S. Anton et Bs. Hansson, ANTENNAL LOBE INTERNEURONS IN THE DESERT LOCUST SCHISTOCERCA-GREGARIA(FORSKAL) - PROCESSING OF AGGREGATION PHEROMONES IN ADULT MALES AND FEMALES, Journal of comparative neurology, 370(1), 1996, pp. 85-96
Physiological and morphological characteristics of antennal lobe inter
neurons in male and female Schistocerca gregaria were studied by using
intracellular recording and staining techniques. For the first time,
the responses of projection neurons to behaviourally active and potent
ial aggregation pheromone compounds and plant odour compounds were rec
orded in young adult locusts. Excitatory, inhibitory, or combined exci
tatory/inhibitory responses to the presented odours were detected. The
stained neurons had their cell bodies in the frontal cell group, arbo
rized in 10 to 25 glomeruli at equal distances from the central fibre
core, and sent their axons to the calyces of the mushroom body and to
the lateral protocerebrum. The projection neurons responded to the set
of different stimuli with varying specificity. In females, more neuro
ns responded specifically to single plant or aggregation pheromone com
pounds than in males, where more generalist responses were found. ''Bl
end specialist'' neurons, responding only to mixtures of behaviourally
active aggregation pheromone compounds, but not to the single compoun
ds, were present in both males and females. Most neurons responded to
the behaviourally active aggregation pheromone mixtures and to single
compounds present in these mixtures, as well as to plant odours. Fewer
neurons responded to the potential aggregation pheromone compounds te
sted. In several experiments, two spike sizes in the recording were co
rrelated with two stained neurons in the antennal lobe, suggesting ele
ctrical coupling of the neurons. No response to any of the stimuli was
found in antennal lobe interneurons in old adults. The morphological
and physiological features of the projection neurons in S. gregaria ar
e compared with projection neuron characteristics in other insects. (C
) 1996 Wiley-Liss, Inc.