Analysis of anal droplets of the western flower thrips Frankliniella occidentalis.

Larvae of the western flower thrips Frankliniella occidentalis are known to produce an anal droplet containing decyl acetate (10Ac) and dodecyl acetate (12Ac), which act as an alarm pheromone. Analysis by GC showed that the combined mass of 10Ac and 12Ac per droplet increased with age of second instars from 2 ng to 18 ng, while the mass ratio of 10Ac:12Ac increased from 0.4:1 to 1.