Figure 2

Differences in identified neurons and neuronal circuits between solitarious and gregarious locusts. (A) The receptive field organization of the visual looming detector neuron DCMD across a visual hemisphere in solitary and gregarious locusts is shown. Maximum spike rates of DCMD are colour-coded. Data from [23]. (B) The DCMD of solitarious locusts (blue) shows more pronounced habituation to a visual stimulus repeated at 45-second intervals than that in gregarious locusts (red). (C) Compound EPSP response in FETi (upper trace) evoked by activity in the DCMD (middle trace) following exposure to a looming stimulus (angular subtense to 90°, lower trace) is shown. (D) EPSPs evoked by individual DCMD spikes in FETi are twice the amplitude in solitarious locusts (blue) compared to those in gregarious locusts (red). Data for (B) through (D) are from [24]. (E) Individual frames from walking sequences of solitarious and gregarious locusts are shown. (F) Histograms of excursions of the hind femorotibial joint during a walking step by solitarious and gregarious locusts are shown. (G) SETi shows tonic activity and a consistently greater response during an imposed resistance reflex of the hind femorotibial joint in solitarious locusts compared to gregarious locusts. Data for (E) through (G) are from [28].