Behavioral assessment of lines of Drosophila melanogaster selected for central excitation.

Selected lines of Drosophila melanogaster, bred for high and low levels of central excitatory state (CES), were used in experiments to assess the effects of artificial selection on CES expression and to identify other correlated traits that may have become manifest during selection. Results indicate that the selected lines display (a) different levels of CES, (b) differences in water responsiveness (possibly due to differences in dehydration rates), (c) no water-induced CES, and (d) no significant amounts of sensitization or conditioning. Also, CES in the high line is not dissipated by subsequent posttest stimulations. Comparing the characteristics of CES in Drosophila and in Phormia regina reveals significant species differences. The relevance to earlier P. regina work with respect to CES and conditioning is discussed.