| The German cockroach, Blattella germanica, is one of the most important and undesirable domiciliary pests throughout the world. At present, roach control depends mainly on chemical pesticide.While the indiscriminate application of insecticide has led roaches to develop a resistant ability against the relevant chemicals.As a result, the roach control fall into a predicament, and the cost of control increased obviously.Aggregation pheromone is a kind of chemical medium released by roaches, which can make the individuals gathering to impair the sanitation. Unlike sex pheromone, aggregation pheromone can attract both males and females, nymphs and adults. Based on the unique characters of aggregation pheromone, an improved roach control may expected by adding the pheromone to some kinds of traditional blatticide baits. Many research woks have been contributed up to date on the aggregation pheromone of the german cockroach, but the main interest is only on the bio-activity and the chemical components of the pheromon, while nothing is known nowadays about the aggregation pheromone biosynthesis and its regulatory mechanisms.On the background described above, with the aid of a self-made olfactometer, both the cuticle and feces derived attractive activities of the german cockroach were studied to determine the origins of the aggregation pheromone. Then the active ingredients of the pheromone were extracted, and their chemical components and contents were analysed by gas chromato-graphy (GC) and gas chromatography-mass spectrometry (GC-MS). A series of regulating factors, such as pheromone biosynthesis activating neuropeptide (PBAN) secreted from the brain-suboesophageal ganglion (Br-SOG), juvenile hormone(JH) from the corpora allatum(CA), moulting hormone(MH) from the prothoracic gland(PG), and the photoperiod, were also studied on their influences to the aggregation pheromone biosynthesis. Furthermore, the allatostatin cDNA was cloned and sequenced by RT-PCR to find out the regulating mechanisms of pheromone biosynthesis on the molecular level.The main results are as follows: 1 The biological activity of aggregation pheromone1.1 The aggregation activity of whole roach bodiesThe results of choice-chamber test showed that all the nymphs, adults of both sexes can attracted and arrested the test insects. The males were not as attractive as nymphs and females. The attractability and arrestant activity of whole nymphal bodies to nymphs and female adults are very strong, and the aggregation index (AI) are 0.79 and 0.76, the retention index (RI) are 0.63 and 0.66, respectively. While the attractability and arrestant activity are weaker to male adults, the AI is 0.58, the RI is 0.52. When the lure is female adults, the attractability and arrestant activity to the three types of cockroaches are significant, and the Alto nymph, female and male adults are 0.79, 0.76 and 0.77, the RI are 0.67, 0.64 and 0.65, respectively. The whole male bodies showed a weak attraction and restraint to the same sex individuals, the AI is 0.33, and the RI is 0.41, while showed a relative stronger performance to nymphs and female adults,the AI and AI are 0.66, 0.70,and 0.60, 0.66,respectively. These results lead to the conclusion that German cockroach, regardless of instar and sex can secrete aggregation pheromone from the body surface, and the aggregation pheromone may consist of both attractant and arrestant components.1.2 The aggregation activity of cockroach faecesGerman cockroach's faeces is another kind of important origin of aggregation pheromone. The faeces are significantly more attractive and restrictive than the whole bodies. Comparing the three diiferent original faeces, the nymph's faeces are most attractive and restrictive, and the male adults' faeces are significantly less attractive and restrictive. The nymph's faeces are more attractive to female adults than to nymphs and to male adults, the AI is 0.91; while all the restrictive responses are stronger andhave no significant difference between them, the RI are 0.84, 0.87...
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