Do Lecythidaceae specialists (Coleoptera, Cerambycidae) shun fetid tree species?

Characteristic secondary metabolites are currently acknowledged to play a p ivotal role in the circumscription of a plant's insect fauna. A newly disco vered association between wood-boring longicorn beetles (Cerambycidae) and their host trees belonging to the Brazil nut family (Lecythidaceae) inspire d a yearlong rearing project in the lowland Neotropical rain forest of cent ral French Guiana. Branches severed from five species of Lecythidaceae yiel ded 1813 cerambycids belonging to 37 species. Two of the five tree species, Couratari stellata and Gustavia hexapetala, yielded impoverished complemen ts of cerambycids that included Large percentages of generalists. Both tree species are characterized by fetid odors. Wood samples collected from the malodorous C. stellata, as well as from two well-colonized species, Lecythi s poiteaui and Eschweilera coriacea, were analyzed for their volatile compo nents. Sulfur compounds accounted For almost 15 percent of the volatiles de tected From C. stellata, while they were at most minor components of the tw o well-colonized tree species. S-methylmethionine, isolated from a C. stell ata wood sample, appeared to be the major sulfur compound contributing to t he distinctive smell. We hypothesize that this foul odor is a deterrent to specialist cerambycids seeking oviposition sites.