Artificial selection in pheromone permeated air increases mating ability of the European grape vine moth Lobesia botrana (Lep., Tortricidae)

The existence of L. botrana genotypes more suitable to mating in synthetic pheromone permeated air in olfactometer was investigated by artificial selection through two consecutive generations. The major compound of the female pheromone blend (7E, 9Z)‐7, 9‐dodecadienyl acetate 7E, 9Z DDA was used, the only one commercialized at present both for monitoring and for mating disruption. The adults mated in a mating disruption atmosphere in the parental generation (G1) were reared separately to make up the selected filial generation (G2). Trial was carried out at the doses of 0 (control), 0.5 and 1 μg of 7E, 9Z DDA. In G1 83.33% (50/60 pairs), 18.87% (50/265) and 8.62% (31/360) mated respectively. In the selected generation (G2) 76.67% (46/60), 20.91% (69/330) and 14.38% (64/445) mated respectively. Thus, control mating percentages in both generations were similar. Nevertheless, after selection the increase in mating was significant at 1 μg dose (G = 6.53; d.f. = 1; P < 0.05) but not at 0.5 μg (G = 0.38; d.f. = 1; P > 0.05). On the other hand, selection for increasing mating ability in sex pheromone permeated air at the doses tested, was not linked with a decrease in the dusk time elapsed before mating (mean: 24–30 min). With regard to the controls without pheromone (mean: 10–12 min), matings were significantly delayed (F(5,04) = 18.52; P < 0.01). The differences in response to selection between pheromone doses show the possible effect of the genetic homeostasis. These preliminary results suggest a genetic basis for mating ability and are a complementary hypothesis to explain the lack of an absolute efficiency in control by mating disruption. Finally, the possible factors that could interact and counteract the studied selection pressure are discussed, since resistance to the mating disruption method has not been observed at this time in field conditions.