[in Japanese]

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Some species of aphids are known as social insects. In social aphids, altruistic individuals called “soldiers” perform colony defense and housekeeping. Tuberaphis styraci, which lives in colonies inside plant galls, is a social aphid with sterile soldier caste. In T. styraci, younger soldiers preferentially perform housekeeping while aged soldiers exclusively perform colony defense, exhibiting a division of labor according to soldier age. We identified two aphid pheromones, corpse-recognition pheromone（linoleic acid） and alarm pheromone （trans-β-farnesene）, and two plant-gall allelochemicals, alarm signal （trans-2-hexenal） and “home sweet home” signal （linalool）, which mediated defense and housekeeping communications in this species. New soldiers preferentially responded to the corpse-recognition pheromone by performing cleaning behavior. Young soldiers chieｆｌｌy responded to the corpse-recognition pheromone and alarm signal by performing cleaning and attacking behaviors. Aged soldiers mainly responded to the alarm pheromone by performing attacking behavior. This age-specific behavioral response can explain the age-dependent division of labor in this species. Notably, when the concentration of each pheromone and allelochemical was elevated in the colony, soldiers were able to perform all kinds of tasks regardless of their age. Combination of alarm signal and alarm pheromone promoted attacking response of soldiers, while “home sweet home” signal inhibited their alarm response and so appeared to relax the aphids and diminish social disruption inside the galls. T. styraci regulated task allocation by utilizing various pheromones and allelochemicals and exhibited a flexible division of labor. Based on these results, we discuss the ecological and physiological mechanisms that coodinate the aphid social system.

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Social insects rely heavily on pheromone communication to maintain their sociality. Egg protection is one of the most fundamental social behaviours in social insects. The recent discovery of the termite-egg mimicking fungus ‘termite-ball’ and subsequent studies on termite egg protection behaviour have shown that termites can be manipulated by using the termite egg recognition pheromone, which strongly evokes the egg-carrying and -grooming behaviours of workers. We found that the termite egg-recognition pheromone consists of β-glucosidase and lysozyme. Both enzymes are major salivary compounds in termites and even in a wood-feeding cockroach, and are also produced in termite eggs. The fungus mimics termite eggs chemically by producing the cellulose-digesting enzyme β-glucosidase. Recently, a queen-produced volatile chemical consisting of n-butyl-n-butyrate and 2-methyl 1-butanol was identified as a termite queen pheromone that inhibits the differentiation of new neotenic reproductives in Reticulitermes speratus. In addition, the same volatile chemical is emitted by eggs themselves and plays a role both as a worker attractant and inhibitor of reproductive differentiation. By using the mechanism of egg mimicry, we developed a novel technology to introduce pesticide into the centre of termite nests and destroy the colonies most efficiently.

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Termites are famous for wood-destroying insects, and also for eusocial insects. They play an important role in ecosystem because of their unique symbiotic system with microorganisum. This review showed relations between taste and odor reception of termites on their sensilla, and their feeding and trail-following behaviors. The structures of natural compounds affecting the feeding repellent and trail-following are discussed.

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Various pest insects （hygenic pest, stored insect, and agriculture and forestry pest insect, etc.）exist in our living environment. They invite the deterioration such as qualities such as diets on the hygiene side of the person, and become big problems. As measures, there is problems such as persistencies and safety probabilities, and the method of using an environment-friendly natural substance, for instance, the fragrance components are paid to attention though a lot of synthesized chemical substances that have an excellent control action are developed. When the plant puts the root on a part and the earth, moving cannot be taken. Therefore, the chemical substance with a high control effect and safety probability has been generated as a method for correspondence to the attack such as peripheral microbes and insects. Here, the focus will be appropriated to the chemical substance with a high insect pest control function that the plant produced to consider those use, and it outline it.

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Artificial odorant is attached to city gas, which is originally odorless, in order for customers to detect gas leakage by their own olfaction. In this study, we noted indispensable aspect as city gas odor, which is “city gas odor should be hard to cause olfactory fatigue”. We defined olfactory fatigue as “situation under unidentification for odor quality, caused by continuous odor’s exposure”. And we tried to provide customers useful information about time-course transition of olfactory fatigue for city gas odor under city gas company’s leading.
First, using tertiary-butylmercaptan (hereafter, TBM) which is main ingredient of city gas odor, we performed real-time evaluation of perceived intensity to continuous odor’s exposure, And obtained time-course transitional approximation of olfactory fatigue, calculated by perceived intensity. This analysis showed that the time for olfactory fatigue among half customers would be about two minutes, after exposure to city gas odor.
Secondly, we performed the same evaluation mentioned above for additional three odorants familiar in Japanese daily life, and compared time-course transition of olfactory fatigue among TBM and three daily odorants. Results implied that TBM does not remarkably caused olfactory fatigue more easily than other odorants. Accordingly, we concluded that TBM was an odorant suitable for city gas odor.

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We have been developing many kinds of headspace（HS）sampling techniques （Aeroscent Technology^®）toward reconstructing natural aromas as if we really feel them. β-damascone（1-（2,6,6-trimethyl-1,3-cyclohen-1-y1）-2-buten-1-one）and β-damascenone （1-（2,6,6-trimethyl-1,3-cyclohexadien-1-y1）-2-buten-1-one） are the key rose- odor compounds and have extremely low-odor threshold values. Although the detection of these compounds from rose essential oils has previously been reported by many researchers, the odorants have not been directly detected from living rose fowers. Thus, we attempted to detect these compounds from living roses （Rosa damascena Trigintipetala）using improved HS sampling techniques based on two typical HS analyses（Tenax adsorption tube method and Stir Bar Sorptive Extraction method）. As a result, both β-damascone and β-damascenone were detected only by the improved Tenax tube method under the optimized conditions ; 1）at the most fragrant time of rosy scent by sensory evaluation （late morning, about 10 a.m.）2）. using Tenax 2000 mg tube（10 times volume as much as normal tube）and 3）using a heat fractionation operation（150°C,5min）This method is very effective for understanding the relationship between sensory evaluation and aroma components of rose fragrance.

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