イエバエの経産に伴う卵巣小管の形態的変化による年令推定法と野外個体群への応用

The present author established the table of diagrammatic calendar ages of the housefly females, Musca domestica vicina, applicable to each month of the breeding season. The table was made on the basis of the examinations for the development of follicles and ovariole changes following oviposition carried out under various laboratory conditions. Using the table for the determination of age distribution of female populations collected in nature at intervals before and after the application of different residual insecticides to the different three villages, and comparing the changes in age distribution of the female populations collected in each village, he tried to evaluate the effect of the insecticides used.著者はイエバエMusca domestica vicinaを25℃,約70%比湿の下で1対飼育し,年令既知の雌群について濾胞の発育,経産に伴う黄体の濾胞管基部(現濾胞から小輸卵管までの間の部分)における分布,量,及び色彩等を調べて,本種の年令を未経産,1回,2回及び多経産に区分した(第1表)3回以上の多経産雌の場合にはこれを更に区分することは出来ないが,25℃,70%比湿の下で飼育したものでは11回も産卵をくり返す雌がある.継続1対飼育した雌群についてみると,卵塊当りの卵粒数は最初から5回位迄は大体100粒程であるが,経産が進むにつれてわずかずつ減少する.しかしこれらの雌群の死亡率をみると第6回産卵以後は極めて急激にその率が高くなる.第1回目のgonotrophic cycle(=前産卵期間)は25℃で7日を要するが,第2回目以後(=産卵間隔)は2～3日となる.イエバエの発生期間中の各月,5月から10月まで,1回ずつ24～55対(5月には9対のみ)のイエバエを1対飼育して,平均未経産期(=前産卵期間)(範囲)及び以後の平均産卵間隔(範囲)を調べた結果は以下の通りである.5月:11日(8～20),7日(4～16) 6月:8日(4～11),4日(2～6) 7月:5日(4～10),2日(2～4) 8月:5日(3～12),3日(2～4) 9月:5日(5～10),3日(2～10) 10月:8日(6～9),4日(3～7)この成績表から第3表に示すように各月におけるCalendar ageを模式的に決定した.このCalendar ageを用いて,1964年にダイアジノン,ナンコール及びバイテックスで残留噴霧を行なったS,H,及びO部落で残留噴霧前後にある間隔で採集した各回の個体群の年令構成を吟味し,各部落における年令構成の経日的変化を部落間で比較してみると,経産雌の現われ方がS部落で最も遅く,H部落でやや早く,O部落で最も早いことが判ったが,この傾向は同年同期間中ハエ格子で調べた各部落でのハエ指数の消長とかなりよく一致した.従って1964年に上記3部落で実験した限りでは,ダイアジノン,ナンコール,及びバイテックスの順に効果があったといえる

Treatment of Wolbachia pipientis Infection with Tetracycline Hydrochloride and the Change of Cytoplasmic Incompatibility in a Nagasaki Strain of Culex pipiens molestus

A wild type strain of Culex pipiens molestus, which was originated from one egg raft collected by an ovi-trap in Nagasaki, Japan in 1980 and maintained at an insectarium of 25℃ and 70% RH, was cured by exposing the first instar larvae to 2.5-5%, 5%, 10%, and 20% water solutions of tetracycline hydrochloride for 20-48 hours befor food was added. Only one out of 12 lines of the strain has been cured of the Wolbachia infection when it was treated by 5% solution for 24 hours. Although treated and aposymbiotic (or Wolbachia free) females produced viable progeny when they mated with aposymbiotic males, no progeny was produced by the females when they were backcrossed with the original males with symbiotes. The newly established aposymbiotic strain has been maintained for over 11 generations

Improved Types of the Horse Meat Baited Fly Trap and the Fly Emergence Trap

The horse meat baited fly trap and the fly emergence trap (the Yoken traps) were improved and described in detail. The horse meat baited trap is for use in the field to observe the abundance of attracted adults and the breeding period of flies. The emergence trap is used to know the time of the adult emergence from the prepupae and pupae that have been found in the sand in the baited fly trap. By using these traps concurrently, the life cycle of blow flies would be properly studied

Life Cycle of an Oriental Blow Fly, Lucilia porphyrina (Walker) in Nagasaki, Western Japan

An investigation was made of the life history of Lucilia porphyrina (Walker) in Nagasaki prefecture, Western Japan from January, 1990 to December, 1992. A trap baited with horse meat was maintained at each of 3 altitudes, 5m, 500m and 1,000m, on Mt. Gokahara-dake. The number of flies captured was recorded once a month. The larvae and pupae which had bred from meat in the trap were also counted and transferred into a separate trap for emergence. The upper region of the mountain was considered as a primary habitat of this blow fly. At all altitudes, mature larvae were observed to enter dormancy/diapause in fall. Before winter adult flies at higher altitudes probably migrate to lowland for hibernation. After hibernation, males and females copulate, and females migrate again to highlands for oviposition during spring and early summer. During summer the highland seems to be the main habitat because all life stages were observed, while the lowland trap held only dormant/diapause larvae in summer. These latter individuals pupated and emerged in September

Transmission Dynamics of Dirofilaria immitis in a Southwestern Part of Japan

The transmission dynamics of Dirofilaria immitis were studied by using reported data in Nagasaki City and Omura City, Japan. The catalytic model was applied to the age distribution of positive rate for microfilariae of D. immitis in dogs. Using the force of infection obtained by applying the catalytic model, the critical vector density for the disappearance of D. immitis was estimated. Transmission frequencies of D. immitis in the two places were calculated by densities and infective rates of the principal vector, Culex pipiens pallens, and numbers of infective larvae of D. immitis in the vector. Roles of some factors influencing the transmission frequency of D. immitis were also evaluated with a simple mathematical model, and it was concluded that the continuation of extensive infection with D. immitis in dogs in spite of the presumed decrease of the vector density in recent years is ascribable to the increase of dog density and the increased protection of humans from mosquito bites

長崎市の飼い犬の飼育環境と人畜共通寄生虫，犬糸状虫の予防の実態に関するアンケート調査

犬糸状虫の感染と犬の飼育環境や飼い主の予防の実施の有無との関連性の手がかりをつかむため，1989年と1993年に長崎市の南部の戸町地区と北部の坂本，高尾，山里の3地区の320名または397名の飼い主を対象に犬の飼育環境と予防の実態についてアンケート調査を実施した．1989年と1993年の回収率はそれぞれ65.9％または55.9％であった．感染率の低い北部3 地区では家の中で犬を飼うと答えた人が多かった．感染率の高い南部の1地区では庭で犬を飼う人が多かった．このことから南部の犬は北部の犬に比べて主要伝搬蚊であるアカイエカに刺される機会が多くなることが推測される．予防措置としてはどの地区でも蚊取り線香が高頻度に使われていることがわかった．予防薬を投与している飼い主は一般に少なかった．To examine the role of living environments of domestic dogs and the measures taken by dogs owners to protect their dogs in the prevention of Dirofilaria immitis infection, we carried out a questionnaire survey in Tomachi (from the southern part of Nagasaki City) and Sakamoto, Takao and Yamazato (from the northern part of the same city) in 1989 (for 320 dog owners) and 1993 (for 397 owners). The percentage of dog owners who answered to the questionnaire was 65.9% in 1989 and 55.9% in 1993. In the northern 3 districts where positive rates the percentage of larvae-carrying dogs were low, dogs were often kept indoors. In the southern district (Tomachi) where the positive rate was high, dogs were often kept outdoors (in the yard). The high percentage of dogs kept outdoors in Tomachi seems to have increased the exposure of dogs to main vector mosquito, Cx. p. pallens. In all districts, mosquito-repellent coils were most frequently used as a means to control mosquitoes. The percentage of dog owners who used preventive drugs tended to be low

日本脳炎ウイルスに対する日本産蛇の感受性の検討

No virus could be isolated from sera of 305 wild snakes captured in nature, but hemagglutination-inhibition antibody was found in 6 of 270 snakes only at low titer. Sixty-four snakes were inoculated with JE virus, at various temperatures and attempted for virus recovery from the blood of them at intervals of 1-7 days during the experimental periods of 27-40 days. In only five cases the virus was recovered once for all on the third day (two cases), on the fourth day (one case) and on the sixth day (two cases) after inoculation. HI antibody developed in just one of 60 snakes at low titer, however, no response of NT antibody could be observed in 15 paired sera. These findings seem to imply that the common wild snakes in Japan are low susceptible to JE virus and they are in turn considered to play a minor role in epidemiology of Japanese encephalitis.1967年4月から10月にかけて採取されたヤマカガシ213匹,アオダイショウ28匹,シマヘビ49匹,ヒバカリ6匹,ジムグリ4匹,マムシ4匹合計305匹から日脳ウイルスの分離を試みたがすべて陰性であった.これらの蛇のHI抗体保有はアオダイショウ3匹,シマヘビ2匹,マムシ1匹に10乃至40倍という低い値であったがこれが真にHI抗体か否かはなお検討の要が考えられた.59匹の蛇を用い実験的感染を試みた.感染には10^MLD_の日脳ウイルスを腹腔内に接種し,25℃,室温,15℃,4℃の温度条件で飼育,また途中でウイルスの活性化を目的とし低温飼育から高温飼育に環境を変化させることも行なった.ウイルス接種後,数日おきに採血し,ウイルス血症の有無,HI抗体の上昇を検査した.ヤマカガシ2匹が,ウイルス接種後3日目と6日目に,シマヘビ1匹は5日目に,ヒバカリ及びジムグリのそれぞれ1匹が4日目と6日目に血液からウイルスが分離されたがそれ以後はウイルスの分離は出来なかった.平均30日後のHI抗体上昇の検査ではヤマカガシ28匹中1匹のみに10倍という低い値を示した.以上の事実から蛇の日脳ウイルスに対する感受性は予想以上に低いことが考えられるが蛇の日脳ウイルス増巾に果す役割は,ウイルス感染系路,飼育条件,抗体様成分の解析を吟味し検討した後明かにされるであろう.しかし今後,蛇以外の冷血動物に関しても広汎な実験を行う必要がある

日本脳炎伝搬蚊、特にコガタアカイエカの生態 : 2.終夜採集法による夜間吸血活動性と吸血嗜好性

All-night-catches of mosquitoes were made four times at human huts, by human-baited-traps, at animal sheds, and by dry-ice-traps, two times in June and once in September, 1965 and once in August, 1966. The hourly distributions of the collected females of Culex tritaeniorhynchus usually had a high post-sunset peak, and occasionally a low peak before or around sunrise. It was also shown that the order of mosquito species in the appearance of the post-sunset peak, early to late, is as follows: Aedes vexans nipponii, and Armigeres subalbatus>Anopheles sinensis, Culex neovishnui, and C. tritaeniorhynchus>C. pipiens pallens. As for the host preference of mosquitoes, it was shown from the percentage compositions of mosquitoes collected by various methods that C. tritaeniorhynchus, An. sinensis, Ae. vexans nipponii, and Ar. subalbatus are zoophilic; C, neovishnui is ornithophilic and zoophilic; and C. pipiens pallens is ornithophilic and anthropophilic.1965年6月と9月及び1966年8月に,人またはドライアイスを用いたトラップにより,あるいは豚舎,牛舎または鶏舎において,計4回の蚊の終夜採集を行なった.コガタアカイエカ雌成虫の採集数の時刻的消長には,多くの場合には日没後にピークが見られ,ある場合には日出前後にも小さなピークが見られる.日没後のピーク出現の時刻は蚊の種類により違っていて,次の順序である:キンイロヤブカ,オオクロヤブカ>シナハマダラカ,シロハシイエカ,コガタアカイエカ>アカイエカ.種々の方法で採集した蚊の種類構成から,吸血嗜好性を判断すれば,次の通りである:コガタアカイエカ,シナハマダラカ,キンイロヤブカ,オオクロヤブカは大動物嗜好性;シロハシイエカは鳥類嗜好性及び大動物嗜好性;アカイエカは鳥類嗜好性及び人類嗜好性

日本脳炎伝搬蚊,特にコガタアカイエカの生態5.コガタアカイエカとシナハマダラカの越冬

The time of awakening from winter diapause in Culex tritaeniorhynchus summorosus and Anopheles sinensis was examined from the data of mosquito catches in winter and early spring from 1965 to 1971 in the Nagasaki area. The results indicated that at least until the end of February most females of G. t. summorosus are still in a diapausing state, i. e., they do not feed on animals even on a warm day, while many of An. sinensis females are in such a physiological state already in January that they can feed on animals if the temperature is high enough for their flight activity. From the observations in the field and the experiments in the laboratory, it was implied that the main overwintering place of C. t. summorosus, and probably An. sinensis too, is the underground small space of stone walls, banks and the likes which are common in the terraced rice field area.コガタアカイエカとシナハマダラカの雌成虫が冬期の休眠から覚醒する時期を,長崎地方で1965-1971年の冬及び早春に採集した蚊の資料を用いて吟味して,次の結果を得た.コガタアカイエカの大多数の雌成虫は少なくとも2月の末までは休眠状態にあり,暖い日であっても吸血に来ることは殆んどない.これに反してシナハマダラカの雌成虫の多くは1月には既に休眠から覚醒していて,気温が飛翔活動に充分なほど高くさえあれば,多数の吸血蚊が観察される.野外及び実験室での観察から,コガタアカイエカが(そしておそらくシナハマダラカも)越冬するのは,階段状の水田が多くある地方の石垣や土手などの中の小さなすき間であるように思われる

日本脳炎伝搬蚊,特にコガタアカイエカの生態 : 3.コガタアカイエカがドライアイスに誘引される時刻の季節的変化

The time of being attracted to dry ice of Culex tritaeniorhynchus females in the evening roughly depends on the sunset time. Strictly speaking, however, the former time much fluctuates seasonally than the latter time. In spring, the starting time of being attracted to dry ice is usually over half an hour earlier than the sunset time, and the peak time appears around the sunset time. With the progress in season, the time in relation to the sunset time becomes later gradually and in summer and autumn the starting time, and consequently the peak time, becomes in most cases, later than the sunset time. In other words, the illumination in Lux at the time of being attracted to dry ice is much higher in spring than in the other seasons.コガタアカイエカ雌成虫が,夕方,ドライアイスに誘引される時刻は,季節的に,おおよそ日没時刻の変化に平行的であるが,厳密に言うと日没時刻よりも早い季節と遅い季節がある.春には,通常,日没の30分以上も前から誘引され始めて,日没頃に最も多く誘引されるが,季節が進むにつれておくれ,夏や秋には日没後に初めて誘引され始めるようになる.すなわち誘引される時刻の照度は,春の方が夏,秋に比分べて,一般に,はるかに高い