In this paper, the observations of the ecology of a Limantrid moth, the Far Eastern urticating moth, Euproctis flava Bremer, made throughout the life cycle in laboratory and in field are reported. Overwintering in larval stage, this species has a generation in a year (Table 1). The mean duration of each life stage is shown in Table 2. Pupa, adult and egg are found during summer season, as these stages are rather short, the larvae can be seen almost throughout the year. The female moth usually deposits her eggs in a single mass, preferably on the under surface of a leaf. An egg-mass is covered with the hairs of her anal tuft. Each mass contains 200-1, 000 eggs. A female moth can oviposits 1-3 times during her life, therefore 300-1, 500 eggs are produced by a single female. As shown in Table 3, the hatching ratio are favoured in a higher humidity. After hatching, the young larvae gather to a tight colony, until as late as the late autumn, but after hibernation, they tend to scatter to all parts of the trees and the surroundings, entering into a solitary life. The number of larval moultings varies between eleven to seventeen. The number of instars may be influenced by various environmental factors such as : local distributional factor (probably due to the temperature), seasonal disparity of the oviposition time, suitability of the food plant, and the larval population density; further by the difference of sex and the presence of parasitic natural enemies. The period of each instar duration is shown in Table 4. The larvae on an stage of between 9-13 instars hibernate within a winternest, which is spun on the ground or among dead leaves. The records of the entering to and the awakening from hibernation are shown in Tables 5, 6, and 7 and Figs.2 and 3. A mature larva leaves the food plant to seek the pupating site, where they spin a rather loose cocoon and pupate therein. The moth usually emerges out from pupal skin between the hours of 13 : 00 to 16 : 00 in the afternoon, male moths emerge 5-6 days earlier than the females do. The adult insects take no food. The mating takes place in the night-times immediately after emergence, and about 3 days after the mating, the female begins to deposit eggs. The list of food plants, including previous author's records, is shown in Table 8. But, younger instar larvae show tendency of preference to several plants, for example, Quercus spp., Rhododendron spp., Rosa spp., Polygonum spp. and etc. When breeding parallel crowded cultures on different food-plant, marked differences were observed in the rates of larval development and the larval body colour. The result obtained with four different food plants : Quercus serrata, Rhododendron linearifolium, Prunus yedoensis var. macrosepalum and Celtis sinensis var. japonica, for 100 larvae crowded cultures, are given in Fig.7 and Table 9. The results clearly showed that the food-plant can affect the development and colour composition of larva. Larvae reached maturity on Prunus fewer one instar than Quercus and Rhododendron. Larvae bred on Celtis died all until 10th instar. In order to analyse the variability of larval colour pattern, four colour groups were divided, based on the extent of the dorsal black markings on the third to the seventh abdominal segments (Fig. 6). The result shows that the colour composition and the mean colour are affected by the foodplant; Quercus resulting in the darkest with a group mean of 1.78, whilst Prunus produced the lightest with a mean of 2.38. Some effects of population number in association were determined by the comparing of different cultures under solitary to crowded conditions. Larvae of cultures bred less than 10 larvae in association, died all before 8th instar, the culture of 20 larvae reached maturity in 15th instar, whilst that of 50 and 100 larvae in 16th instar. As regards to the variation of colour pattern, the culture of 100 larvae became the dar

(View PDF for the rest of the abstract.)

View full abstract

In this paper, the author argues the epidemiological character of the Far Eastern urticating moth, Euproctis flava Bremer, and describes the mode of injury caused by the insect, based upon the cases reported in Tokyo. Of the ten species of Japanese Euproctis species examined, it was recognized that E. similis, xanthocampa, piperita, pulverea, kurosawai, pseudoconspersa, staudingeri hold the urticating spicules in the anal tuft, similarly as flava does. But, it has not been proved on E. torasan and curvata, of which each only a male adult specimen was examined. The two species, E. flava and pseudoconspersa, are believed to be considerable pest of medical importance, in this country. Occasionally, E. flava abnormally breaks out in a large area, while E. pseudoconspersa, frequently occurs locally on the yard of residences in the suburbs of larger cities. The cases of injury caused by E. flava in Tokyo, 1956-57, may be summarized as follows. The majority of victims was housewives and followed by the salaried men and students. The majority of the injure-cases took place indoors, between the hours 18 : 00 and 24 : 00. The dermatitis appeared oftener on arm, then neck and breast. The injuries caused by egg, larva and pupe were seldom.

View full abstract

1. A series of investigations have been made on the bionomics and life history of the dermatitiscausing beetle, Xanthochroa waterhousei Harold, Collections and observations were made at various localities of Japan. 2. Adults of the present species is distinguished from those of allied species mainly by the structure of the apical part of abdomen. Larvae are characterized by possessing asperated ambullatory ampullae on the dorsum of three thoracic and first two abdominal segments as well as on the venter of 3rd and 4th abdominal segments, though in the first instar they are inconspicuous. Eyes of the last instar larvae absent, but 2 pairs of ocelli are discernible in the first instar. Eggs are subcylindrical, tapering towards both rounded tips, somewhat curved in whole shape, milky white in colour and 1.3 to 1.4mm in length. 3. The seasonal occurence of the adults varied by the localities, but was confined to early summer as the principle. In warmer parts of Japan such as in Kyushu, they could be collected from April to June; in Tokyo and in Kobe from May to July; in the mountains of Honshu as well as in Hokkaido where the climate is colder, they were found to be active until September. In other words, the seasonal distributions of the adult beetle and occurence of the dermatitis seem to be much influenced by the local climate, i. e. they appear earlier in season as climate gets warmer. 4. Diurnal activities of the adult beetle in nature was investigated. In the daytime, they usually stay still beneath leaves of trees. They become active towards evening and often fly around chestnut flowers in swarms. Through field observations, feeding experiments and dissections of the digestive organs, they were found to feed mainly on pollens of various kinds of flowers. 5. The results of light trap collections made repeatedly at Narimasu, Tokyo, showed that activities of the beetle were confined mainly in the first few hours of the darkening or of the premidnight type. 6. Secretions of the poisonous or dermatitiscausing fluid of the adult beetle (determined by the author and Watanabe as cantharidine) take place by compression on any part of the body. The fluid may be secreted from sublateral parts of the anterior and posterior margin of pronotum, longitudinal costae of elytra or the tip of each tarsus. 7. During copulation, a male stays on the back of a female in a parallel position. However, some of the females were often found to ride on other females and protrude their ovipositor, acting as if they were males in mating positions. 8. Females in cage insert their long ovipositor into narrow crevices and deposit eggs in a mass. Eggs are covered with a glutinous substance and are abhesive to each other. The numbers of eggs in a cluster varied from 56 to 221 in five times of observations. The incubation period was 7 to 14 days under the room temperature of 13.9℃ to 31.6℃. 9. Larvae in nature were found to burrow into rotten timbers of Sugi-tree (Japanese ceder) making holes just above or beneath the soil surface. In a laboratory breeding experiment, first instar larvae kept with the rotten timber emerged in May of the following year. The beetle seems to pass one generation in a year. 10. In the daytime collections in nature, the sex ratio of male to female was 43 to 57. In the light trap collections, males were much fewer than females only 2% of the total. Attractiveness towards the light source seem to be much stronger in the female.

View full abstract

Paederus fuscipes Curtis is the poisonous beetle which frequently causes an acute human dermatitis in Japan as well as in number of foreign countries. The author has made experimental and field observations on the life history, bionomics and distributions of the species in Japan. External structures of each developmental stage have also been fully described. The life cycle of this species comprises egg, larva (two instars), pupa and adult. Adults are about 7mm in length, and look like ants. Free pupae are about 4.5mm in length; body slender and curved ventrally, milky white to orange yellow in colour, with a pair of long seta-like processes on the anterior and posterior margins of pronotum, lateral margins of 1st, 3rd to 7th abdominal segments respectively. The second instar larvae are 4 to 6mm in length; body subcylindrical, white to orange yellow in colour, with a pair of urogomphi. The first instar larvae are 2.2 to 3.4mm in length. Eggs are subspherical, 0.6 to 0.7mm in diameter immediately after the oviposition, but increase in size as the development proceeds. The species is widely distributed throughout Japan, from Hokkaido to Kyushu. It seems to be more abundant in warmer regions. The adults are usually found on soil surface or on grasses in dump places, such as marsh or rice-field. At Narimasu, Tokyo, they could be collected by a light trap during the season from the end of April to the end of October, having the peak in June and July. The nocturnal activity of the adults belongs to the pre-midnight type, i. e. more than half of the total number of a night collection by the light trap was obtained within two and half hours after it had become dark. Eggs are usually laid singly into the crevices on the soil surface. The numbers of eggs deposited by a female were from 18 to 100 with the mean of 52.3. Females which overwintered began to lay eggs from the end of April or from the middle of May to July. Those which emerged in early June continued to lay eggs from July to September. Incubation period of eggs were 3 to 19 days. Hatching rate observed was 96.2%. Larval stage consists of only two instars, the duration being 4 to 22 days for the first instar and 7 to 36 days for the second. Pupation takes place in a chamber constructed beneath the soil surface. Pupae are held up off the wet floor of the chamber by seta-like processes on the pronotum and abdominal segments. Pupal stage was 3 to 12 days. The total development from egg to adult required 22 to 50 days, with an average of 32.5 days. Adults are polyphagous in their food habits, feed mainly on insects, mites and soil nematodes, but also on dacayed vegetables in nature. The food habits of larvae are similar to the adults, mainly carnivorous as a rule, but could experimentally be reared with either beef or cucumber. Adults are eaten by frogs and parasitized by a namatode, a mite (hypopus stage) and Laboulbenia cristata. Eggs and larvae are attacked by various kinds of predacious insects and spiders. The annual life cycle was rather irregular around Tokyo, either one, two or three generations in a year. The adults were the only stage which could be recovered during hibernation. They often form clusters during the overwintering period. The poisonous substance which causes dermatitis could be detected in every part of the body of adults, pupae, larvae and eggs. It is contained in the body fluid, and leaks out only when a part of the body is injured. Among eight species of the genus Paederus found from Japan, four species, i. e. fuscipes, tamulus, poweri and parallelus were found to contain the poisonous substance, but fuscipes seemed to be the only species of practical importance. Out of 68 species of Staphylinidae collected by light traps in Japan, Paederus fuscipes was also found to be the only species of actual importance as the cause of human dermatitis, though a few others were demonstrated to cause slight skin lesions under experimental conditions.

View full abstract

Recent collections of small mammals in Hokkaido have revealed the presence of four species of fleas not previously reported from this island. Two of these species are recorded from Japan for the first time. Additional collections will probably demonstrate that these species are common elements in the flea fauna of certain regions of Hokkaido, but they may be restricted to special habitats or certain seasons of the year.

View full abstract

In this article the status of Megabothris asio nakamurai Ono, 1955 is discussed, and the occurrence of this flea is reported from Honshu (the northern part of the Japan Alps, Nagano Prefecture). One pair of this form was collected from Rattus norvegicus and Microtus montebelli on May 31, 1957 by the author. Megabothris asio has been divided into three subspecies : asio, megacolpus, and nakamurai. The first two forms are Nearctic and the last was described from Hokkaido (Rebun Island) from Clethrionomys rufocanus. The relationship of the Japanese form seems closer to Megabothris sokolovi, and should porperly be called Megabothris sokolovi (Gershkovich, 1953). This rocord is another example of the similarity of species of Eastern Asia and Eastern North America.

View full abstract

The surveys were carried out by the authors at several areas in Fukui Prefecture during the period of 21 months from April, 1953 through December, 1954. Analysis of relationship between hosts and trombiculid mites, epidemiological and taxonomical aspects of the results obtained by the surveys were described in this report.

View full abstract

In order to explain the variability of the effect due to various application technique of spot treatment using residual insecticides this investigation was carried out against cockroaches. This general method was employed by the author (1957) who used a model method, which seemed to give a condition similar to natural environment to adult German roaches used. Acetone solution of DDVP, γ-BHC, dieldrin and DDT are used in this test. It was experimentally confirmed that the satisfactory effectiveness could obtain so far as a insecticide has been applied on the surface of the shelter of the cockroaches or its adjacent objects. But, as regards the contact effect of spot treatment of DDT, the same fact is not always true. Because the efficiency of DDT against cockroaches is always lower than any of other compounds. However, if untreated concealment of the cockroaches is left, the effectiveness of any of the compounds is strongly influenced.

View full abstract

Laboratory tests were conducted to determine the effects of several insecticides against two species of cockroaches, Blattella germanica L. and Periplaneta japonica K.. The result are summarized of follows : Topical application method : By the application of 18μg per roach of the toxicants allethrin, DDVP, γ-60% BHC and diazinon, gave higher knockdown effcets than lindane and malathion. Those of dieldrin, aldrin and endrin were inferior to the above insecticides. Crude DDT and p-p' DDT caused no knockdown effect for five hours after treatment. However, in the mortality after 24 hours, dieldrin aldrin, endrin, allethrin and DDVP were almost at the same level and were more effective than the other chemicals. Similar results were obtained by treatment with 1.8μg per roach of toxicants except allethrin, which showed fairly low effect at this doses. Contact method : When Blattella germanica was brought into contact with glass plate of 100cm^2 treated by 0.5cc of 1% aceton solution of the toxicant, the order of knockdown effect was as follows : Allethrin>DDVP>γ-60% BHC>diazinon>lindane, malathion>dieldrin, aldrin, endrin, crude DDT, p-p' DDT. And with filter paper treated by the same amount of toxicant, the order changed as follows : DDVP>γ-60% BHC>allethrin>lindane, diazinon>dieldrin, endrin, crude DDT>malathion, p-p'DDT. During the observations on the mortality at 6 days after the treatments, DDVP, γ-60% BHC, diazinon, lindane and allethrin were only slightly more effective than the other chemicals, and all the chemicals tested showed of mortality over 95%. In the tests on the relationship between the time of exposure and the mortality with different insecticidal residues, dieldrin showed highest effects as 100% kill by 5 minute's exposure, while the similar effects were observed by 1 hour's exposure of diazinon and lindane. DDT was less effective on both B. germanica and P. japonica than the other chemicals through the test method discussed above.

View full abstract

LC-50s of various insecticides to mosquito larvae of some species collected from Tokyo district in 1952, 1953, 1956 and 1958, from Amami Oshima island in 1958, and from Bangkok in 1957, were obtained and compared with those of other foreign authors. Against Culex pipiens pallens and Aedes aegypti parathion was most effective, dieldrin was the next and the organic phosphorus insecticides, i. e. diazinon, DDVP and dipterex were the third. Aldrin, lindane and p-p'-DDT followed them. Aedes aegypti was three or four times more tolerant than C. pipiens pallens to every kind of larvicides used. While C. pipiens pallens showed stronger tolerance Armigeres subalbatus or Aedes albopictus to p-p'-DDT but they were nearly in the same level in the tolerance to dieldrin and lindane. It attracted the authors attension that A. subalbatus collected from Amami Oshima island where DDT had been heavily applied by U. S. Army was rather susceptible to p-p'-DDT, C. pipiens pallens and A. albopictus collected there were moderately resistant to the chemical, and by the other studies (Suzuki et al., 1958) also showed the same fact that also Musca vicina collected from the same district was resistant in high level. C. pipiens pallens collected from Tokyo district in 1958 was two to four times resistant against p-p'-DDT than the same species collected in 1952 or 1953, and comparing with the data obtained by foreign workers resistance was about ten times than C. pipiens fatigans, two to five times to lindane than collected in 1956 and about ten times than C. p. fatigans, three to twenty times to dieldrin than those collected in 1956, and ten to one hundred times than C. p. fatigans. As no dieldrin had been applied in the district, these increased resistance may be ascribed to the cross-resistance with lindane, which had been often applied for the control of mosquito larvae. To diazinon, one of the so-called organic phosphorus insecticides, the tolerance in C. p. pallens collected from Tokyo district in 1956 and 1958 was nearly in the same level. Aedes albopictus collected in 1958 was also about six times more resistant against p-p'-DDT than those collected in 1952 or 1953. Comparing the data presented here with those reported in foreign countries, A. albopictus collected from Tokyo district in 1958 and A. aegypti collected from Bangkok in 1957 were more tolerant than the same specimens in forign countries, especially on the latter species.

View full abstract

The protective effect of four repellents on the black fly, Simulium aokii Takahashi, 1941, were observed in the summer of 1958. The skin of calf or forearm of human was evenly covered by diluted repellents, such as diethyltoluamide, dimethylphthalate, MGK No.11 or MGK No.326 solution. Each repellent was diluted in ten times with pure ethylalcohol. Diethyltoluamide was most effective in four chemical tested. Ten percent solution of the chemical was effective throughout eight hours after the treatment. Any significant difference could not be shown in the efficacy between 10% and 20% solution of diethyltoluamide. But 10% cream of the chemical lost it's effect six hours after the treatment.

View full abstract