ASPECTS OF ORIENTATION BEHAVIOR IN THE AMBROSIA BEETLE TRYPODENDRON LINEATUM (OLIVIER)

Abstract

Post-diapause, reproductively mature adults of Trypodendron lineatum display various kinds, patterns, and levels of activity in respect to light, temperature, odor, air flow, and gravity. This activity is influenced by recent flight-history of the beetles, the nature of the factor primarily being examined, its manner of presentation, and its context among the other factors. Photic stimuli are important determinants of spontaneous flight and of olfactory responses to host-tree odor. In turn, the photic response alone and its domination over the olfactory response are modified by temperature, and by the recent flight-history of the individual. Host attractant suppresses photic orientation of the flown beetle, and causes retention in a field of host attractant-bearing air current. The behavior studies reveal that the healthy, living host tree contains neither olfactory attractants nor repellents, but a felled and dying tree of appropriate species contains a primary olfactory attractant for both male and female beetles. The studies provide the foundation for 2 basically new techniques using the beetles as bioassay instruments in evaluating odors of significance to them.