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The effects of different blend ratios and temperature on the active space of the Oriental fruit moth sex pheromone
Author(s) -
LINN CHARLES,
ROELOFS WENDELL
Publication year - 1991
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.1991.tb00558.x
Subject(s) - biology , zoology , pheromone , horticulture , botany
The wing‐fanning activation response of male Oriental fruit moths (OFM), Grapholita molesta (Busck), in the field to the three‐component pheromone containing the female‐produced ratio of components (Z8‐12:OAc + 6% E8‐12:OAc + 3% Z8‐12:OH) was compared with the response to blends containing 2,10 and 20% E with 3% OH, and the 6% E blend containing 30 and 100% OH. Comparisons were made over three temperature ranges: 15–17, 20–21 and 26–28 o C. Both the maximum response distance and male response specificity were significantly altered by changes in odour quality as well as temperature. For blends containing different Z/E ratios the maximum response distance increased significantly with temperature. Response specificity was most pronounced at the 20–21 o C range, with males displaying a lower threshold for the natural 6% E ratio, evidenced by the fact that fewer males responded and at closer distances to the source with off‐ratios. At 26–28 o C response specificity for the Z/E ratios was much reduced, primarily due to more males activating to off‐ratios. With blends containing different proportions of Z8‐12:OH in the 6% E blend, increasing temperature increased the maximum response distance for all treatments, but in addition increasing the proportion of OH alone from 3% to 30% significantly increased the maximum response distance over the three temperature ranges tested. This increase occurred without affecting the proportion of responders or the distribution of response distances around the mean value. However, with 100% OH added to the blend, whereas male response was high at 20–21 o C, the distribution of response distances was significantly more variable than with 3% or 30%, and male response was eliminated or very low at 15–17 o C and 26–28 o C. Our results support previous studies showing that peak response levels in this species are dependent on male perception of the natural blend of components, and that males have a high degree of specificity for the qualitative properties of the pheromone. However, the present results also extend those of previous flight tunnel tests in which response specificity was most pronounced in the upwind flight phase of the sequence, by showing that male OFM also display a