I investigated the distribution of nest holes of Norway rats in the planting zone along sidewalks of the Showa Street that passes through Taito-Ku and Chiyoda-Ku, Tokyo. The holes disappeared in three survey sites among four in the Taito-Ku area from the year 2016 to 2018. Also, they disappeared in six sites among eight in the Chiyoda-Ku area from the year 2013 to 2018. Possible causes of the disappearance include physical blockage of planting zones by asphalt cover, waste reduction projects by local governments, and renewal of buildings to larger ones. The urban renewal reduces roadside stores, which serve food source for rats by putting garbage in plastic bags on roadside.

There have been few reports on mosquito fauna in Karuizawa Town. The objective of this study was to clarify the species composition of mosquito fauna, using 3 CDC traps and 3 Ovitraps, and collecting mosquito larvae near these traps in Karuizawa Town, the Seishoji Temple and the Nagakura residential area. I collected 95 individual mosquitos representing 3 genera and 6 species during the investigation periods. Culex pipiens complex was the dominant group in Karuizawa Town.

A nest of Polistes jokahamae Radoszkowski (Hymenoptera: Vespidae) was found in Ishikari City, Hokkaido, Japan. This is the first breeding record of this species in the Hokkaido Prefecture.

The presence of Supella longipalpa in Hokkaido has been reported for the third time. An apparently established colony was found in a restaurant in Yubari City. The cockroaches were found primarily in warm and low-humidity areas of the restaurant kitchen. A total of 83 individuals were collected during survey and pest control activities, including adult males, adult females and nymphs; 24 oothecae were also collected. The cockroaches were apparently reproducing at the collection site.

Quick instar judgement factors without using head-width measurement are described for the smokybrown cockroach, Periplaneta fuliginosa. Body color and pattern are useful for younger instar judgement. Pronotum width can be used as a stable factor to revise unstable body size judgement. The white or pale part of the antennae can also be used.

The habitat range of the native widow spider, Latrodectus elegans Thorell, is limited to the Yaeyama Islands (Okinawa Prefecture) in Japan, and its sharp population decline may be due to pesticides exposures and changes in the agricultural landscape. In our survey, a single female of L. elegans and its 6 egg cases were collected on Hateruma-jima Island for the first time since 2001. Unfortunately, the invasive brown widow spider, L. geometricus Koch (8 females and 42 egg cases), which is declared a noxious species in the Invasive Alien Species Act of Japan, was simultaneously collected for the first time from this island. Competitive exclusion of L. elegans by L. geometricus is a concern because they share a similar niche. Therefore, it is essential to carefully monitor the population dynamics of these two widow spiders for the conservation of L. elegans.

The homing instinct of Vespa analis was observed on a breeding nest in 2017. Several workers marked with white paint were released from different points. Individuals released from distances of 320, 640, and 1000 m were confirmed on the nest surface, but the homing instinct from 1700 m was not confirmed.