EFFECT OF LARVAL DENSITY ON WHOLE-BODY BIOGENIC-AMINE LEVELS OF TRIBOLIUM-FREEMANI HINTON

1. Various biogenic amines, their precursors and metabolites in gregar ious and solitary forms of the flour beetle Tribolium freemani Hinton larvae were measured using high-performance liquid chromatography coup led with electrochemical detection. 2. Octopamine was much more abunda nt than dopamine, serotonin, epinephrine, norepinephrine and related s ubstances, suggesting that octopamine may play much more important rol es in growth and behaviour of T. freemani than other biogenic amines a nd related substances. 3. Octopamine levels were higher in gregarious forms than solitary forms of T. freemani larvae, and the relation betw een octopamine content, hormone cycles and motility is discussed.