Insect neuropeptides are involved in a variety of host functions, including energy metabolism, osmoregulation and mating behavior. The study on insect neuroendocrinology has rapidly grown and there are roughly 50 identified insect neuropeptide families.

Neuropeptides are produced from larger precursor proteins which are known as prepropeptides. Prepropeptides comprise of a signal peptide (which directs the protein to the secretory pathway), progenitors of mature peptides (the biologically-active peptides), spacer peptides (peptide fragments with no known biological function and non-conserved sequences) and cleavage sites (monobasic and dibasic). Each precursor can give rise to one or more mature neuropeptides or peptide hormones. The number of mature peptides produced from a given precursor can vary from one insect species to another. These can either be (1) a set of very similar peptides with partly conserved sequences and thus similar receptor activation properties (such as tachykinin-related peptides, AstBs and FMRFamides), or (2) in some cases peptides with distinct sequences and functions. Examples of precursors containing peptides with distinct sequences and functions (bind distinct receptors) are those of CAPA/Pyrokinin, NPLP1 and vasopressin (see Stafflinger et al., 2008; Nässel and Winther 2010). There are also examples of peptides with similar sequences being produced by paralogs and splice variants. Insulin-like peptides are encoded by up to 38 paralogous genes in the moth Bombyx mori and 8 genes in Drosophila (see Mizoguchi and Okamoto, 2013). The orcokinin gene in insects produces two different neuropeptide precursors by alternative splicing: orcokinin A and orcokinin B (Jiang et al, 2015). A typical prepropeptide and its biosynthesis and processing is shown in the diagram.

All information on the neuropeptides (More Info) provided by Dr. Meet Zandawala and Prof. Dr. Dick R. Nässel from the Department of Zoology, Stockholm University, Stockholm, Sweden

Below is a list of insect neuropeptide families. Where applicable, their synonyms are also listed. To find out more about each insect neuropeptide, please click on the ‘More Info’ button.