Table 1.

Chemical compounds found in the head contents

Peak #	Compound	Ret. Index	Relative abundance [%]
1	Acetic acid	702	0.94
2	4-Methyl-3-hexanone	845	0.72
3	4-Methyl-3-heptanone	940	80.08
4	4-Methyl-3-heptanol	973	16.28
5	Undecane	1105	0.68
6	Nonanal	1111	0.87
7	Decanal	1213	0.43

Chemical compounds in bold were tested as alarm pheromones. Five heads were pooled per sample run in the GC–MS coupled to a thermodesorption unit as shown in Fig. 2