Tick cell lines are invaluable tools for research on ticks and tick-borne pathogens. The range of their applications is constantly being expanded. Tick cell lines have some common characteristics, some of which are different from insect and vertebrate cell lines. In this review, the characteristics of tick cell lines and their applications to studies of ticks and tick-borne pathogens are introduced.

In the past decades, omics data including genomes, transcriptomes and proteomes of several tick species of medical and veterinary importance have become available as web-based resources. In addition, laboratory colonies and tick cell lines have been established and are now essential tools for the advancement of tick research. Unfortunately, currently, such databases and the biobank of the ticks distributed in Japan are insufficient. To date, available data are from Haemaphysalis longicornis Neumann, 1901, one of major hard tick species in Japan and a vector of various microorganisms that are harmful to human and animals. H. longicornis has been used as an “experimental model of hard tick” for biological and physiological studies and for validation of effectiveness of insecticides or acaricides in research institutions. The parthenogenetic tick is used as research material because it can be stably supplied. This mini-review provides a concise overview of recent advances of omics approaches in tick research. The importance of laboratory colonies of ticks and the prospect of tick research in Japan are also discussed.

Tick saliva exhibits several biological functions such as adhesion, cytolysis, vasodilation/vasoconstriction, angiogenesis, anti-platelet aggregation, anti-blood coagulation, anti-complement activity, anti-inflammatory, and immunosuppressive activity, and so on. The saliva is secreted by salivary gland, and the injected saliva facilitates blood uptake during the tick bite. Tick-borne pathogens are transmitted to vertebrate hosts via the saliva. This means that the tick saliva plays a key role in the pathogen transmission. In this session, we would like to introduce the ‘Immune-modulatory factors including immunosuppressant’ in the tick saliva.

We evaluated an insecticide-impregnated net, originally invented for malaria vector control, as a tool to control vectors and stored product insects in a laboratory trial. First, we performed the standard continuous contact test on German cockroach, American cockroach, house fly, cigarette beetle, rice weevil, and red flour beetle; lethal effects were found on all of these insects, except red flour beetle. The house fly and cigarette beetle were affected very rapidly in the contact tests. Second, we disclosed that seating the net proved to act as a barrier against American cockroach. From the third day of the experiment, the roaches did not enter the shelter in the treated zone, and the quantity of feces left on the control shelters was greater than that on the treated shelters. Thus, the net was shown to repel the roaches from the treated shelters. Third, suspending a strip of the net in a cage had knockdown and lethal effect on house flies and flesh flies. This study has shown the applicability and the utility of an insecticide-impregnated net to control pests other than malaria vectors.

There are few reports of chironomid fauna in Kamikochi because it is located in a special protection zone in a national park. The objective of this study is to clarify the species composition of chironomid midges, using a sweeping net and a light trap in Kamikochi, Taisho-ike Pond Area, Tashiro-ike Pond Area, Kappa Bridge Area and Miyojin-ike Pond Area. In addition, previous records are reviewed in accordance with the objective of this study. An abundance of chironomid midges were collected using a sweeping net late in May of 2010, and late July and September in 2011. We also collected chironomid midges using a light trap in the Miyojin-ike Pond Area late in May of 2010. We collected 901 adults representing 68 species of chironomid midges (6 species of Chironominae, 57 species of Orthocladiinae, 2 species of Diamesinae, 1 species of Prodiamesinae and 2 species of Tanypodinae) in 4 Kamikochi areas during the investigation periods. Limnophyes was the dominant genus (14 species), followed by Micropsectra (6 species), and Stictochironomus akizukii (Tokunaga, 1940), Limnophyyess pentaplastus (Kieffer, 1921) and Corynoneura sp. were the common species in Kamikochi. A total of 40 genera, 92 species of chironomid midges in Kamikochi, Chubusangaku National Park, Japan are described.

The attractiveness of frog sounds to biting Uranotaenia mosquitoes and Corethrella midges was determined using natural and synthesized sounds. The traps with each species’ call of eight frog species or a series of them, were set in a forest of Iriomote Island. Out of 17 mosquito species collected, Uranotaenia macfarlanei Edwards was the predominant species. Most Ur. macfarlanei females were collected by characteristic calls which had dominant frequency of about 1,000 Hz. We synthesized 23 sounds which varied in frequency spectrum (original burst, sinusoidal, and noise), wave form, repeated rhythm, and loudness of sounds. The burst sound was synthesized by editing the original scream of male Fejervarya sakishimensis Matsui et al., which had two dominant frequencies of 1,038 Hz and 2,312 Hz. The sinusoidal sound had a dominant frequency of 1,000 Hz, while the noise sound had no dominant frequency. Uranotaenia macfarlanei females were collected with the original burst and sinusoidal sounds more than noise sound. They were also well attracted when loudness was higher than about 75 dB SPL. The original burst sound also attracted Corethrella nippon Miyagi more than sinusoidal and noise sounds. Prediction model indicated that low loudness sounds still attracted C. nippon compared to Ur. macfarlanei.

The red imported fire ant, Solenopsis invicta Buren, was first recorded from Japan during 2017. Since then, the Biodiversity Center, Ehime Prefectural Institute of Public Health and Environmental Science (BCEJ) has received a total of 70 reports about ants suspected to represent this species from the citizens of Ehime Prefecture. In addition, BCEJ conducted monitoring surveys for the ants at four ports of entry (Mishima-kawanoe Port, Matsuyama Port, Niihama Port, and Imabari Port) in Ehime Prefecture on 10 July 2017. Samples obtained during these surveys and submitted by citizens were identified to genera and evaluated for their status as non native invasive species by staff at BCEJ, and the results were delivered immediately to concerned individuals at the sources. Subsequently, samples were further identified to 21 species within 14 genera and four subfamilies by the first author. Results include seven exotic species, S. geminata (Fabricius), Monomorium chinense Santschi, M. pharaonis (Linnaeus), Trichomyrmex destructor (Jerdon), Pheidole indica Mayr, Tetramorium bicarinatum (Nylander), and Tapinoma melanocephalum (Fabricius), new distributional records for Shikoku for T. destructor (Jerdon), and new records for Ehime Prefecture for M. pharaonis (Linnaeus) and Lasius meridionalis (Bondroit). In addition to ants, 14 out of 70 reports referred to Myrmarachne elongata Szombathy, which is a salticid spider that mimics and superficially resembles ants.

A record of Schizocarpus sp. (Acari: Chirodiscidae), obtained from a captive American beaver (Castor Canadensis) residing at a Japanese aquarium, is provided with measurements. This is the first record of the genus Schizocarpus mite genus in Japan.