High level expression of "male specific" pheromone binding proteins (PBPs)in the antennae of female noctuiid moths

Pheromone Binding Proteins (PBPs) are one branch of a multigene family of l epidopteran Odorant Binding Proteins (OBPs) that are known for their relati vely high levels of expression in male antennae. However, PBP expression ha s been observed at low levels in female antennae of the Saturniidae, Bombyc idae and Lymantriidae, and at relatively high levels in members of the Noct uiidae. The function of female PBP expression is unclear, as female lepidop tera are consistently noted for their failure to respond physiologically or behaviorally to sex-pheromone. In this study, the sexual dimorphism of PBP expression was examined in the noctuiid moths Helicoverpa tea, Heliothis v irescens and Spodoptera frugiperda. A PBP cDNA clone was isolated from fema le H. zea, PBP-Hzea,. Northern blot analysis indicated relatively high leve ls of PBP-Hzea, expression in both male and female antennae, though females consistently expressed about 50% that of males. Western blot analysis of m ale and female PBP expression supported these relative differences. Immunoc ytochemical analysis indicates discrete expression localized beneath olfact ory sensilla of both male and female antennae. These results suggest female noctuiids possess the biochemistry to detect at least components of their sex-pheromone. Alternatively, these results may suggest that PBPs have a mo re general function in noctuiids, possibly reflecting behavioral and life h istory differences that distinguish this the Noctuiidae from other Lepidopt eran families. (C) 2000 Elsevier Science Ltd. All rights reserved.