KAWAKATSU, Masaharu (Biol. Lab., Fuji Women's Coll., Sapporo) Report on the ecological survey of freshwater planarians in the Hidaka district, Hokkaido. Jap. J. Ecol. 15,173-183 (1965). In this paper, the vertical distribution of freshwater planarians in the Hidaka district in South Hokkaido is reported. Most of the district is covered with mountains. The Hidaka Mountains, the backbone of South Hokkaido, are situated in Lat. 41°50′N. to 43°10′N. and Long. 142°30′E. to 143°20′E., the highest peak, Mt. Poroshiri-dake (2052 m above sea level), is at the northern corner of the mountain-chain. Topographical evidence of the Pleistocene glaciation has been found on the summits of the mountains. The area consists largely of plutonic and metamorphic rocks. The southern part of the Hidaka Mountains consists of two topographical units, one is the lower mountainous land (the main peak, Mt. Apoi, is 810 m high) and the other is the flatsurfaced hilly land (the Erimo Cape district). The Hidaka district has a rigorous climate. The average temperature of the year is about 6° to 7℃ and the rainfall amounts to about 1000mm at the foot of the mountains or at the seashore districts (cf. Table 1). Surveys were made on the rivers, creeks, brooks, brooklets and springs of the mountain and seashore districts in August of 1958,1961 and 1962. In the area surveyed in the Hidaka district, six species of freshwater planarians, Phagocata vivida (IJIMA et KABURAKI), Phagocata tenella ICHIKAWA et KAWATATSU, Polycelis sapporo (IJIMA et KABURAKI), Polycelis auriculata IJIMA et KABURAKI, Polycelis akkeshi ICHIKAWA et KAWAKATSU and Dendrocoelopsis lacteus ICHIKAWA et OKUGAWA, were found. In the Hidaka district, two other species of planarians, Dugesia japonica ICHIKAWA et KAWAKATSU and Dendrocoelopsis ezensis ICHIKAWA et OKUGAWA, were collected by Prof. A. ICHIKAWA and Dr. T. KAWAI. D. japonica is one of the most common freshwater planarians in the Japanese Islands. In the Hidaka district, however, this species was collected only in the brooks flowing through the seashore district (Hidaka-Mitsuishi) and the plain (Obihiro City and Otofuke River). Ph. vivida was rather common in the creeks, brooks and brooklets within the altitude range from the level of the seashore to about 1200 metres above. Ph. tenella, which may be a subterranean inhabitant, was found only in the pools of swampy land and in the spring-fed brooklets in the Mt. Apoi district. This species was found in the stations below the altitude of about 580 metres. Pol. auriculata was common in the creeks, brooks, brooklets and springs in the altitude range from about 90 to 1700 metres or more. Pol. sapporo was found everywhere in the rivers, creeks, brooks and brooklets both in the seashore district and the stations below the altitude of about 800 metres. Pol. akkeshi was found only in the brooklets in the Mt. Apoi district. Den. lacteus was found only in the brooklets in the Mt. Apoi district (st. 54 and st. 55). Den. ezensis was collected only in the brooklets in Obihiro City. The inhabitable water temperature ranges of the above mentioned species of freshwater planarians which were found in the Hidaka district are as follows : Ph. vivida (5.8〜11.8℃) ; Ph. tenella (12.1〜20.9℃) ; Pol. auriculata (10.5〜13.5℃) ; Pol. sapporo (6.8〜20.9℃) ; Pol. akkeshi (12.8〜20.9℃?) ; Den. lacteus (17.8〜18.2℃). Two or three of the above mentioned species were found together where their inhabitable water temperature overlapped. The type of vertical distribution in the Hidaka district is JSV-SVA-VA-A (J : D. japonica ; V : Ph. vivida ; A : Pol. auriculata ; S : Pol. sapporo).
OKUNO, Ryonosuke (Suma Aquarium of Kobe City, Kobe). Foods and behaviors of the rocky reef fishes on the coast of Asamushi, Mutsu Bay. Jap. J. Ecol. 15,183-188 (1965). During Sept. 1964,the behaviors and food relationships of fishes were investigated on the rocky coast of Asamushi, Matsu Bay. Twenty-five species were observed by underwater diving and 62 specimens belonging to 16 species were collected. The dominant species of this region were the following ten species : Girella punctata, Mylio macrocephalus, Opisthocentrus zonope, Pholis ornatus, Ditrema temmincki, Fugu niphobles, Sebastes inermis, Agrammus agrammus, Hexagrammos otakii, Pseudoblennius cottoides. Six among these ten species were also found along the rocky coast of Kasaoka Bay, Seto Inland Sea, by FUSE (1962). Food animals of these fishes were concentrated to the phytal animals, especially Gammaridae. Similar concentration had been found also on the rocky reefs of Kasaoka Bay in Autumn (FUSE, 1962). From these facts, it may be said that the fish communities of the rocky reefs of Asamushi and kasaoka fundamentally coincide with one another.
SASABA, Takafumi (Kyoto Univ., Kyoto) Interspecific competition between two species of Trichogrammatidae. 2nd report. How are the competition outcomes influenced by the difference of host's distribution. Jap. J. Ecol. 15,189-193 (1965). There are two different views in the study on the interspecific competition between the species which have similar ecological needs. One of these is the analysis of the mechanism involved in the many different processes of competition during the whole life (BAKKER 1961,etc.), while another is emphasizing the final result of competition mainly from the mathematical treatment (NEYMAN et al. 1955,etc.) In the previous report the author stated the importance of the analysing research for progressing the study on the interspecific competition using two species of parasites (Trichogramma japonicum ASHMEAD and T. minutum RILEY)(SASABA 1964). In this paper an attempt is made to discuss on the same problem based upon another experimental result, comparing with those of the previous report. Although, in the previous report the host (eggs of Cadra cautella WALKER) was distributed in the containers (container A : 8cm in diameter, 3.5cm in height, and 126cm^3 in volume ; container B : 19cm in diameter, 5cm in height, and 2550 cm^3 in volume). In this experiment the host is distributed in a mass within an area of 3cm in diameter at the center of the container B. The ratio of number of wasps to the number of hosts at the start of the experiment varied with changing of the number of wasps (Experiment I) and the number of hosts (Experiment II). Though the outcome of competition is not simple, a clear tendency in the result is observed as had been observed in the previous report. T. minutum in this experiment had more opportunities to remain as a population than in the experiment of the previous report. Considering with the previous report in the present study, the low density of wasps, the wide area of rearing space, large number of hosts, and clumped distribution of the host take advantage of the outcome of T. minutum. While the result is vice versa under the reverse conditions. It can be said that the competition for the host finding in the adult wasp is the main factor under the former condition, and on the other hand the competition for food in the larval stage of the wasp is main one under the latter condition. The difference of ecological characters between the two species of parasitic wasps plays an important role on the competition processes and outcome, but the competition processes are varied with the different enviromental conditions. Thus, for clarifying the complex mechanism or competition, it is important to find the difference in the ecological characters between the two species. It is necessary to discuss the problem from the analytical standpoint of the process of competition rather than from the mathematical treatment of outcome in competition.
UTIDA, Syunro (Entom. Lab. Kyoto U., Kyoto) "Phase" dimorphism observed in the laboratory population of the cowpea weevil, callosobruchus maculatus, IV. The mechanism of induction of the flight form. Jap. J. Ecol. 15,193-199 (1965). In the population of the southern cowpea weevil, Callosobruchus maculatus, the existence of two distinctly different forms was observed by the writer (UTIDA, 1954) and CASWELL (1956). One is very active in its behavior and can fly while the other which is of rather dark body color can not fly. Distinction between both forms is not only morphological but also physiological and behavioristic (UTIDA 1956 ; Utida & TAKAHASHI 1958 ; CASWELL, 1960). It was observed that the active one appears when the density of the weevil population is high (UTIDA 1954). Therefore, the experiments were made to prove the soundness of this observation. It was found that with the increase of the percentage of emergence of the flight form increases in both sexes the density of the larval population in a bean from 1 to 6 (Fig. 1). The temperature in a small heap of beans (20 gr. or 40 gr.) rises to 6° to 8° above the air temperature of the environment (30℃), when the larval density in a bean is so high as to produce the flight form in high percentage (Fig. 2). This seems to be a mechanism due to the density effect, thus determining the emergence of the flight form. This condition was proved by the simple experiment that the high percentage of emergence of the flight form is seen even in the uncrowded population, when the rearing temperature rises from 30° to 36° at a certain stage of larval life. The stage most susceptible to high temperature is the third instar. The following course is assumed for the operation of the density effect : crowding of larvae of the older stage→heating of the heap of bean→induction of rather young larvae to flight form.
HANEDA, Kenzo and Mitsuhiro KOIZUMI (Shinshu Univ. Nagano) Life history or the Black-Eared kite (Milus migrans lineatus) I. Breeding season Jap. J. Bcol. 15,199-215 (1965). This report deals with nest building, copulation, egg laving, incubation, hatching, chick raising, fledging, family stage, roost, share of male and female in breeding season, territory and productive relations of life in during the breeding season of the Black-eared Kite, based on the results of the outdoor observations for the purpose of studying the life history of the birds in the Zenkoji basin (altitude 350-360m) in the northern part of Nagano Prefecture from November 1962 to January 1965. The main part of the observations was done in the Koshoku district in the southern part of the basin, and most of the life history during the breeding season of the bird was described based upon the observation of one nest in 1964.