Geographic information systems (GIS) were adopted in order to determine the population density of rats in residential areas in Ota-ku, Tokyo. The GIS data was converted into a building occupancy index and a building number index, and compared with the rat population data based on interviews with inhabitants in three investigation districts. Three indices in three investigation districts (800 m×400 m) were analyzed in every compartment (50 m×50 m). The results suggested that the population index of rats corresponded with the number of trapped rats and rat signs. The population index of rats was positively correlated with increasing building coverage and/or the number of houses and buildings. Therefore, GIS can facilitate forecasting the rat distribution.

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Habits of the sow bug, Porcellio scaber LATREILLE, that is, their termite shelter preference, daily behavior, aggregation effect of excreta, and breeding period, were observed under laboratory conditions and in field investigations in Sapporo. Sow bugs preferred termite shelters most and did not select rotten timber. No traces of gnawing were found on naturally deteriorating fir timber. Under laboratory conditions (in the petri-dish with humidified vermiculite), sow bugs were nocturnal, prowling around at night. The males and the females might be found aggregated perfectly in association with feces only of the same sex. Based on a field study, the breeding period of sow bugs was presumed to be from June to September.

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Arena experiments were conducted in June 2006 to investigate the daily activity of new adults of the red flour beetle, Tribolium castaneum Herbst. The beetles exhibited nocturnal activity and left the harborage shelter to reach the food tray or to forage around on the floor as well as on the shelter every night, though they gradually tended to stay near the food area. More beetles leaving the shelter were seen in the southern area of the arena floor that was lighter than the northern area. Normal food traps caught as many beetles as traps preoccupied by four beetles each. Adults were observed to move from the center of a vacant room to 12 food traps placed alongside the surrounding walls within two days in June, July, and August. About 30% of the released adults were captured in the traps in two days when the room temperature on the floor ranged between 26 and 33℃ in the experiments of June and August, although only 7% were captured when the temperature was between 22 and 27℃ in July. Greater numbers of captured adults tended to be seen in the traps on the lighter side of the room. These results indicate that red flour beetles are nocturnal and begin to move to the lighter side before searching for food or foraging.

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Food preference in susceptible or field-collected German cockroaches was studied one week after they were released in an arena containing four kinds of powdered food materials. Rice bran, mouse food, wheat flour and dog food were placed in small plastic cups positioned at regular intervals. The consumption rate was then checked. All test cockroaches preferred dog food most, followed by wheat flour in field-collected colonies. Though mouse foods are commonly used in laboratory rearing, mouse food consumption rates in all tested colonies were lowest among all food materials. Dog food is thus recommended for laboratory bait or field-collecting lures.

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[in Japanese]

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