Azuki bean beetle (ABB), Callosobruchus chinensis (L.) is a field-to-storage pest of legumes and its female produces sex pheromone with two isomeric components, 2Z-homofarnesal and 2E-homofarnesal. Two day old virgin adults were exposed to 0, 200, 300, 400, 500 & 600 Gy gamma radiation and effect on longevity, fecundity, sterility and pheromone production were studied. Longevity (female; P < 0.001, male; P < 0.001) and fecundity (P < 0.001) were dose-dependently affected by the gamma irradiation. Both adults were totally sterilized by the tested doses of gamma irradiation as depicted by the null hatchability of laid eggs. Gas chromatography-mass spectrometry for solid phase micro extraction revealed that both of the pheromone components were significantly but not completely reduced by 300 Gy. It is a pre-requisite for a successful sterile insect technology that the sterility of ABB is induced without the total disruption of calling behavior.

The effect of increased carbon dioxide concentration in atmosphere was examined on the pheromone system of Helicoverpa armigera reared from egg stage to adult in three room. Two of three room (2×2×2 m) were treated with carbon dioxide gas as 600 ppm and 1,000 ppm, respectively. Mean of carbon dioxide concentration was 429.1 ppm in the control, 603.3 ppm for 600 ppm, and 1011.5 ppm for 1,000 ppm during experiment. Electroantenograph (EAG) test was conducted on 3-d-old male adults with air, hexane, and a series of their sex pheromone component, Z11-16Al, from 0.01 to 100 ng. The result was that male EAG responses of 600 and 1,000 ppm were 30.3% lower than that of control room. Production of Z11-16:Al was examined on about twenty 2-d-old virgin females. Carbon dioxide increases did not show a statistically significant difference. However, higher amount of sex pheromone was produced in females of 600 and 1,000 ppm. So, This experiment was replicated with different population reared again. The amount of the sex pheromone per female was 108.9 and 118.1 ng in control room, 139.8 and 141.8 ng in 600 ppm room, and 124.6 and 125.8 ng in 1,000 ppm room.

A cDNA of PBAN receptor (Plx-PBANR) isolated from female pheromone gland of the diamondback moth encodes 338 amino acids and has 7 transmembranes, belonging to G-protein coupled receptor family. The fact that Plx-PBANR expression was only found in female pheromone gland revealed that pheromone gland is the only molecular target of Plx-PBAN. Plx-PBANR expressing cells increased level of Ca2+ influx when challenged with PBANs. When RNAi fragment for PBANR was injected into pupae, suppression of PBANR expression was maintained for at least 2 days at post-emergence. Injection of RNA fragment for inhibition of Plx-PBANR expression also inhibited mating behavior and suppressed sex pheromone production, suggesting that some molecular target was affected by reduced Plx-PBANR expression. We cloned partial Δ9 and Δ11 desaturase gene and investigated expression level in Plx-PBANR-RNAi moth. It is of interest that desaturases expression was reduced by RNA fragment injection. These results suggest of PBANR expression affects the molecular biological events of PBAN and eventually suppresses mating behavior.

Sex pheromone production in lepidopteran is stimulated and regulated by a pheromone biosynthesis activating neuropeptide (PBAN). A cDNA of PBAN receptor (Plx-PBANR) isolated from female pheromone gland of the diamondback moth (DBM, Plutella xylostella (L.) encodes 338 amino acids. Plx-PBANR has conserved biochemical motifs and 7 transmembranes, indicating it belongs to G-protein coupled receptor family. Plx-PBANR expression was only found in female pheromone gland, demonstrating that pheromone gland is the only molecular target of Plx-PBAN. Human uterus carcinoma (HeLa) was stably transfected with Plx-PBANR gene and its expression was confirmed by RT-PCR analysis. Plx-PBANR expressing cells increased level of Ca2+ influx when challenged with Plx-PBAN and Hez-PBAN from Heliothis zea. When RNAi fragment for PBANR was injected into pupae, suppression of PBANR expression was confirmed by RT-PCR and maintained for at least 2 days at post-emergence. Injection of RNA fragment into pupae for inhibition of Plx-PBANR expression also inhibited mating behavior, revealing that reproductive organ of the female has no spermatocyte and that there are no successful reproductive behaviors. These results suggest of PBANR expression affects the molecular biological events of PBAN and eventually suppresses mating behavior.

A cDNA of PBAN receptor (Plx-PBANR) isolated from female pheromone gland of the diamondback moth (DBM, Plutella xylostella (L.) encodes 338 amino acids. Plx-PBANR includes 7 transmembranes, indicating it belongs to G-protein coupled receptor family. Plx-PBANR showed high similarities with other moth PBANRs and its expression was only found in female pheromone gland, demonstrating that pheromone gland is the only molecular target of Plx-PBAN. To accomplish the funcional expression of Plx-PBANR, Human uterus carcinoma was stably transfected with Plx-PBANR gene and Plx-PBANR expression was confirmed by RT-PCR analysis. Plx-PBANR expressing cells increased level of Ca2+ influx when challenged with Plx-PBAN and Hez-PBAN from Heliothis zea, as ionomycin as a positive control does. To inhibit Plx-PBNAR expression in vivo, RNAi fragment for Plx-PBANR was injected into pupae. Suppression of PBANR expression was confirmed by RT-PCR and also induced inhibition of mating behavior in adults, revealing that reproductive organ of the female has no spermatocyte and that there are no successful reproductive behaviors. RNAi-treated adults showed reduced pheromone production. These results suggests that inhibition of PBANR expression affects the molecular biological events of PBAN and eventually suppresses mating behavior.