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.

北海道石狩市でセグロアシナガバチの営巣事例が確認された．これは北海道における本種の初めての繁殖記録である．

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.