HAYASHI, Fumio (Dept. Biol., Fac. Sci., Tokyo Metropolitan Univ., Tokyo). 1985. Factors affecting the handling time of the dobsonfly larva, Protohermes grandis (Megaloptera, Corydalidae). Jap. J. Ecol., 35 : 1-11. Handling time, that is the time from biting a prey item with mandibles until completely swallowing it, of the dobsonfly larva Protohermes grandis, a predatory aquatic insect dwelling in the mountain stream, was measured under the laboratory conditions. It increased exponentially with the prey size. Size relation between the labium width of the dobsonfly larva and the body width of prey was important to determine the handling time. Water temperature affected the handling time (Q_<10>=3.8), but the degree of hunger did not affect it. The kind of prey was another important factor affecting the handling time which was changed by the difference in shape and hardness of prey. In addition, prey profitability was estimated based on the handling time/dry matter gain. There was the most profitable prey size for the dobsonfly larva, at which the time required to eat 1 mg dry weight of prey was minimized. This most profitable prey size was independent of water temperature, but changed by the difference of prey kinds.
KATO, Jun (Dept. Biol., Fac. Sci., Osaka City Univ., Osaka). 1985. Food and hoarding behavior of Japanese squirrels. Jap. J. Ecol., 35 : 13-20. The food habits of Japanese squirrels were studied in a pine-deciduous mixed forest for four years. Out of a total of 699 sightings, 698 (99.9%) were of plant matter. One sighting of animal matter was the corpse of a squirrel. Among the species of plants consumed, 22 (16 trees, four vines and two grasses) were identified. The main food was walnut cores, Japanese red pine seeds and larch seeds, which composed 68.1% of the total sightings. Various portions of plants (seeds, nuts, fruits, buds, leaves, flowers, bark and sap) were utilized in different seasons. Some food was hoarded in tree folks and under the ground as scattered hoarding, a behavior which was observed mainly in autumn. Walnuts and pine cones were hoarded both arboreally and underground, but mushrooms were only arboreally hoarded. Since underground hoarded food was eaten mainly in the next spring, walnut hoarding in autumn was suggested to be important in the winter and spring life of the squirrels.
SUZUKI, Nobuhiko (Dept. Biol., Fac. Sci., Kyushu Univ., Fukuoka), NIIZUMA, Akio (Dept. Zool., Fac. Sci., Kyoto Univ., Kyoto), YAMASHITA, Keiko (Lab. Ent., Fac. Agric., Kyoto Prefec. Univ., Kyoto), WATANABE, Mamoru (Dept. Biol., Fac. Educ., Mie Univ., Mie), NOZATO, Kazuo (Lab. Ent., Fac. Agric., Kochi Univ., Kochi), ISHIDA, Akiyoshi (Tosa High School, Kochi), KIRITANI, Keizi (Div. Ent., Nat. Inst. Agro-Environ. Sci., Ibaraki) and MIYAI, Shun'ichi (Div. Inform. Anal., Nat. Inst. Agro-Environ. Sci., Ibaraki). 1985. Studies on ecology and behavior of Japanese black swallowtail butterflies. 2. Daily activity patterns and thermoregulation in summer generations of Papilio helenus nicconicolens BUTLER and P. protenor demetrius CRAMER (Lepidoptera : Papilionidae). Jap. J. Ecol., 35 : 21-30. Daily rhythms of flying activity and habitat selection in relation to thermoregulation were investigated in Kochi City, Shikoku, Japan, for the summer generations of Papilio helenus nicconicolens and P. protenor demetrius. Since the body temperature rose with the increase of ambient air temperature, cooling was considered to be more important than heating for thermoregulation in the summer. Both species normally flew inside the forest and seldom flew out from it in the daytime. Males seldom encountered females in the daytime, because most females roosted inside the closed forest. In the evening, the butterflies left the forest for a prolonged flight in the open area. Resources for feeding and oviposition were mainly restricted to the gaps and the forest margin, so that P. helenus, which was more sensitive to ambient air temperature than P. protenor, concentrated on feeding and oviposition activities in the evening. Females of P. protenor mainly flew for feeding and/or oviposition in the gaps in the afternoon. This resulted in high flight and chasing activities of males in the afternoon in P. protenor and in the evening in P. helenus. Activity patterns in relation to thermoregulation strongly affected the resource utilization patterns and mating systems of the butterflies.
MARUYAMA, Naoki (Fac. Agric., Tokyo Noko Univ.). 1985. Kidney and marrow fats as indices of fat reserves of Japanese serows. Jap. J. Ecol. 35 : 31-35. Analyses of 525 Japanese serows (Capricornis crispus) from Gifu and Nagano Prefectures in two winters of 1979-1980 and 1980-1981 revealed that the kidney fat index was useful for estimating a wide range of body fat contents, but inadequate for estimating to lower levels, which are most accurately revealed by measurement of both femur marrow fat and tibia marrow fat. Expression of bone marrow dry weight as a percentage of its fresh weight was found to be a more convenient and accurate method than chemical methods such as the Soxhlet extraction method.
TSUKAMOTO, Jiro (For. Exp. Sta. Kochi Pref., Kochi). 1985. Soil macro-animals on a slope in a deciduous broad-leaved forest II. Earthworms of Lumbricidae and Megascolecidae. Jap. J. Ecol., 35 : 37-48. Species richness of earthworms on the studied slope was comparable to that in the best mull soils of Europe, in spite of the strong acidity. Species number did not differ substantially between the ridge part with "mor-type" humus and the bottom part with "mull-type" humus. Biomass of earthworms was larger at the bottom than on the ridge, reflecting the better conditions at the bottom. The difference in earthworm biomass in the studied site was smaller than that in the mull and mor soils of Europe. This difference seemed to be related to differences in the amount of precipitation and in the background for differential development of mull and mor soils in the two places. Vertical distribution of earthworms as a whole clearly differed between the ridge and bottom of the slope. This difference seemed to be affected by the presence of absence of the F (H)-layer and by the difference in soil depth originated from the difference in the mode of sedimentation of the parent material of the soil between the two parts of the slope. Individual earthworm species had respective habitat preference in soil profile. This preference also seemed to be affected by the factors mentioned above.
TAKEUCHI, Jun-ichi & HATA, Yoshihiko (Fac. Agr., Kochi Univ., Kochi). 1985. Distribution of bacteria associated with various sizes of particulate matter in Harima-nada and Hiuchi-nada areas, Seto Inland Sea, Japan. Jap. J. Ecol., 35 : 49-56. The size-distribution patterns of bacteria associated with suspended, sinking and sedimented particles were investigated in coastal waters. Seawater, newly-formed deposits and bottom mud samples were collected from Harima-nada area, which is highly polluted with industrial wastes, and Hiuchi-nada area, which is contaminated with effluent from a pulp mill. The collected samples were then sizefractionated with nylon mesh nets and Nuclepore filters to elucidate the relationship between the size of particulate matter and the number of associated bacteria. In the seawater collected from Harima-nada area, 50-90% of aerobic heterotrophic bacteria were free-living, while 70-90% of those in the newly-formed deposits or the bottom mud from the same area were attached to the particles, of which particles having 10-50 μm diameter were most abundant in the bacteria. In a polluted site of Harima-nada area, nearly half of the bacterial isolates from both the newly-formed deposits and the bottom seawater were denitrifying bacteria. In a pulp-contaminated site of Hiuchi-nada area, a great number of cellulolytic bacteria were found ; however, none of them could be detected in a free-living state in the bottom mud samples.
YONEDA, Tsuyoshi (Lab. Environ. Sci., Fac. Educ., Osaka Kyoiku Univ., Osaka). 1985. Relation of wood diameter to the rates of dry weight loss and CO_2 evolution of wood litter in evergreen oak forests (Studies on the rate of decay of wood litter on the forest floor, V). Jap. J. Ecol., 35 : 57-66. In his previous papers, the author discussed the leading role of bulk density of wood litter in determining the in situ decomposition rate on the forest floor. Field experiments in the evergreen oak forest of warm-temperate Japan showed that the wood diameter was also an important factor. The effect of mean bulk density (ρ^^-) on mean relative rate of dry weight decrease (r^^-) for different diameter (d) classes could be approximated by the equation, r^^-=-α'd^^-^<-0.2>ρ^^-+β. The same relation was found also for the rate of CO_2 evolution from wood litter. The coefficient β is the maximum relative rate of decomposition at d^^-→0,i.e. very fine wood or at ρ^^-→0,i.e. the final stage of decay, where the dry weight of litter is expected to decrease exponentially. The time course of weight decrease was also formulated to reveal the relation of wood diameter to the decomposition curve.
SAITO, Hideki & TAKEOKA, Masaji (Dept. For., Fac. Agr., Kyoto Pref. Univ., Kyoto). 1985. Pollen production rates in a young Japanese red pine forest. Jap. J. Ecol., 35 : 67-76. Annual pollen production rates were studied in a 35-year-old forest of Japanese red pine (Pinus densiflora) near Kyoto, Japan. Male flowers sampled just before the anthers opened contained 3.17 mg of pollen, corresponding to 60% of dry weight of male flowers with pollen, and 2.45×10^5 pollen grains. There was no difference between the pollen amounts in unproductive and productive years for male flowers. From the dry weight or number of pollen per male flower and the annual fall rates of make flowers per hectare, which were measured with litter traps, annual pollen production rates during the years 1979-1983 were found to range from 55 kg ha^<-1>y^<-1> to 96 kg ha^<-1>y^<-1> (mean ; 79 kg ha^<-1>y^<-1>), and from 4.4×10^<12> no. ha^<-1>y^<-1> to 7.6×10^<12> no. ha^<-1>y^<-1> (mean ; 6.2×10^<12> no. ha^<-1>y^<-1>). The ratio of the maximum to minimum annual production rates was 1.8,which was one-eighth of the ratio of Chamaecyparis plantations studied by us. The maximum production rate in the study forest was estimated to be 100 kg ha^<-1>y^<-1> in dry weight and 8×10^<12> no. ha^<-1>y^<-1> in number, corresponding to 50% and 22% of that of Chamaecyparis plantations, respectively.
INOUE, Ken (Bot. Gard., Fac. Sci., Univ. Tokyo, Tokyo). 1985. Reproductive biology of two Platantherans (Orchidaceae) in the island of Hachijo. Jap. J. Ecol., 35 : 77-83. Capsule sets of Platanthera okuboi (abbreviated as okuboi) and P. mandarinorum ssp. hachijoensis (hachijoensis) on Hachijo Isl. and factors affecting them were investigated. Average percentages of capsule set of hachijoensis at two study sites were both over 90%, while those of okuboi were much lower and 20-30%. From patterns of capsule formation and the number of trapped pollinaria-bearing moths, okuboi was estimated to be pollinator-limited, and hachijoensis unlimited. In okuboi, the decrease of pollination and increase of predation were observed in a closed habitat, and larger spikes were more effectively pollinated than smaller ones. In hachijoensis, nearly all the flowers were pollinated regardless of habitats and spike size, and the level of predation was low and unchanged in different habitats. It was pointed out that the two Platantherans are under different evolutionary dynamics.
NAKANISHI, Hiroki. (477-53,Ohte-machi, Nagasaki City). 1985. Geobotanical and ecological studies on three semi-mangrove plants in Japan. Jap. J. Ecol., 35 : 85-92. The three semi-mangrove plants ; Myoporum bontioides, Hibiscus hamabo and Paliurus ramosissimus were studied-geobotanically and ecologically. Distribution maps showing both the locality and size of communities dominated by the three species respectively were drawn. These species grow luxuriantly throughout the northernmost part of their distribution areas. The structure of disseminules and tests of buoyancy and viability in salt water proved that these species could disperse by sea currents. The species compositions and habitats of these communities were described. The Myoporum bontioides community is described as the new association Myoporetum bontioidetis which is usually monospecific. The association Hibiscetum is composed of only Hibiscus hamabo in the shrub layer and occasionally with some halophytes in the herb layer. The Paliurus ramosissimus community is invaded by many non-halophilous herbs. These semi-mangrove communities occur far more widely than the distribution areas of mangrove.
OKUNO, Ryonosuke (Dept. Biol., Fac. Sci., Kanazawa Univ., Ishikawa). 1985. Studies on the natural history of the Japanese toad, Bufo japonicus japonicus. V. Post-metamorphic survival and longevity. Jap. J. Ecol., 35 : 93-101. Post-metamorphic survival rates of the Japanese toad, Bufo japonicus japonicus, inhabiting the Botanical Gardens of Kanazawa University were as follows : Survival rate between 1 and 2 years of age was about 40% ; between 2 and 3 years of age was 40-70% ; between 4 and 5 years of age was 65-80%. Survival rates were decreased gradually after age 5,although they were kept over 50% to age 8. Four out of 178 individuals, which had been marked at age 1 in the autumn of 1973,were still surviving in the spring of 1981 (9 years old). Longevity of the males was presumed to be 11 years, and that of the females was estimated at 8 or 9 years. Sex ratio (♂/♀) of matured toads was 2.71.
OHNO, Masahiko (Tokyo Metr. Res. Lab. Pbl. Hlth., Tokyo). 1985. Ecological studies on chironomids in Tokyo. III. Tolerance of two species of chironomid larvae collected from the Zempukuji River to oxygen deficiency. Jap. J. Ecol., 35 : 103-111. Tolerance to low dissolved oxygen contents was examined in two species of chironomid larvae collected from different regions of the Zempukuji River. Chironomus yoshimatsui, which was dominant in the upper region (characterized by weak water flow and severe oxygen deficiency at night), was tolerant of low oxygen content. On the other hand, Cricotopus bicinctus, which was generally dominant in the lower region (characterized by faster water flow and less severe oxygen deficiency), was sensitive to the low content of oxygen. Rarity of Cr. bicinctus in the upper region may be explained by its sensitivity to the low oxygen content. Oxygen consumption of the chironomid larvae was measured at various concentrations of dissolved oxygen in water. It seemed that hyperbolic relations existed between the oxygen consumption rates of the chironomids and the oxygen concentrations. Reduction of oxygen consumption rates accompanied by lowering of oxygen concentration was not significantly different between the two chironomids per individual weight, but the more tolerant Ch. yoshimatsui showed less reduction per unit body weight.
OKITSU Susumu (Dept. Biosystem Management, Div. Env. Conservation, Grad. School of Env. Sci., Hokkaido Univ., Sapporo). 1985. Consideration on vegetational zonation based on the establishment process of a Pinus pumila zone in Hokkaido, northern Japan. Jap. J. Ecool., 35 : 113-121. The characteristic features and process of establishment of the Pinus pumila zone in Japanese high mountains were explained, and their ecological significance was discussed in relation to that of the vegetational zones, including both vertical and horizontal ones. The P. pumila zone is a unique vegetational zone which is not an extension of the forest zone regarded as the timberline ecotone, nor is it dependent on the Kira's Warmth Index 15. The P. pumila community invades into high mountain areas, which are forest areas under thermal conditions but become deforested by strong winds and heavy snows in winter, and finally, extends into the areas and forms the P. pumila zone there. The horizontal counterpart of this zone is the Larix dahurica forest zone in eastern Siberia, and P. pumila is presumed to have been a remnant element of L. dahurica forest in the Last Ice Age, and to have established its own vertical zone in high mountain areas of Japan after the last Ice Age.
ENDO, Akio and OIKAWA, Takehisa (Inst. of Biol. Sci., Univ. of Tsukuba, Ibaraki). 1985. Effects of winter coldness on photosynthesis and transpiration of Quercus myrsinaefolia seedlings grown under different light levels. Jap. J. Ecol., 35 : 123-131. As the first step in the analysis of forest succession in the northern district of the Kanto plain, the characteristics of photosynthesis and transpiration of Quercus myrsinaefolia Blume (a kind of evergreen oaks) were investigated in winter using seedlings grown under the following four levels of light transmissibilities : 100%, 45%, 15% and 5%. Some light adaptive responses were clearly observed in the light-photosynthesis curve for the seedlings grown under relatively shaded conditions, especially under the 5% plot. The net photosynthesis rate at the equivalent light intensity, however, was lower under shaded conditions (5% and 15%) than under bright conditions (45% and 100%). The seedlings in all plots suffered from winter coldness which reduced the light-saturated maximum photosynthesis rate, but under the most shaded growth condition (5%), the reduction was postponed and its degree was minimized. These were regarded as a protection effect of the shading. Such an effect is expected on a forest floor under a dense canopy.