Neuropeptide profiling of Bombus terrestris (Hymenoptera, Apidae) and comparative analysis across hymenopteran species

Bombus terrestris is a Palearctic bumblebee species known for its excellent pollination activity. Due to its versatility, it has recently become a preferred species for greenhouse pollination worldwide. This species is also frequently used in experiments aimed at studying both the behavioral and physiological aspects of Hymenoptera. Key molecules in these research fields are neuropeptides, which regulate nearly all physiological processes in metazoans. In the current study, initial sequence identification and mass spectrometry analyses were conducted to identify processed neuropeptides in B. terrestris workers. The list of neuropeptide precursors was updated, and their distribution across the CNS was investigated using a combination of mass spectrometry and immunohistochemistry. Specific features of the B. terrestris peptidome were identified as well as those shared with other Apidae. In B. terrestris, some peptidergic systems were not identified, some of which are also absent in other Hymenoptera, while few neuropeptides, such as sulfakinin and corazonin, show derived sequences. Moreover, using mass spectrometry, for the first time, were identified neuropeptides from the abdominal transverse nerve neurohemal organ of Apidae and the presence of elevenin in the thoracic perisympathetic organs of B. terrestris was also reported. Additionally, a comparison of the B. terrestris capa gene structure with other hymenopteran species revealed a deletion in one exon shared by Apidae + Megachilidae, supporting the monophyly of long-tongued bees.