P1.126  Tuesday, Jan. 4  Behavioral and physiological studies of sex pheromonal olfaction in interspecific antennal imaginal disc transplants LEE, S.-G.*; POOLE, K.; LINN JR., C.E.; VICKERS, N.J.; University of Utah; Cornell University; Cornell University; University of Utah s.g.lee@utah.edu

The closely-related moth species Heliothis virescens and Heliothis subflexa have sympatric distributions in North America. Both species utilize the same chemical substance (Z11-16:Ald) as their major pheromone component. The four pheromone-related olfactory glomeruli (macroglomerular complex, MGC) in the male antennal lobes of both species show structural similarity. However, three smaller satellite glomeruli are heterologous in their functions, unlike the large cumulus which is involved in processing Z11-16:Ald in both species. Each of three satellite MGC glomeruli is the synaptic target for three types of olfactory receptor neurons (ORNs) that are responsive to minor pheromone components or behavioral antagonists. The presence of these three types of ORNs is critical for accurate olfactory discrimination and appropriate behavioral responses. The heterogeneity in behavioral response across species to these minor pheromone components is a consequence of different processing systems in their higher brain centers. Comparative studies of the connections that form between the ORNs and second order olfactory projection neurons in the two species are therefore important in understanding how two species can process the same odor information in different ways. Our comparative studies make use of transplants of male antennal imaginal discs between H. virescens and H. subflexa. Behavioral, physiological, and morphological examination of interspecific transplants revealed that there is some variability in the glomerular targets of specific ORNs. Despite this variation, activation of specific central olfactory pathways was sufficient for attractive behavioral responses to occur.