Quantification of cockroach allatostatin-like peptide and its myotropic effects in males of the earwig Euborellia annulipes

A monoclonal antibody to allatostatin I of the cockroach Diploptera punctat a was used to establish a competitive enzyme-linked immunosorbent assay for quantification of allatostatin-like peptides in the hindgut of the adult m ale earwig, Euborellia annulipes. Hindguts of 0-day males contained signifi cantly more allatostatin-positive material than those of 8-day males fed on catfood. However, males starved for the first 8 days of adult life had sig nificantly higher levels of allatostatin-positive material than those of ei ther 0-day or of 8-day fed males. Hindguts from 0-day old males exhibited lower spontaneous motility in vitro than those from 8-day males. Hindguts from males at both ages responded to allostatin with reversible, dosage-dependent decreases in hindgut motility , and responded to proctolin with reversible, dosage-dependent increases in hindgut motility. When both allatostatin and proctolin were applied to hin dgut preparations simultaneously and in equal concentrations, the response varied with the stage of the male. Starvation enhanced hindgut motility and abolished the response to allatostatin, but not to proctolin. These results indicate the presence of material similar to cockroach allato statins in male earwigs, and that the levels change with age and physiologi cal stage. Furthermore, such peptides may indeed be regulatory neuropeptide s and could modulate hindgut contraction. There was an increase in sensitiv ity to exogenous allatostatin in the hindgut during development from day 0 to day 8 in feeding males, but a loss in sensitivity in response to starvat ion; sensitivity to exogenous proctolin also increased with age, but such r esponsiveness was not diminished by starvation.