Abstract: The cotton bollworm, Helicoverpa armigera, mainly relies on sex pheromone communication for mate orientation and reproduction. The mechanisms of pheromone reception in H. armigera are the hot topic in the field of chemical ecology in China. In this article, we reviewed the reception mechanism to female sex pheromone in male H. armigera, hoping to provide references for further investigation of the molecular and neural mechanisms of sex pheromone perception in H. armigera and other related insects. In the sex pheromone glands of female adult, long-chain, saturated or unsaturated fatty aldehydes, and alcohols were synthesized, among which Z11-16∶Ald was used as the main sex pheromone component, while Z9-16∶Ald and Z9-14∶Ald as the secondary sex pheromone components. The blends of these components at certain ratios show enhanced attraction to male H. armigera. Z11-16∶OH and a high-dose Z9-14∶Ald inhibit the attractiveness of pheromone blends to male H. armigera. Correspondingly, three types of trichoid sensilla, types A, B, and C, on the antennae of male H. armigera could detect these compounds. The receptor OR13 responding to Z11-16∶Ald is expressed in the type-A trichoid sensillum, OR14b responding to Z9-14∶Ald is expressed in the type-B trichoid sensillum, and OR6 and OR16 responding to Z9-16∶Ald, Z9-14∶Ald, and Z11-16∶OH are expressed in the type-C trichoid sensillum. The expression sites and functions of the receptors are consistent with the electrophysiological characteristics of different types of trichoid sensilla. In addition, the results of calcium imaging showed that three macroglomeruli tune to these odors, among which the glomerulus of cumulus tunes to Z11-16∶Ald, the posterior dorsomedial glomerulus to Z9-16∶Ald, and the anterior dorsomedial glomerulus to Z9-14∶Ald, Z11-16∶Ac and Z11-16∶OH. These results revealed the mechanisms of pheromone reception in male H. armigera at the levels of sensillum, receptor and central nervous system. Based upon these studies, we think it is necessary to make further studies on the following aspects: (1) further identifying the function and location of the related sex pheromone receptors; (2) further studying the processing and integration of sex pheromone information in high brain center; (3) clarifying the influences and mechanisms of such environmental factors as host plant, photoperiod, temperature and humidity on the sex pheromone perception in H. armigera.

Key words: Helicoverpa armigera, sex pheromone, receptor, sensillum, antennal lobe; glomerulus