Activation of pC1 and pC2l neurons induces courtship in males.

<p>Male flies that carry <i>dTrpA1</i>-expressing MARCM clones were tested for the occurrence of courtship behavior in response to temperature increases, followed by immunohistochemical identification of neurons that were activated in the behavioral assays. We judged that a male responded to a temperature increase by courtship behavior (“Responder-C”) only when it vibrated its wings, while displaying any additional courtship actions, i.e., licking, tapping, and abdominal bending for copulation, and excluded those flies that exhibited wing displays alone without any additional element of courtship behavior, from the count of males positive for courtship responses. (<b>A</b>) Courtship behavior induced by a temperature increase to 35°C in a male carrying MARCM clones expressing dTrpA1. Note that the male is vibrating a wing while licking by extending his proboscis. (<b>B</b>) Labeling pattern of GFP expression in MARCM males. Each vertical column represents the scores of a single fly. Neuronal classes in the brain indicated in the left-hand column are described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126445#pone.0126445.g003" target="_blank">Fig 3B</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126445#pone.0126445.s001" target="_blank">S1 Fig</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126445#pone.0126445.s004" target="_blank">S1 Table</a> and those in the VNC are described in Ref. 19. § in B indicates that the images shown in Fig 7A, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126445#pone.0126445.s003" target="_blank">S3G</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126445#pone.0126445.s003" target="_blank">S3H</a> Fig, and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126445#pone.0126445.s016" target="_blank">S10 Movie</a> are of this fly. (<b>C</b>) The incidence of GFP-labeling of the indicated neural cluster (signifying dTrpA1 expression) was compared between the Responder-C (n = 51) and the rest of the tested flies (non-Responder, n = 114). GFP-labeling, and thus dTrpA1-mediated activation of pC1 and pC2l but none of the other clusters, was significantly correlated with the occurrence of courtship behavior in mosaic males. **** p < 0.0001, by Fisher’s exact probability test.