Occurrence of a prothoracicotropic hormone-like peptide in the developing nervous system of the honey bee (Apis mellifera L)

Abstract

An antibody generated against prothoracicotropic hormone (PTTH) of the silkworm Bombyx mori reacted with distinct sets of cells in the central nervous system and also in the retrocerebral complex of Apis mellifera larvae and pupae. Neurons expressing a Bombyx-PTTH-like peptide were first detected in the spinning stage of the last larval instar. Five distinct clusters of brain neurons comprising a total of 20-24 neurons were stained in this larval stage, in addition to a pair of somata located in the labial neuromere and in the first thoracic ganglion. With progressing metamorphosis this pattern changed. In white-eyed pupal brains only two neurons in the dorsal protocerebrum continued to express a PTTH-like peptide, whereas in the suboesophageal ganglion each neuromere now contained a pair of immunoreactive neurons. No axonal PTTH immunoreactivity was detected.