The ecology of two species of Hexagrammid fish was studied by means of underwater observation around the reefs off Benten Island in Sendai Bay throughout the year. Hitherto, it was said that Agrammus agrammus and Hexagrammos otakii coexist in the rocky reef area of the same sea region. Through the course of the present study, however, it was clarified that A. agrammus and H. otakii segregate their microhabitats from each other within a rocky reef area. A. agrammus is apt to stay on the algae growing on the rocks, and H. otakii is often observed on or under the rocks. Furthermore, some members of both species hold definite sites in their own microhabitats for several weeks. The area of the home range varies from 1-14 m^2,and the variation of area may be affected by specific characters and environmental situations. Chasing behavior for area defending was often observed in both species. The two species have similar chasing behaviors, and interspecific chasing was occasionally observed.
Pathological examination and measurements of PCB and organochlorin pesticide residues were made in 18 wild ducks suffering from a disease which took a disastrous toll among waterfowl in the metropolitan area and was thought to be type C botulism. The most conspicous pathological changes observed in these sample ducks were enlargement of the liver, hyperaemia and/or atony in such organs as the small intestine, large intestine and rectum. No such pathological changes were detectable in the ducks caught by shotgun in the suburbs of Abashiri City, Hokkaido, and used as a control. The levels of total BHC, total DDT and PCBs in the sick ducks on a wet tissue basis were within the ranges of trace to 0.190ppm, 0.004 to 0.930ppm and 0.06 to 5.70ppm respectively. These levels were higher than those found in the control ducks. From the toxicological point of view, it can be said that PCB and pesticide residues in the sick ducks were so small that these substances did not participate directly in the cause of the disease.
A method of determing age is proposed for Apodemus speciosus ainu and A. giliacus. In both species 6 relative age classes were created according to wear of the grinding surface of the upper third molar. Based on tooth wear of known-age individuals, pelage color or annual layers on the cementum of molars, approximate chronological age was estimated for each age class as follows : class 1-1 month old, class 2-1 to 2 months old, class 3-2 to 3 months old, class 4-3 to 10 months old and classes 5 and 6-more than 10 months old. The method proposed was compared with those described by previous workers and applied to the trappable populations from different areas of Hokkaido. In both species the current year's mice first appeared in June and made up a large portion of the populations from July.
Polygonum cuspidatum is one of the pioneer perennials in the volcanic desert succession on Mt. Fuji. Energy budget analysis was done to evaluate the effects of environment on plant behavior. Transpiration rate and leaf temperature (i.e. plant behavior) were measured in leaves of a clump and of seedlings of P. cuspidatum together with the parameters of an energy budget equation (the environmental factors) on typical summer days. The data were analyzed by inserting them into the energy budget equation. The transpiration rate-leaf temperature diagram derived from the energy budget equation was able to represent the collective effect of the environmental factors. The diagram showed that the environment of a seedling leaf was much more severe than that of a chump leaf in the sense that both its transpiration rate and leaf temperature were much higher. This severity was caused by high absorbed radiation and air temperature. Since a seedling grows solitarily and close to the heated, bare soil surface, its absorbed radiation and air temperature were considerably higher than those of a clump leaf under insolation. The screen climate in this region does not indicate such severity. To evaluate actual plant behavior, therefore, it will be necessary to consider the plant's microclimate.
Smaller individuals showed larger relative growth rates in both laboratory and field conditions. The relation between the rate of O_2 consumption (r : μl/ind. hr) and live body weight (w : mg) was formulated as r=0.260w^<0.768>. The relation of daily food consumption (f : mg in dry weight) to live body weight was approximated as f=0.058w^<0.760>. Based on the annual mean population density, the annual mean body weight and O_2 consumption-body weight regression, the annual respiratory energy loss of whole cockroach populations was estimated at 5.35 kcal/m^2.