Alarm substances of the stingless bee,Trigona silvestriana

2-Nonanol, 2-heptanol, octyl decanoate, and octyl octanoate were identified from the heads ofTrigona silvestriana workers. When presented at the nest, 2-nonanol, 2-heptanol, and the mixture of the four compounds elicited angular flights, landing, and buzzing of guard bees. Octyl octanoate elicited a weaker response. No response was given to octyl decanoate, to the ether solvent, or to the control volatile, vanillin.