Alarm Pheromones of the Ant Atta Texana
Methyl-3-heptanone (0.59 μg/head) and 2-heptanone (0.14 μg/head) are the main volatile components of the mandibular glands of major workers. In the laboratory, worker ants detected and were attracted by 4-methyl-3-heptanone at a concentration of 5.7 x 10-13 g/cm3 (2.7 x 107 molecules/cm3). They were alarmed by a concentration of 5.7 x 10-12 g/cm3 (2.7 x 108 molecules/cm3). 2-Heptanone is less effective by a factor of 1000. In the field, low concentrations attract and alarm; high concentrations repel and alarm.