3.6 Behavioral bioassays
Male ECB moths responded with approach and landing to 50 μg of the
pheromone blend corresponding to the Z -race (Figure 5B). As
BioPhe contains just 7.2% Z 11-14:OAc, a 700 μg stimulus of
BioPhe was tested in lab bioassays (containing approx. 50 μgZ 11-14:OAc). Significantly fewer source-oriented approaches and
fewer landings were observed compared to the response elicited by the
optimal Z-race pheromone, indicating the presence of compound(s)
interfering with the insects’ anticipated behavior.
In the BioPhe sample 14:OAc comprises almost 50% of the total amount.
To emulate a BioPhe sample, 350 μg 14:OAc were added to the 50 μg
pheromone blend (97:3). In this case, males scored significantly lower
in both approach and landing. This is an indication that 14:OAc at this
dose interferes with the precopulatory behavior of O. nubilalis.
Similarly, when 4.5 μg of Z 9-16:OAc was added to the 50 μg
pheromone blend (97:3), significantly fewer landings were recorded, but
the frequency of approaches did not differ significantly from what was
observed in response to the native pheromone .