tobacco budworm
not annotated - annotated - LINNAEUS only
20946532
Functional characterization of pheromone receptors in the tobacco budworm Heliothis virescens.
Functional analyses of candidate Heliothis virescens pheromone odorant receptors (HvORs) were conducted using heterologous expression in Xenopus oocytes. HvOR6 was found to be highly tuned to Z9-14:Ald, while HvOR13, HvOR14 and HvOR16 showed specificity for Z11-16:Ald, Z11-16:OAc and Z11-16:OH, respectively. HvOR15, which had been considered a candidate receptor for Z9-14:Ald did not respond to any of the pheromone compounds tested, nor to 50 other general odorants. Thus, while HvOR15 is specifically expressed in H. virescens male antennae, its role in pheromone reception remains unknown. Based on our results and previous research we can now assign pheromone receptors in H. virescens males to each of the critical H. virescens agonistic pheromone compounds and two antagonistic compounds produced by heterospecific females.
21521143
Post-egression host tissue feeding is another strategy of host regulation by the Koinobiont wasp, Toxoneuron nigriceps.
Koinobiont wasps start their lives as hemolymph feeders inside the host body, but before they egress from the host many become tissue predators. One species, the endoparasitoid Toxoneuron nigriceps Viereck (Hymenoptera: Braconidae), exhibits the unusual behavior of egressing before initiating tissue predation. After egression from the host, it reinserts its head into the host body to begin tissue feeding. These third instar T. nigriceps larvae show a significant increase in body size and mass after post-egression feeding. Through this project the importance of post-egression feeding in the development of T. nigriceps in its host the tobacco budworm, Heliothis virescens Fabricius (Lepidoptera: Noctuidae), has been evaluated. The study was conducted by preventing the egressed third instar T. nigriceps larvae from feeding on host tissue and observing whether they could undergo further development. Though some of the larvae that were prevented from post-egression feeding did undergo cocoon formation, pupation, and adult emergence they were inferior in terms of size, body mass, and survival to those that developed from larvae allowed to feeding after egression. Hence, it is concluded that post-egression host tissue feeding is essential for the normal development of T. nigriceps, as the prevention of feeding resulted in significantly lighter and smaller larvae, cocoons, and adults as well as deformed adults and reduced adult survival. Post-egression feeding as a host regulatory strategy is discussed.