Figure 5.

Schematic representation of the proposed evolutionary history of the MDHns. In this representation, the MDHns originally projected from the mesothoracic neuromere (MsN, blue) to the sub-oesophageal zone and antennal mechanosensory and motor centre (AMMC/SEZ, lavender). In the last common ancestor of the Lepidoptera and Trichoptera, the MDHns were co-opted (1; Dashed MDHn branches) to innervate the antennal lobes (ALs, magenta). The innervation of the ALs was lost in the butterflies (2), but maintained in macrolepidoteran moths.