Figure 1. Pheromone perception in Drosophila courtship.

(a) Proposed model for how pheromonal cues guide male behavior at different spatial ranges. Note that neuron names are color-coded to match the illustrations in (b) and (c).

(b) Hypothetical wiring diagram from chemosensory inputs to descending motor output. Darker arrows suggest strong experimental evidence for synaptic connections and the direction of information flow, whereas lighter arrows suggest probable connections based on neuroanatomical data, i.e. physical overlap (see (c)). The putative connection from mAL to pMP4/P1 may be inhibitory[26], suggesting that the wiring diagram above is incomplete, as pMP4/P1 neurons must get excitatory input from somewhere else.

(c) 3D renderings of neurons involved in pheromone processing (left), sensory integration (middle), and motor control (right). Black arrowheads illustrate sensory input (left) or motor output (right), respectively.

Fly cartoon images adapted with permission from Sokolowski, Nature Reviews Genetics 2:879-890 (2001).