Seasonal and spatial distributions of blowflies in relation to reproduction were investigated by baited traps in eight sites from lowland to high mountainous areas in Hokkaido, Japan. A total of 6,571 blowflies consisting of seven species in three genera was collected. The most predominant species was Calliphora vomitoria (Linnaeus) (5,946 flies, 90.5%), followed by C. nigribarbis Vollenhoven (537 flies, 8.2%). The remaining five species (Triceratopyga calliphoroides Rohdendorf, C. vicina Robineau-Desvoidy, C. loewi Enderlein, C. subalpina (Ringdahl), and Aldrichina grahami (Aldrich) were few in numbers. Calliphora vomitoria had the highest peak in autumn (October) in lowland to upland areas (70 m, 400 m, and 500 m), and it was also abundant from July to September in highlands (1,000–1,150 m). Calliphora nigribarbis was present in low numbers, but it was comparatively abundant in summer in highland areas (1,000–1,150 m). Emergence traps yielded 1,441 individuals from four species (C. vomitoria, C. nigribarbis, C. vicina, and T. calliphoroides), showing their reproductive potential in each site. Of these, C. vomitoria and C. nigribarbis emerged at 500 m (Nissho Pass) and 1,850 m (Mt. Kurodake) in August, indicating that they have reproductive cycles at upland to high mountainous areas. Further, adult emergence of C. vomitoria in 2009 from traps placed in the preceding autumn at Mt. Kurodake showed that this species can hibernate at high altitudes. For C. vomitoria, 62.7–84.1% of females had matured follicles (stages IV–V), and mating rates were very high (99.5–100%) in lowland and uplands in October. At Mt. Kurodake, high percentages of females of C. vomitoria and C. nigribarbis had mature follicles from July to October, with high mating rates. Life histories and reproduction of blowflies in Hokkaido were discussed.

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Since Culex inatomii was rediscovered in Kansai International Airport, Osaka, Japan in 1998, a few additional habitats of this mosquito have been found in central and eastern Japan. We examined the results of the nationwide mosquito surveillance conducted recently by Japanese Quarantine Stations and the occurrence of Cx. inatomii was confirmed at the following 6 ports and 2 airports; Port of Wakkanai in Hokkaido Prefecture, Port of Ishinomaki and Port of Sendai-Shiogama in Miyagi Prefecture, Port of Fushiki-Toyama in Toyama Prefecture, Port of Osaka in Osaka Prefecture, Port of Kobe in Hyogo Prefecture, Niigata Airport in Niigata Prefecture, and Kansai International Airport, Osaka. In spite of the intensive mosquito surveillance at Port of Otaru, Niigata, Nagoya and Hiroshima, no Cx. inatomii was collected. The seasonal prevalence of Cx. inatomii larva and adult is summarized with the associated mosquito species.

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The Tsunami caused by the Great East Japan Earthquake on 11 March 2011 in north-eastern Japan destroyed urban and rural environments completely, including buildings, dwellings, roads, bridges, agricultural fields and natural vegetation. The after-effects of the Tsunami on the distribution and abundance of mosquitoes were studied in rice field areas in Miyagi Prefecture, Japan during June to August 2011. Adult mosquitoes were collected by traps enhanced with 1 kg dry ice and the density was compared between the “Tsunani” area and “No Tsunami” area. A total of 6,542 adults of 9 species in 4 genera were collected and the following 4 species were dominant: Culex pipiens pallens,Cx. inatomii,Cx. tritaeniorhynchus and Aedes albopictus. The high density and expanded distribution of Cx. inatomii was marked. The adult density of the former 3 dominant species was significantly higher in the Tsunami area than No Tsunami area, while Ae. albopictus was significantly abundant in the No Tsunami area. Ground pools in disaster areas contained brackish water with 0.47 and 0.21% average salinity in June and August 2011, respectively. The percentage of water samples with mosquito larvae increased from 2.7% in June to 79.5% in August, suggesting the expansion of the larval distribution of Cx. inatomii and Cx. tritaeniorhynchus as well as Anopheles sinensis-group.

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To evaluate vector situations in the disaster areas of the Great East Japan Earthquake we conducted field studies on the occurrence of mosquitoes in Rikuzentakata City, Iwate Prefecture and Kesennuma City, Miyagi Prefecture almost every three weeks from June to October and in Minamisoma City, Fukushima Pefecture in September 2011.
For adult collections we placed dry-ice baited CDC-light traps at selected sites and captured totals of 3,088 Culex pipiens, 1,430 Cx. tritaeniorhynchus, 62 Aedes albopictus, 58 Cx. inatomii, 13 Anopheles sinensis, and 8 Ae. togoi. The first two species were captured in large quantities. Mean adult density of Cx. pipiens pallens, Cx. tritaeniorhynchus and Cx. inatomii at Tsunami sub-area was significantly higher than No Tsunami and boundary sub-area. In each study area, many larval habitats such as unmanaged paddy fields, destroyed houses, and ground pools were found with brackish water. We collected immature of An. sinensis, Cx. tritaeniorhynchus and Cx. inatomii from those larval habitats. Larvae of Cx. pipiens pallens were abundant in wells, fish tanks, irrigation channels and roadside gutters remained in the area. Also, many larvae of Ae.togoi were collected at a high rate from exposed septic tanks at the basement of destroyed houses and broken fishing boats.

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We surveyed the occurrence of rats in Miyagi Prefecture, a Tsunami disaster region of east Japan, in early November 2011, eight months after the Tsunami event. Snap-traps were set for 210 trap-nights in four sites, which were seemingly filled with diet, but no traces of rats were observed. Also we found no sign of rats in areas surrounding the trapping sites including temporal fish markets. However, nest holes, runways and fresh footprints of the Norway rat, Rattus norvegicus, were identified in an outside corner of a rice storehouse at a port. We conclude the Tsunami swept away most of the rats.

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The Great East Japan Earthquake was a magnitude 9.0 (M_w) that occurred on March 11, 2011. The earthquake triggered extremely destructive Tsunami waves of up to 38.9 meters (128 ft) in height that struck almost all architecture and fields in the disaster areas, in some cases traveling up to 10 km (6 mi) inland.
Areas affected by the Tsunami were estimated approximately 400 km² in Tohoku District, located from latitude 35° to 43°. Almost all architecture in the affected area was carried away to the inland or also into the sea. A lot of debris was scattered in the harbor, inland resident area, and field areas.
In this summer we focused on occurrence of mosquitoes, such as Aedes togoi, Ae. albopictus,Culex pipiens group,Cx. tritaeniorhynchus, and Cx. inatomii in the disaster areas hit by Tsunami. After cleaning up the big debris from residential area, a lot of septic chambers and tanks related to sewage disposal system remained open. Almost all tanks contained water with salt concentration 0–3.0%. We mainly found and collected Cx. pipiens group, Cx. inatomii, Ae. togoi, Ae. japonicus, Ae. albopictus, Ae. vexans nipponii, Ar. subalbatus from the artificial water containers such as septic chamber and different type of artificial containers. Unfortunately local governmental offices practically did not have any time to concentrate to control mosquitoes, so mass production of several mosquito species occurred in the area. Local governments should be concerned about the big outbreak of mosquitoes in the next spring or early summer and have to plan and construct the mosquito control strategy until next spring.

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After the Great East Japan Earthquake fly abundance was investigated in the tsunami-devastated area in Ishinomaki, Miyagi Prefecture from early June. The fly infestation level was evaluated by the number of flies captured on sticky sheets (30 cm×30 cm) installed on inside and outside walls of evacuation facilities. The mean outside fly density during 8 to 17 June was 35 flies/sheet/day, and increased to 128 flies during 24 to 30 June. The fly density increased continuously until mid-July when the investigation was relocated to another facility. The maximum fly density was 248 flies/sheet/day during 13 to 19 July. The population density dropped steeply in the end of July and did not increase until mid-October. Species composition of the Family Muscidae exceeded 90% inside the facility from early June to the middle of July. The Family Muscidae also predominated outside, but the composition of the Family Calliphoridae reached 50% in total during 13 to 19 July. Several reasons for the fly reduction were proposed, but the cause remained unclear. Ecological studies on fly population will be required in 2012 to clarify factors determining fly density in the tsunami-devastated areas.

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The Great East Japan Earthquake brought unprecedented damages caused by great Tsunami which was unexpected by even experts of disaster. In the field of medical entomology, uncountable number of flies emerged from putrid fishes, brown rice and organic fertilizer which were spread from destroyed storehouses on the shoreline. A number of mosquito larvae were observed at newly appeared standing water bodies, a lot of destroyed septic chambers and tanks related to sewage disposal system at tsunami-stricken areas. The members of Department of Medical Entomology, National Institute of Infectious Diseases visited Miyagi and Iwate Prefectures of Tohoku Tsunami-stricken regions for 11 times in 2011 to survey the medically important pest insects. Here, we report, with pictures, the situation of these nuisance and vector insects which explosively emerged at Tohoku eastern seashores.

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Multitude frozen fish were strewed around the Tsunami disaster areas from huge freezing storehouses in the northern Japan on March 11, 2011. There were outbreaks of blow flies from rotten fish in the following months. We carefully worked out on the control strategy after investigating rotten fish in the early May from Tanohata-town, Iwate Prefecture, the northernmost study city, to Kesennuma-city, Miyagi Prefecture, the southernmost study city. The larvae of Calliphora nigribarbis were abundant in the early May in the rotten fish, and a few of the adults were found around houses at that time. From the end of May to June, the adults of this species were stormed to the residents. Then, Phormia regina and other blow flies were replaced to C. nigribarbis. The pest control operators from all over Japan were requested to spraying heap of rubble and rotten fish from May to September in the Tsunami disaster areas. We selected Etofenprox emulsion according to the efficacy and avian low toxicity as insecticides and Fenitrothion EC as for the rest. Fly population declined in the end of July by the insecticide spraying, replacement of gavages rubble-mountains or dried-up rotten fish. The high susceptibility of the blow flies to the insecticide was found.

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We surveyed the flies in the tsunami disaster region after 2011 the Great East Japan Earthquake. Mass occurrence of flies were observed there, which mainly consist of Calliphora nigribarbis in early spring, Phormia regina in spring-summer and Musca domestica in summer. Of these, P. regina was the most abundant species, and emerged from dead fishes dispersed from destroyed marine product processing factories.

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