Proctolin affects gut functions in lepidopteran larvae

摘要: We examined if the pentapeptide proctolin, a well-investigated myotropic neutrotrasmitter/neuromodulator for which possible role in insect control has been suggested, affected gastrointestinal function lepidopteran larvae. verified model species Bombyx mori (Lepidoptera, Bombicidae) visceral muscles of larval gut expressed receptors peptide, by monitoring spontaneous contractions hindgut absence or presence proctolin. The frequency peristaltic increased only at very high concentration suggesting that proctolin could effectively bind with low affinity to non-specific receptors. outcome on fitness increasing doses orally administered fourth instar larvae were investigated recording standard nutritional indices. A significant decrease Efficiency Conversion Ingested and Digested food body substance concomitant reduction Relative Growth Rate (RGR) was observed lowest dose tested (0.18 mg/g larva). amount peptide appeared critical, because 10-fold higher abolished negative effect RGR stimulation feeding behaviour, possibly as result activation compensatory mechanisms. similar also polyphagous pest Spodoptera littoralis Noctuidae).