1. Behaviour patterns of a green frog, Rana nigromaculate, were observed at two small pools on the campus of the Kyushu University, from July to September, 1955. Individuals were marked by clipping their toes off, and also by tying colored vinyl strings to their bodies. 2. It was observed that most of the individuals stayed at the pool area for a long period. In the daytime, they rested in the shallow pits burrowed by themselves in the poolside, but at night, they left these pits for foraging. The home range of an individual was restricted to a small portion of the waterside of the pool. Early in the morning, the individuals returned to the sites near the resting places of the previous day, and some of them were observed to occupy the same pits of the previous day (Fig. 2). 3. In many cases, the home ranges of the individuals overlapped each other, but no aggressive or other repulsive behaviors were observed. Therefore, it may be said that this species does not hold territory at least in the non-breeding season. 4. The resting sites of an individual were not distributed at random around a pool, though it was a small one. Instead, it was observed that each individual had its own favorite place for resting (Fig.3 and Table 2). Once an individual settled in a place, it stayed there for several days, keeping its home range nearby. Then it moved to a new place which was usually not far from the first place. Such movings were observed repeatedly in the pool area. 5. Twenty new individuals were introduced experimentally into the smaller of the two pools. The daily changes of components of the inhabitants in each pool after this treatment are shown in Fig. 4. This figure seems to suggest that the dispersion of the individuals during the rain was accerelated by the high density due to the artificial transplantation, though it had been inhibited by the drought continued for several days at the beginning of the experiment.
1) ONDO and MORI reporded the outline of the periodic journey of the shore isopod population in 1956. The present paper deals with some results of my further investigations executed at the natural habitat. 2) The isopod population migrates periodically twice a day as mentioned previously. From investigations executed at the natural habitat, it was concluded that there was no direct interrelations between the periodic journeys and changes of tidal level. They always go towards the beach early in the morning and reach the feeding places on the intertidal rock surfaces. They repeat the following characteristic behavior, i.e. when the tide rises, they retire to the high part of drift line but do not return to the resting places, on the contrary, when the tide lowers, they again return towards the drift line. Thus, the range of feeding and migration was limited by the changes of drift line in the daytime, as shown in Fig. 1. In the late afternoon, they commense their evening journey to return to their resting places just before sunset. Thus, it was ascertained that the periodic journey of the isopod population is influenced by periodicity of environmental factors as daily changes of solar illumination, but on the other hand, it was also true that the internal physiological conditions (chiefly diurnal changes in conditions of alternative hunger and satiety)and interspecific relationships are also important. From the ecological point of view, the periodic journey of the isopod population belongs to the recurrent movement. 3) An attempt was made to learn something of the nature of the physiological conditions in the detailed forms of the daily cycles of the melanophores and of the daily changes in conditions of alternative hunger and satiety. The melanophores were staged at hour intervals through 24 hours. The average stage of melanophore was determined by estimating the average melanophore state on the dorsal surface of the walking leg, antennae and dorsal surface of the body. The classification based upon HEWER's study was used, with 1…contracted, 2…slightly stellate, 3…stellate, 4…slightly expanded, 5…expanded, 6…fully expanded. A detailed analysis of the character of the diurnal changes in the melanophores of M. exotia confirmed the precision of the 24 hour endogenous rhythm as indicated in Fig. 2. On the other hand, to see clearly the changes in conditions of alternative hunger and satiety, 20-30 individuals of the same agers-as-semblage(individuals of 20-30mm body length)were collected at hour intervals through 24 hours at the natural habitat and afterwards, dissected to confirm whether their conditions of alternative hunger and satiety. Generally, all members of the agers-assemblage just mentioned taking morning journey were in conditions of hunger and those of evening journey were sufficiently fed. Therefore, the state of such internal physiological conditions affect the time when the isopod population begins to take morning and evening journeys. From these experiments, it is pointed out that the time when all members of the isopod population begin to take morning and evening journeys was synchronized with the changes in conditions of alternative hunger and satiety. These facts are indicated in Fig. 2. 4) When migrating, all members of the same population run from rock to rock. To investigate the behavior patterns, some experimental analyses were carried out under natural conditions. As a result, it may be concluded that the isopods seek an adequate pathway to the feeding or resting places with their thigmotactic sense. These results are shown in Table 1.
The investigation on the epiphytic bryophyte community on Cornus controversa HEMSL in Shiia cuspidata forest, Mt. Kamimata Kochi Prefecture, Shikoku, is reported. The epiphytic bryophyte community on Shiia cuspidata MAKINO in the present forest has already been reported(1957,159-162). The flora, vertical distribution and growth form of the epiphytic species on Cornus controversa HEMSL are showed Table 1. There were found 11 species of Musci and 30 of Hepaticae on the trunks of the sample trees. Dominat species on the trunks of the sample trees. Dominat species on the part of trunk base (0-1 m. in height) are Plagiochila japonica and Neckera yezoana, on the trunk (2-7 m. in height)aare Forrostroemia trichomitra and Brachiolejeunea sandvicensis, on both parts of the crown base and crown (8m in height) are Frullania truncatifolia. As above mentioned the species on the bark of Cornus controversa and the dominant species on Shiia cusupidata are shown Table 2. Common species on both tree-trunks are Brachiolejeunea sandvicensis and Frullania truncatifolia. In the preceding study, the writer reported six distributional types by the vertical range and the value of frequency on the treetrunks. These vertical distribution-types and the typical species of each types on Shiia cuspidata MAKINO and Cornus controversa HEMSL are shown in Table 3. The common species of vertical distributiontypes on both tree-trunks are Plagiochila japonica(Type A), Pycnolejeunea obutusilobula(Type C) and Brachiolejeunea sandvicensis (Type E). The ratio of species number of growth form on different levels of sample trees are shown Table 4. The chief growth form is the Hardly pressed mat type(Hp)in the present epiphytic community.
In the previous report the authors concluded that swimming away of rice nematodes from the seed is related to the temperature and the budding of the seed soaked in the water. The present paper deals with the fluctuation of survival percentage of swimming nematodes, their ability of injuring the rice plant and the movement from injured hill to normal hill in the seedling stage. Most of these studies were conducted using the experiment pot in the sun shine and the difference of plant growth and the stems injured by the said swimmings were surveyed in each growing stage of the plant. But the population in the unhulled rice was observed under a binocular microscope within about one month after the harvest. The results obtained are as follows; 1. The survival percentage of swimming nematodes was related to the period of time after swimming away from the seed soaked in the water and the longer the time becames, the lower was the survival percentage in each experiment temperature of 20-25℃, 25℃ and 30℃. It is supposed that some higher survivals in the seed-bed may occur because the temperature in natural seed-bed is lower than in this experiment. 2. The number of injured stems tends to decrease somewhat with the elapse of days from swimming away till its parasitic time, although it was not distinguished within four days. This tendendy which was observed on the population in unhulled rice seemed to be rather clear. 3. It was considered that swimming nematodes did not attack the young root of the seedling, according to the results of the test in which only the root was dipped into the water in which a large population of the swimmings were contained. Therefore, it was supposed that the swimming nematodes attacked the other parts of the seedling except the root. 4. When injured seedlings and normal ones were mix-planted, injury in normal seedlings was recognized in the same degree as the injured ones, therefore it was considered that the swimmings moved actively from hills to hills. Moreover the movement between hills was related with the nitrogenous manure and in the twice-N fertilized group its movement reached to the maximum at the 1st leaf-stage of the seedlings, although in the normal group at the 3rd-4th leaf-stages.
The algae and the aquatic insects in the riffle and pool of Satsuki-gawa, Tsukigase-mura of Nara Prefecture were ecologically studied from the first to third of August in 1956. (1) As a result of comparing and discussing the algal communities of 4 points in a riffle (Fig. 1 )where current velocities were different, it was found that, as they changed from a point of large current velocity to that of small one, the structures of the communities changed as follows. Cyanophyceae community→Cyanophyceae and Diatomaceae community→Chlorophyceae and Diatomaceae community (Table 1,2). The quadrate of 50cm×50cm was set in the riffle and algae and aquatic insects were quantitatively collected. As the result, the dry weight of the sample excluding the aquatic insects was 10.93g, the ash and mineral substance weighed 6.58g and the ignition loss, 4.35g. The constitution of the algal community in this quadrate had a strong resemblance to that of the point C where the current velocity was almost equal(Table 1,2). (2) At a pool of about two metres deep(Fig. 2)an experiment was made to find the relation between the light intensity and the production by the photosynthesis of algae according to the difference of the depth. At the same time, the algal communities at some points of different depth were studied. The result is as follows. In the pool above mentioned the production by assimilation reduced considerably as the depth increased ; but the constitution of the benthic algal community in different depth remained almost the same. Consequently, the light as the environmental factor is considered not to have enough influence to change the components of algal community in this degree of the difference of depth(Tables 1,2,3). Besides, the structures of algal communities of the points E, F, G of the pool(Table 2)resembled to that of the point A of riffle where the current velocity was very small. (3) The floating matters were collected quantitatively by a plankton net in the riffles and pools, and the dry weight of the sample, the weight of ignition residue and that of ignition loss were measured. The ignition residue represents almost the abioseston, the ignition loss represents almost the bioseston.(We wish to name the matter carried by the current potamoseston). Also, the percentage constitution of each species of algae in the flowing matter samples was examined (H, I, J in Table 2). Ecological meanings of the flowing matters were discussed from the results of the above studies. (4) Rich insect fauna (Table 5) was found in the riffle, the standing crop being caluculated as 40 gr/m^2. On the contrary the insect community in the pool was very poor, its standing crop was only 0.081 gr/m^2.