The Molecular Genetics of Olfaction and Other Aspects of Host Preference Selection Behaviors in Anopheline Mosquitoes
Laurence J. Zwiebel
Department of Biology
6260A BSB/MRB III
The major focus of the my group’s research is the isolation and characterization of genes that are involved in critical behaviors of economically important insects such as disease vectors and agricultural pests. One example of such a behavior that we are investigating is host (i.e. blood-meal source) seeking/selection in several Anopheline mosquitoes comprising the principal mosquito vectors for malaria and other diseases that are responsible for over 3 million deaths annually. In this context, we are studing the genes encodijg the molecular components of olfaction (smell) in the vector mosquito An. gambiae s.s. because olfaction is the dominant sensory input for host preference behaviors in mosquitoes and other insects. Since these behaviors make a critical contribution to the vectorial capacity of this mosquito as well as playing similar roles in the overall impact of many other insects of economic and medical importance, an analysis of the molecular basis for olfactory discrimination in this system is of fundamental significance.
In addition to continuing these studies we are engaged in several other projects in collaboration with groups at Notre Dame University and the Max-Planck Institut fur Verhaltenphysiologie in Seewiesen, Germany. These include a fine structure analysis of the olfactory apparatus of An. gambiae s.s. as well as an electrophysiological study of olfaction in this system. Furthermore, a molecular characterization of genes which potentially mediate aspects of the marked preference for human blood meals (anthropophily) characteristic of An. gambiae s.s. is being carried out This particular behavioral preference is largely responsible for making this mosquito such an potent vector for malaria. In contrast, a strong preference for bovine blood meals (zoophily) has been observed in a sibling species An. quadriannulatus and is thought to be responsible for is non-vector status. We hope that a molecular comparison of olfactory genes and central processing pathways between these mosquito species, a vector and its non-vector sibling, will lead to a better understanding of the nature of these behaviors and the role that they play in malaria transmission.