When adults of mixed sexes were confined in a small cage (17cm×17cm×14cm height) containing 6 smaller plastic test containers (3cm diameter, 5cm height) each of which had a small hole of 6mm diameter at the center of the sealing cap, most femeles (94.7-100%) entered the containers through the holes. Most femeles (89.4-93.3%) selected test containers with larval food (rice bran) if available, deposited their eggs, and died in the containers, producing many larvae in the food.
However, most femeles (84.6-92.9%) entered test containers even when no larval food was contained in all the containers in the cage. This suggests that mated femeles would search for and enter smaller spaces to hide, to find out larval food and deposit their eggs. Males in the mixed populations sometimes tended to enter test containers but sometimes not, suggesting that they would respond rather to other factors such as virgin females than to the containers or larval food.
When only virgin femeles were confined in the cage without males, more individuals (36.4-60.0%) died outside test containers, suggesting some behavior such as calling outside males. When only unmated males were confined without females, more individuals (77.8-92.2%) entered and died in test containers, also suggesting some behavior such as searching for females.
Both males and females could pass through smaller holes of 3mm diameter, although females clearly preferred holes of 6mm diameter when the two sizes of holes were available.
When adults of mixed sexes were confined in a larger cage (57cm×57cm×30cm height) nearly half of females (48%) entered test containers, and most of them (92%) selected test containers with larval food, suggesting that mated females sought the larval food. While most of the males (80%) died without entering the containers, and the rest of them entered the containers with larval food.
Unlike in the small cage, very few females (as well as very few males) entered test containers when no larval food was contained in all the containers in the large cage. This and the results in the small cage suggest that even female adults do not directly respond to and pass through the tiny openings, but they had to respond to and land on the shadowy area, or to food odor before finding tiny holes or crevices and getting into them.

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To examine the susceptibility of the wild house mice (Mus musculus L.) to warfarin, a no-choice feeding test with 0.025% warfarin bait was carried out using the house mice caught in Japan. Furthermore, the same test as mentioned above was conducted using ICR strain mice and roof rats, Rattus rattus.
As a whole, 84 mice were tested for fixed periods ranging between 3 and 38 days. All mice excluding two died within two weeks. The lowest fatal dosage was 86.3mg/kg in 3 days by a female from Sagamihara and the highest fatal dosage was 1,396.0mg/kg by a male from Chiba. Over 97.6% of all mice which examind this time showed high susceptibilities to the warfarin.
We found that both introduced subspecies, M. musculus castaneus from Chiba harbors and M. musculus domesticus from Ogasawara island, showed a tendency of higher values of lethal dosages and days than of M. musculus musculus from Funabashi and other inland areas. On the other hand, F₁ and F₂, which were descendant between ICR mice and survivors eaten 0.025% warfarin bait during 12 days, did not show any resistance to 0.025% warfarin bait.
House mice fed 0.025% warfarin bait of 2 times as much as that of roof rats, Rattus rattus on the first day in the feeding test for certain days and the lethal dose in the former were 1.69-3.04 times as much as that of the latter, which showed the susceptibility for 0.025% warfarin bait.
Two house mice from Chiba harbors and Ogasawara island reduced consumption of the poisonous bait two to five days during the test, which was supposed to cause delay of time to death.

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Behavior of the German cockroach, Blattella germanica, in a vinyl tube in imagination of a drainpipe was observed in the laboratory. The cockroaches were released in the plastic container (17×28×18cm) and kept for a few days for acclimation. After acclimating, the plastic container was connected to the end of a vinyl tube (20m in length, 3.5cm in diameter) placed on the floor in the laboratory. New harborages installing a refuse (7×9×5; made of white cardboard) were connected to the vinyl tube at the distance of 3, 5, 10, 15, 20m from the plastic container. When the food and water placed only in the plastic container, the cockroaches did not enter the harborage at a distance of 20m from the plastic container. Although a few cockroaches entered the other harborages, they did not stay there. On the other hand, when the food and water were placed in each harborage, many cockroaches especially females entered the harborage at a distance of 20m from the plastic container. Once cockroach entered the harborage, they seemed to stay in the same place.

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We investigated seasonal changes in the age composition of the roof rats, Rattus rattus, in an urban building in Yokohama. Age was determined from eye-lens weight of the rats caught with glue traps every month from January to December 1996. Of 242 rats (with a maximum of 33 rats in March and a minmum of 8 rats in April) trapped during the year, 23.2% (with a maximum of 40.0% in December and a minumum of 4.4% in January) were 30 days old or less. Theses resuits showed that they breeded all the year round, although there were slight seasonal changes in the activity.

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Field trials of Methoprene, slow release formulation Altosid^R 10F, Pyriproxyfen, bubbling tablet formulation Sumilarv^R, and Bacillus thuringiensis var. israelensis, VectoBac^R 12AS, against chironomid midges, Chironomus kiiensis and Polypedilum nubifer, were carried out at secondary sewage effluent water tanks in the Kurobe Municipal Sewage Treatment Plant.

At a rate of 0.83ppm A.I. of methoprene, 100% prohibition of emergence was recorded during 2 months after treatment. At a rate of 0.09ppm A.I. of Pyriproxyfen and 0.48ppm A.I. of B.t.i., the emergence was prohibited completely during 1 month post-treatment.

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[in Japanese]

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[in Japanese]

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