Approximately 50 years have passed since the author first used mosquitoes as experimental material for his undergraduate thesis. During this period, there were many instances when research on mosquitoes was interrupted. However, the author did not give up his research on mosquitoes, even when he was conducting research on other experimental materials, such as protozoa. The main mosquitoes studied were the so-called “yabuka” in Japanese, such as Aedes albopictus (Skuse). These mosquitoes were used to study their biology; susceptibility to novel insecticides; and susceptibility to arboviruses, such as dengue, West Nile, chikungunya, and Zika viruses, and conduct a transcriptome analysis of dengue virus infection using next-generation sequencing (NGS). To continue his research career, he moved through four universities in Japan. During that time, he acquired for arboviruses, for vaccine development of protozoa, and for epidemiological studies on vector insects, using molecular biological tools. New techniques and research ideas in these different fields have been of great help to the author when resuming mosquito research in Japan. This paper summarizes the viral susceptibility and vector competence of mosquitoes and the research that has led to them.

Larvae of Scenopinus fenestralis (Diptera: Scenopinidae) were collected from nest sediments of the White-throated Needletail Hirundapus caudacutus (Apodiformes: Apodidae) in Hokkaido, Japan. This is the first instance of Scenopinus fenestralis recorded from Hokkaido. Furthermore, S. fenestralis was recorded for the first time from the nests of Apodiformes.

An analytical method for pyriproxyfen in water, sediment and fallen leaves was developed, and then occurrence of pyriproxyfen in street gully in Tokyo was investigated. Glass was found to be suitable as material for sampling containers, and pyriproxyfen was most adsorbed onto the polypropylene container. The established analytical method was simple and accurate enough to detect pyriproxyfen as low as 1/300 of its recommended concentration. The concentrations of pyriproxyfen in almost all of the water samples were lower than the recommended concentration, whereas relatively higher concentrations of pyriproxyfen were found in the sediment samples. These results suggest that pyriproxyfen may be accumulated in the sediment in street gully. Results of laboratory experiments for pyriproxyfen degradation in water and sediment suggest that pyriproxyfen in water was gradually degraded by microorganisms in the water in street gully. For the sediment in street gully, pyriproxyfen was degraded gradually under flooded aerobic conditions, while it was little degraded under non-flooded aerobic conditions.

Sixteen species of mosquitoes across eight genera were identified from the Noto Peninsula, Honshu, Japan, using the CO₂ trap method, between 2009–2020. Culex tritaeniorhynchus was collected from all 12 surveyed areas but had distinctly less abundance in the cow house area at the top of the hill; it was more abundant in the relatively large paddy field area. Culex tritaeniorhynchus tended to be captured more in traps placed inside paddy fields than those placed outside paddy fields.

In this study, we report the following Blattodea species: 1) Balta vilis from Izena Island; 2) Lobopterella dimidiatipes from Kudaka Island; 3) Blattella lituricollis from Aguni Island; 4) Periplaneta australasiae from Tonaki Island, Okinawa Islands, 5) Episymploce sundaica sundaica and P. australasiae from Kitadaito Island, Daito Islands, 6) E. sundaica sundaica and Py. indicus from Tarama Island; 7) Py. indicus from Shimoji Island, 8) Py. indicus from Kuroshima Island; 9) Py. indicus from Yufu Island; 10) E. sundaica sundaica from Kohama Island, Yaeyama Islands.

The prevalence of bed bug (Cimex lectularius) infestations has increased worldwide, and the development of resistance to insecticides has emerged as a major obstacle in effectively managing these pests. This study assessed the efficacy of Vectron™ FL, a novel pesticide containing broflanilide as its active ingredient, in reducing bed bug infestations in real-life environments. Between October 2021 and December 2023, treatments were administered to 30 infested accommodations spread throughout 12 prefectures in Japan. Bed bug presence was evaluated using interviews, visual inspections, and traps, whereas treatment effectiveness was established by post-treatment inspections and the absence of complaints. All 30 instances of bed bug infestations were effectively managed within four treatment sessions, with no instances of inefficacy or complaints after treatment. Our research indicates that Vectron™ FL, with its innovative method of operation, is a highly efficient tool for preventing and managing bed bug infestations in housing situations. Additional investigation is required to evaluate the long-term effectiveness and capacity to hinder the formation of bed insect populations, particularly the tropical bed bug.