TOGASHI, Katsumi & TAKAHASHI, Fumiki (Entomol. Lab., Coll. Agric., Kyoto Univ.) 1977. Preferential feeding of the last instar larvae of Dendrolimus spectabills BUTLER (Lepidoptera : Lasiocampidae), on the old needles of Pinus thunbergii PARL. in the field. Jap.J.Ecol. 27 : 159-162. In the field as well as in the laboratory, the last instar larvae of the pine moth preferred to feed on one-year-old needles of Japanese black pine, which contribute little to the future growth of the tree. The degree of feeding preference of a larva was closely related to the frequency of larval incidence on the twigs of different age classes. The seasonal change in the degree of feeding preference of large larvae was suggested from their distribution on a pine tree in the field. It was not completely consistent with but similar to that of the last instar larvae obtained from the laboratory experiment.
KIKUCHI, Eisuke (Biol. Inst., Fac. Sci., Tohoku Univ.), FURUSAKA, Choseki (Inst. Agr. Res. Tohoku Univ.) & KURIHARA, Yasushi (Biol. Inst., Fac. Sci., Tohoku Univ.). 1900. Effects of tubificids (Branchiura sowerbyi and Limnodrilus socialis) on the nature of a submerged soil ecosystem. Jap. J. Ecol., 27 : 163-170. Measurements of the chemical and biological nature of submerged paddy soil in vitro with and without tubificids revealed that the presence of tubificids inhibited the growth of weeds and increased the frequency of appearance of Moina sp., and that the presence of weeds led to a increase in the Eh of soil, a decrease in the pH and a decrease in the activity of the soil's biological and nonbiological uptake of O_2. Examination of the changes of biotic and abiotic factors by artificial mixing of the soil led to the supposition that the action of tubificids is similar to physical mixing of the soil.
YUKAWA, Junichi, YAMAUCHI, Seiei, NAGAI, Sadaaki & TOKUHISA, Eiji (Entom. Lab., Fac. Agric., Kagoshima Univ., Kagoshima). 1977. Leaf longevity and the defoliating process in saplings of Actinodaphne longifolia (BLUME) NAKAI. Jap.J.Ecol., 27 : 171-175. This investigation was made as a part of the authors' ecological studies of broad-leaved evergreen trees and associated gall midge populations which have been continued since 1970 in a natural forest of Mt. Shiroyama, situated in the centre of Kagoshima-city. The mean leaf longevity in saplings of Actinodaphne longifolia (BLUME) NAKAI was estimated at 51.58 months by counting both the numbers of surviving leaves and scars of leaves that had been shed. The mean numbers of new leaves per twig fluctuated annualy between 5.13 and 10.60,but the fluctuations were not great in the taller trees or in the younger generations of the shorter trees. The defoliating process from the time of leaf emergence to the end of April in 1976 was indicated by τ-index to be nearly random in almost every year. The simple and easy method adopted in this study may be applicable in some cases for estimating the leaf longevity and the defoliating process of other broad-leaved evergreen trees.
YIM, Yang-Jai (Dep. Biol., Coll. Lib. Arts & Sci., Chungang Univ., Seoul). 1977. Distribution of forest vegetation and climate in the Korean Peninsula. III. Distribution of tree species along the thermal gradient. Jap. J. Ecol., 27 : 177-189. The distribution of 50 woody plant species along the gradient of thermal climate was studied using existing records of their three-dimensional distribution in the Korean Peninsula. The range and frequency of occurrence of the species were examined in relation to KIRA's warmth index (WI). The frequency-WI curves obtained were found to be bell-shaped and more or less symmetrical with a single maximum. The range of thermal distribution of a species was 30-60 (mostly 40-50)℃ month in terms of the WI. The species were grouped into the following 4 groups according to the optimal ranges of their thermal distribution ; subalpine, cool-temperate, warm-temperate deciduous and warm-temperate evergreen group. Unlike other groups, the northern or upward limits of distribution of the species of the last group proved to be most closely correlated with the coldness of winter as expressed by KIRA's coldness index.
HAYASHI Ichiroku (Sugadaira Biol. Lab. of Tokyo Kyoiku Univ.) 1976 Secondary succession of herbaceous communities in Japan. Jap. J. Ecol. 00 : 291-200. In order to explain the alternation of the dominants in secondary sucession, the life histories of the dominant species of each stage in secondary sucession were compared. In the present paper, which is the first of this series, the results of investigation of the seed weight and disseminule form of herbaceous species in relation to succession are reported. Measurements of seed weight of 167 species show that species bearing seed weighing less than 0.1 mg are most frequent. The frequency in number of species decrease rapidly with the increase of seed weight with species bearing seeds over 2.5 mg in weight being very few in number. The dominants in later stages of succession produce heavier seeds than those of earlier stages except in the case of pioneer species, which produce heavy clitochore seeds. The disseminule form of the dominant species in the winter annual stage, perennial herb stage and perennial grass stage is anemochore. A close relationship exists between the disseminule form and the seed weight in each species : anemochore seeds are light while clitochore, bolochore and zoochore seeds are heavy.
TSUKAMOTO, Jiro (Lab. Forest Ecol., Fac. Agr., Kyoto Univ., Kyoto). 1977. Soil macro-animals on a slope in a deciduous broad-leaved forest. I. Two species of terrestrial Isopoda : Ligidium japonicum and L. paulum. Jap. J. Ecol., 00 : 201-206. The forest floors of two plots set up at different locations on a slope, on the ridge and at the bottom, provided different conditions in several aspects, such as moisture, nutrition and physical structure. Two species of Ligidium, terrestrial Isopoda, showed different responses to these differences. Ligidium paulum colonized only the bottom plot, while Ligidium japonicum colonized both the plots on the slope, but the growth rate of the individuals of the species differed between the plots. The individuals from the bottom population grew more rapidly, and finally attained larger body weights than those from the ridge population. The distributions of these species on the slope seemed to be influenced by the difference in the physical structure of the A_0-layer and the top soil between the plots. The difference in the growth rate of the individuals of L. japonicum seemed to be caused mainly by the difference in the moisture conditions and the nutritional conditions of the forest floor.
TODA, Masanori J. (Zool. Inst., Hokkaido Univ., Sapporo). 1900. Vertical microdistribution of Drosophilidae (Diptera) within various forests in Hokkaido. I. Natural broad-leaved forest. Jap. J. Ecol., 00 : 207-214. To examine the spatial aspect of the ecological structure of drosophilid assemblage, its vertical microdistribution within a natural broad-leaved forest was surveyed from the ground up to the canopy. Basically the assemblage was regarded to be composed of two associations, A) floor (herbaceous layer+shrub 1.) and B) canopy ones. Specific components of A were in general herbage or fungus feeders, while B was characterized by tree sap feeders. It was supposed that the sparse subarboreal layer between canopy and floor was less significant for drosophilid life, being mostly used only at migration. This sandwiched structure exactly corresponds to the vegetation structure.
KANAMOTO, Ziyusei (Dep. Fish. Biol., Fac. Agr., Tohoku Univ., Sendai). 1900. On the ecology of hexagrammid fish. III. Niches of Agrammus agrammus (TEMMINCK et SCHLEGEL) and Hexagrammos otakii JORDAN et STARKS and the mode of life of some reef fish. Jap. J. Ecol., 27 : 215-226. The ecology of many species of reef fish has been studied by means of year-round underwater observation around the reef near Benten Island in Sendai Bay, where twenty-one species of reef fish, including two hexagrammid species, coexist. These fish were divided into three major types according to their mode of life (habitat, feeding habits, method of escape and so on), namaly, touching-type, floating-type and swimming-type. The touching-type fish (Agrammus agrammus, Hexagrammos otakii and so on) spend long periods in a solitary state on the rocks or on the algae growing on the rocks. The floating-type fish (Sebastes inermis and others) remain above the rocks or among the algae growing on the rocks, some in a solitary state, and some in a gregarious state in daylight. The swimming-type fish (Ditrema temmincki, Girella punctata etc.) swim on the surface or in the subsurface and bottom layers, mostly in a gregarious state in daylight. Although many species were observed in this particular area, there were few species which compoted with each other.
NAKANO, Kazutaka (Dept. Bot., Fac. Sci., The Univ. Tokyo, Tokyo 113). 1977. A Model for the problem of the effects of defoliation on plant growth. Jap. J. Ecol., 27 : 227-247. The effects of mechanicai defoliation on the accumulation of food reserve in either deciduous trees or deciduous perennial herbs during a semi-long term (one or a few years) were examined with a mathematical model. Its applicability to real cases was satisfactorily confirmed. Analytical consideration through modeling clarified the significance of some plantresponses after defoliation such as the suppression of the growth of non-photosynthetic organs, and resprouting. It suggested that these responses are, in most cases, used to prevent a drastic decrease of the food reserve held by plants. Furthermore, it theoretically reaffirmed the validity of the idea previously advocated by the author on grounds of experimental data that the indicator" Average Leaf Longevity (ALL)" is one of the most fundamental clues to the problem of the effects of defolistion on plant growth. ALL can unify the three factors in the intensity of defoliation pressure, i.e., timing, frequency and severity. Moreover, ALL is almost independent of any response after the defoliation and can be manipulated to represent the outside forces which induce the defoliation. The principle of the model developed here can also be applied to the annuals.