Seasonal fluctuation in numbers of the pine wood nematode, Bursaphelenchus xylophilus (STEINER et BUHRER) NICKLE, transmitted to pine from the bodies of adult Japanese pine sawyers, Monochamus alternatus HOPE, was determined from the simulation model proposed by TOGASHI (1980). Nematodes invaded the pine trees between mid-June to late-July, with the peak invasion in late-June. This peak appeared about two weeks after the number of adult beetles reached maximum. In the study forest, pine trees diseased by nematodes appeared before July 20 and 31 trees died before winter began. The date that a cumulative 50 percent of the trees were diseased was August 11, 56 days after a cumulative 50 percent of the nematodes invaded the pine trees.

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The temporal pattern in transmission of the pine wood nematode, Bursaphelenchus xylophilus, from its vector, the Japanese pine sawyer, Monochamus alternatus, to pine trees was investigated. Forty adult sawyers were raised on excised pine twigs to measure the number of transmitted nematodes and the area of bark consumed by a sawyer at 5-day intervals. Females fed on more food than males. The number of nematodes carried by the sawyer at emergence had no effect on its food consumption per unit time. Thirty-three sawyers showed unimodal nematode-transmission curves and two showed L-shaped curves. The averaged transmission curves of the sawyers carrying more than 10, 000, 1, 000 to 9, 999, and 100 to 999 nematodes had one peak of about 1, 500, about 370, and 38 nematodes per 5 days, respectively, which appeared during a period from the 20th to 35th day after emergence of the sawyer. No peak was obvious in the transmission curve of the sawyers carrying less than 100 nematodes. The percentage of nematodes remaining within a dead sawyer tended to increase as the initial number of nematodes carried increased.

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Nymphs of Carbula humerigera collected in the field at Hirosaki matured synchronously as adults from late June to early July. Females did not lay eggs before the summer solstice. Rearing under natural daylengths at 25°C indicated that increasing daylengths suppressed oviposition and decreasing ones promoted it. Nymphal diapause was induced in the third to fifth instars by short photoperod, apparently maintained by decreasing photoperiod, and terminated near the time of the winter solstice.

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At 25°C, the nymphal diapause of Carbula humerigera was induced in the second to fifth instars by short stationary photoperiods of 10 to 13 hr and averted by long of 14 to 16 hr. In a photoperiod of 13.5 hr, the nymphal development was transitional. At 20°C, the nymphal diapause was induced by a photoperiod of 14 hr or shorter and averted by photoperiods of 15 to 16 hr. The critical daylength lies between 14 and 15 hr. Therefore, temperature exerted a modifying effect on the critical photoperiod. The nymphal development was affected by changes in photoperiod and the adult emergence tended to be more synchronized by increasing photoperiod.

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In laboratory experiments, the rate of follicle development of horn fies increased in proportion to the temperature in the range from 24-30°C, though there was no difference between 30 and 32°C; the follicle developed little at 24°C. From the regression between mean follicle stages and days after emergence, it was estimated that the days from emergence to the first oviposition averaged 49.2 at 24°C, 15.4 at 26°C, 10.0 at 28°C, 6.4 at 30°C and 6.7 at 32°C. The blood meal volume per day increased in proportion to the temperature and in female it was higher than in male. Blood volume necessary for egg production in the first oviposition of a fly was estimated to be approximately 33 mg.

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Ultrastructural changes in the silk gland after an ethanol treatment and the encapsulation of the abnormal regions of silk glands by hemocytes were studied. Abnormalities induced by low doses of ethanol are restricted to several cells located in the most anterior region of the middle silk gland, and to the duct cells of the anterior silk gland. The affected regions are encapsulated by hemocytes. The ultrastructural abnormalities in the affected silk gland cells are detected within 24 hr after the ethanol treatment. Both types of hemocyte, plasmatocytes and granulocytes, attach to the basement membrane of the affected cells and form encapsulated sheath. During 24 to 120 hr after ethanol treatment the affected silk gland cells degenerate, and dense materials derived from the affected cells pass through the basement membrane. It should seem that the unknown substance passes through the meshwork of the basement membrane and attracts the hemocytes.

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A high activity of 3-phosphoglycerate dehydrogenase (E.C. 1.1.1. 95) was detected in the fat body tissues, midgut and silkglands of the silkworm, Bombyx mori, and the enzyme activity was the higherst in the fat body tissues. The enzyme activity was concentrated in the supernatant fraction obtained by centrifugation at 15, 000 g for 30 min, while a low activity of the enzyme was observed in the mitochondrial fraction. 3-Phosphoglycerate dehydrogenase was partially purified from the homogenate of the fat body tissues by column chromatography on DE₅₂-cellulose and Ultrogel AC₃₄, and the final partial purification was approximately 60-fold. The pH optimum for the enzyme reaction was 7.5, and the isoelectric point of the enzyme corresponded to pH 7.0. The K_m values were 1.1×10^-4 M for hydroxypyruvate phosphate and 3.6×10^-6 M for NADH, respectively.It is possible to substitute NADH with NADPH as a coenzyme for 3-phosphoglycerate dehydrogenase. The crude homogenate of the fat body showed a weak activity of the enzyme which promoted the reduction of hydroxypyruvate, but the partially purified preparation lost such activity. The participation of 3-phosphoglycerate dehydrogenase in the synthesis of serine and glycine for the silk-protein in this insect was briefly discussed.

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As part of the research on the nutritional physiology of the brown rice planthopper, the nutritive value of sugars for larval growth was studied. Hatched larvae were reared on an MED-I diet supplemented with one of the following sugars : sucrose, glucose, maltose, fructose, raffinose, or trehalose at concentrations of 5%. All larvae died within several days on diets supplemented any one of these sugars except sucrose. Larvae reared on diets containing glucose, fructose, or maltose grew to adults when the diet was supplemented with 1% sucrose, while those reared on raffinose or trehalose with an additional 1% sucrose still died within several days. When the larvae were reared on diets containing sucrose as the sole sugar, adult emergence depended on the sucrose concentration, which ranged from 3% to 50%. The shortest nymphal period was observed on the diet containing 5% sucrose.

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The neutral components of the pygidial defensive secretion in formic acid-secreting carabid beetles were identified by gas chromatography, mass spectrometry and infrared spectroscopy. Formic acid made up more than ninety-five percent of the secretion and neutral substances were minor components, less than five percent. There were two types of formic acid-secreting beetles in regard to neutral components : Platynini, Harpaline, Licinini, Lebiini and Odacanthini had 2-tridecanone, while Zuphini and Dryptini had decyl acetate, decyl formate and nonyl acetate. Component amounts differed among beetles of the same type.

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Luteolin-7-glucoside was isolated as a feeding stimulant to leaf beetles, Chrysomela vigintipunctata costella and Plagiodera versicolora distincta in addition to salicin from the leaves of Salix gracilistyla. Feeding response of three species of Salicaceae-feeding leaf beetles, C. v. costella, P. v. distincta and Lochmaea capreae cribrata, to the three chemicals, luteolin-7-glucoside, salicin and a salicin derivative, populin, varied species-specifically. Salicin and populin stimulated the feeding in C. v. costella and P. v. distincta but not in L. c. cribrata, while all three species responded to luteolin-7-glucoside.Salicin was found in all Salix species examined, and populin was always accompanied by salicin in the genus Populus. Luteolin-7-glucoside was also distributed in Salicaceae. These results suggest that host specificity of C. v. costella and P. v. distincta depends on the presence of salicin and populin as well as luteolin-7-glucoside. On the other hand, the cue substance in L. c. cribrata seems to be flabonoids such as luteolin-7-glucoside.

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Attractants and arrestants were recognized as playing an important part in host-plant selection by the yellow butterfly larvae, Eurema hecabe mandarina DE L'ORZA. The attractant for this insect was color, in contrast to odor for other lepidopterous larvae. The arrestant for the larvae was a mixture of chemical constituents in their host plant, Lespedeza cuneata G. CON, namely, D-pinitol, D-fructose, myo-inositoI, and probably cellulose.

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The oviposition releasing factors in Tineola were studied through several preference tests using various kinds of oviposition substrates. The female moths laid their eggs predominantly on fleecy substrates irrespective of whether they were wool or cotton. Wool was less preferred than cotton, probably because of greasy substances adhering to it. Certain limitations were demonstrated in the moth's preference as to the mesh size of wire gauze or the dimension of the gap between two glass plates which were used as oviposition substrates. Moths seem to sense the configuration of the mesh or the gap by means of mechanoreceptors distributed on the ovipositor; if the configuration is suitable then oviposition is released. All the evidence indicated the importance of the tactile, rather than the chemical, stimuli although the possibility of the latter in oviposition control cannot be excluded.

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We conducted two experiments on the oviposition strategy of the gregarious parasitoid, Apanteles glomeratus. First, we estimated the relationship between the egg number per host (N) and the reproductive sucess of the eggs in terms of dry weight of parasitoid offspring. The reproductive success gained from one egg was maximized when 10≲N≲20, while the reproductive success gained from one host attained its maximum when N⋍40.There are certain limitations in the egg supply and life span of a wasp, hence the number of hosts in which she can oviposit in her lifetime is also limited. Consequently, if natural selection favoured behaviour to maximize total reproductive success of all eggs laid by the wasp throughout her life, and if the wasp can estimate the host density by the frequency of host encounters, the number of eggs to lay in each host would be determined in the following manner. When the host density is low and there are few prospects of finding enough hosts in which to deposit all her eggs, the best strategy is to maximize the reproductive success gained from each host. On the contrary, when the density of hosts is high enough to deposit all her eggs, it is better to maximize the reproductive success gained from each egg. The result of the second experiment agreed with this prediction; when the wasps were offered the hosts at long intervals, they laid 35-40 eggs in each host, while when offered the hosts with high frequency, they reduced the egg number per host to ca. 20.

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Buprofezin (2-tert-butylimino-3-isopropyl-5-phenyl-3, 4, 5, 6-tetrahydro-2H-1, 3, 5-thiadiazin-4-one, Applaud[○!R]) showed toxicity to each developmental stage of the greenhouse whitefly, Trialeurodes vaporariorum (WESTWOOD). The larvae died within five days after treatment, showing abnormal molting. The LC₅₀s of buprofezin for the first, second, third, early and middle fourth instar larvae were 0.659, 0.482, 2.45, 11.6 and 15.7 ppm, respectively. Buprofezin was more excellent than chinomethionat, methidathion and fenvarerate in larvicidal action on all stages except the late fourth instar larvae (i.e. pupae). More slow-killing effect of buprofezin was observed on the adults. Buprofezin, being weak in ovicidal action, showed an effect on the adults to lay unhatchable eggs.

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