The biological economy in the nymph of Locusta migratoria when it feeds on the leaves of the grass Bromus unioloides was studied with special reference to dry matter and phosphorus at a constant temperature of 25℃. The phosphorus contents of the food plant, nymphal body, feces and the exuviae were 0.35%, 0.93%, 0.22% and 0.03%, respectively. The conversion efficiency for dry matter from the plant to the insect body was 16%, while that for phosphorus was 52% ; the latter being thus about three times as much as the former.
The forest communities of the warm temperate zone in Kiyosumi region of the Boso Peninsula, were classified by the numerical method. Similarity between the plots was calculated from the data of the cover percentage and floristic composition of trees and climbers of the high tree layer. Three measurements of similarity, the angular coefficient, the standardized Euclidian distance and the coefficient of Jaccard, and one clustering technique (WPGMA) were practiced. Then three different dendrograms were obtained. As the different measurements of similarity produce different systems of classification, the synthesized technique treating these results was sought and practiced. The groups of plots which always belong to the same clusters in the three different dendrograms were designated as the vegetational "core". Each core was regarded as the unit of vegetation. Four forest types were found by considering the size and floristic composition of the cores, and finally 89 plots were classified into 14 forest units.
In Honshu, P. fascipes is univoltine in the north but bivoltine in the south, and there is a transitional area where the two life cycles coexist. A univoltine strain produced diapause eggs even in long days (>14 hr) and its nymphal growth showed a short-day type response. Strains from the transitional area averted diapause in long days, and the critical photoperiod was longer in the north than in the south. They were dimorphic in nymphal development : the fast-growing fraction took the longest time to mature in intermediate days (14 hr), but the slow-growing fraction was delayed by long days. The two fractions thus corresponded to the univoltine and bivoltine cycles, respectively. Hybrids between the univoltine and dimorphic strains developed at an intermediate rate between the parents. Despite this, they would be able to cope with the seasonal changes by the feedback effect of the photoperiodic response on the nymphal development. Therefore, any disruptive selection would not occur.
Observations were made on bud break, shoot elongation, leaf development and defoliation of alder (Alnus hirsuta TURCZ.) in a deciduous hardwood forest stand in Hokkaido. Leaf emergence started in early May. The mean number of leaves attached to a shoot increased progressively until late June or early July when it reached a maximum, about 5 leaves a shoot, and then decreased to zero in early November. Leaf defoliation increased during late June and July, and again after September. Mean longevities of leaves were 90 and 97 days. The mean longevities of the first and the second leaves were shorter than the other leaves. The first, the second and the third leaves were classified as early leaves from the morphological features. These three leaves were assumed to be different functionally also from the other leaves.
Formica (Formica) yessensis FOREL has a supercolonial system. Each worker can visit any conspecific nests without receiving hostility. Although this system suggests irregular roaming of workers in the field, the present study clarifies that many, if not all, workers are fairly conservative to particular tasks or working areas for a certain period.
The effects of oxygen deficit on the photosynthetic and respiratory activities of submerged plants were investigated from eco-physiological viewpoints. It was found that a long period of oxygen deficit extending over 24 hours didn't cause irreversible decline of net photosynthesis and respiration. Specific differences in the tolerating ability to the lack of oxygen were recognized. These might be accounted for by the differences in the oxygen economy of each species. The possibilities that dissolved oxygen condition affects the lives of submerged plants are discussed.
The formation of floating islands in Lake Rawa Pening originated from the population growth of Eichhornia crassipes. The floating islands dominated by E. crassipes are replaced by Panicum repens and Eriocaulon cinereum in an advanced stage of succession, and Leersia hexandra and Eragrostis amabilis were the dominant species in the final stage of succession on the islands. The soils in several seral stands and silt at the bottom of lake contained many viable seeds. The numbers of seeds and species in 490 cm^3 soil were 45 grains and 19 species in Eichhornia-Sacciolepis stand, 75 grains and 15 species in Panicum-Eriocaulon stand and 60 grains and 7 species in Leersia-Eragrostis stand. The soil at the bottom of the lake also contained considerable numbers of seeds. The floristic composition of the islands differs from that of the buried seeds most of which belong to Cyperaceae. The seeds of E. crassipes were found in the stands in later stages of succession, whereas the species declined in its dominancy of the standing vegetation.
Simultaneous observations of the accumulation of soil organic carbon, the rate of litterfall and soil respiration were made periodically over a period of one year in a preserved cool-temperate beech/fir forest on Mt. Odaigahara, Nara Prefecture, central Japan. Based on a simple compartment model of the dynamics of soil carbon, it was shown that the carbon cycling in the soil was considerably slower in this forest than that in the driest stand of warm-temperate evergreen oak forest, owing to lower temperature and probably to the perhumid condition of soil throughout the year. The seasonal variation of the dynamics was also analyzed by the same model to show comparatively high decomposition rates of soil organic carbon in mid-summer, lower rates in other parts of growing season, and the interruption of decomposition under snow cover during winter months.
Picea glehnii forest was found by ISHIZUKA (1961) on Mt. Hayachine located in the central Iwate Prefecture as the southernmost one in Japan, as far as we know. The tree species composition and their natural-regeneration in this forest were investigated in the fall of 1976. The Picea glehnii trees are distributed in the mixed conifer forest and partially grow on serpentine rock adjacent to the Aion-zawa ravine. This forest is composed of several conifers such as Picea glehnii, Pinus parviflora var. pentaphylla, Tsuga diversifolia, Thujopsis dolabrata var. hondae and a few deciduous broad leaved trees. Picea glehnii is a dominant in this community above-mentioned. Judging from results obtained in connection with the natural-regenerated seedling being found around Picea glehnii stumps and on the bare ground, the authors can describe that these seedlings will grow up to the new young forest stand in future. It is not so clear why Picea glehnii has still survived in this area far from the center of its distribution, however the main cause for such a phenomenon primarily depends upon the fact that Picea glehnii community is apt to grow on a serpentine zone, and Picea glehnii has generally a long life.
The study is aimed to stress the importance of littoral region in the lake for the two gobioid fishes (Tridentiger obscurus and Rhinogobius giurinus) from the view point of biological production. Seasonal changes in density and mean body weight were estimated by monthly sampling. Both species showed seasonal migrations in the lake ; in spring they immigrated from offshore to littoral region for spawning and feeding, while in winter they emigrated for overwintering from littoral region to offshore. Production rates of both fishes were estimated by ALLEN's method in each of the littoral region and offshore, and the significance of littoral region for production of both species was discussed in relation to their seasonal migrations.