at time t (yr). Combined pollen frequencies against time that are obtained from six bogs become scattered at higher levels, since the carrying capacity for the population is variablea among these sites. However, sigmoid curves of the Cryptomeria increase toward respective asymptotes are essentially identical from the initial rise up to the 25% level. It normally takes about 1,000 years for pollen percentages to increase from 5% to 10%, and an additional 1,500 years to reach ca. 35%. The fact that Cryptomeria increases logistically implies indeed that even when its pollen percentage is low at the beginning of the rise, climatic conditions must already be favorable for maximum growth of the species.
Field observetions of marked Japanese long-tailed mice were made at the coniferous forest mingled with broad-leaved trees in Mie Prefecture for about one year. The tendencies of uses of holes, the home range sizes and overlapping areas between home ranges of this species were different according to sexes and ages ; Adult females and young had stronger tendencies to use one hole continuously than adult males ; The average home range size of adult males was larger than that of adult females, and that of young was smaller than that of adult females ; There were expansions of home ranges of both sexes during estrous, and reductions of home range sizes of females during sucking ; young mice expanded their home ranges with growth ; overlappings among home ranges of adult males were larger than those among adult females, and that between adults and young. Overlappings between adult males and females were large. The resident mice used plural holes in their home ranges. Home ranges of young were located in places where there were high densities of holes.
Freezing resistance of 45 species growing in Hokkaido University Forest, Tomakomai was assessed to study the ecological adaptation of plants to cold climates. Freezing resistance of most plant oragans increases from September to late-December and decreases from Feburuary to late-May. The aerial organs were hardier than the subterranean organs in most species examined. Phanerophytes were the hardiest and geophytes were the least hardy in the freezing resistance of dormant buds. In rhizomes and roots, hemicryptophytes growing in the road side were much hardier than those in the forest floor, and geophytes were the least hardy. These hardiness trends seem to correspond to the temperauture conditions surroundings the plant organs. On the other hand, little difference was found between hemicryptophytes in the road side and those in the forest floor, in the freezing resistance of dormant buds. These hardiness trends were still unchanged after hardening at -3℃ for 20 days from October to December. From these results, it seems that hardiness of the most plant organs is closely related to their life form and habitat.
The Tamagawa and the Takamatugawa are remarkably acidotrophic rivers ; the former is the largest and the latter is medium-sized among the tributaries of the Omonogawa River. The distribution of aquatic Phycomycetes and the amount of their zoospores, which is considered as an indicator of their potential growth, were investigated along the water-course of the Takamatugawa from June 1978 to May 1979 and the Tamagawa from June to December 1979. On the distribution of aquatic Phycomycetes in the Tamagawa, their floras in the upstream regions of the strong acid water (pH 2.7-3.8) were different from those in the downstream regions of the weak acid water (pH 4.6-6.7); i.e., Saprolegnia litoralis was dominant in the upstream regions of the strong acid water, while Achlya flagellata and Saprolegnia diclina were dominant in the downstream regions of the weak acid water. On the other hand, in the Takamatugawa, S. litoralis was dominant in all regions along the water-course (pH 2.6-4.0). S. litoralis is thought to be adapted to strong acid river. The amount of zoospores of aquatic Phycomycetes in these rivers was small in comparison with those in non-acid rivers (pH about 7.0). By tracing seasenal change, it is said that the amount of their zoospores decreases in summer.
Annual production rate of secondary phloem and bark biomass were studied in the five Cryptomeria japonica plantations located on Tanba Hill north of Kyoto. Five to eight sample trees in each stand were felied and measured by stratified clip technique. Growth of the phloem in stem and branch was measured with stem analysis technique on the basic research for the structure of an annual growth layer in secondary phloem of C. japonica carried out by M. MIYAGAWA et al. The proportional relationship between annual growth rate of the phloem in stem and leaf dry weight per tree was recognized on logarithmic coordinates and the single regression represents for all sample trees among five stands. The ratio of annual growth rate of the phloem to that of stem wood per tree tends to increase with decreasing stem wood growth. Annual production rate of the phloem ranged from 0.557 to 0.829 t ha^<-1>y^<-1> for stem and from 0.094 to 0.298 t ha^<-1>y^<-1> for branch. These values in stem accounted for 8.1-20.4% of biomass of inner bark, 3.7-11.7% of stem bark biomass, 6.2-9.4% of stem wood production rate and 4.1-5.4% of net production rate of aboveground parts.
The forest vegetation of Kubotani-yama area (Kochi Pref., Shikoku) consisted of six main types, of which three dominated by Tsuga covered 88% of the whole area (471 ha). It was found that 85-87% of number of tall canopy trees in Tsuga forests germinated during a single regeneration period of about 70 years brought about by extensive forest disturbance due to the visit of a big typhoon some 260 years ago. Remaining 13-15% are older trees which survived the typhoon. Seedling regeneration in newer and smaller wind-gaps was also detected, but not very frequent. Pinus densiflora stands were found in a limited area on relatively gentle slopes and presumably originated from old fields of shifting cultivation which prevailed in this district in former times. There was also some evidence of selective logging of Chamaecyparis obtusa trees more than 100 years ago. Otherwise the area remained almost intact, and the wind disaster 2.6 centuries ago played an decisive role in the development of present-day forest vegetation.
Defecation rates, dry weights and numbers of pellets of Sika deer (Cervus nippon) and Japanese serow (Capricornis crispus) were determined at the Sendai Yagiyama Zoological Park for one week each in April, August, October of 1979 and in February or March of 1980. Defecation rates were greater in the Sika deer (11-13 times/day) than in the Japanese serow (2.2-4.6 times/day), while the fecal amounts per defecation were smaller in the deer (c. 19-23 gr, 81-95 pellets/def.) than in the serow (c. 37-64 gr, 200-360 pellets/def.). The daily amounts of defecation were rather greater in the deer (c. 210-280 gr, 880-1200 pellets/day) than in the serow (c. 130-210 gr, 810-980 pellets/day). Slight differences were found in the seasonal changes of the defecation rates and daily fecal amounts for the deer, however for the serow these rate and amount increased in the fall.