Sexual dimorphism in the olfactory orientation of adult Cydia pomonella in response to α‐farnesene

Abstract

The role of host plant‐derived volatile substances on the behaviour of adult codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae) is poorly understood. We tested the response of females and males to a range of α‐farnesene dosages. Natural α‐farnesene from apples contains the E,E and Z,E isomers in varying proportions. No difference in the response of C. pomonella to preparations containing two different proportions of the E,E and Z,E isomers was noted (77:20.7 or 1.2:84.7% E,E and Z,E isomers respectively), indicating a similar bioactivity of E,E and Z,E α‐farnesene on codling moth. A marked sexual dimorphism was found to increasing dosages of α‐farnesene. Females were attracted to low dosages (starting from 63.4 ng) and repelled by high dosages (ending at 12 688 ng). The dose response over this concentration range was linear with a negative slope. Both mated and virgin females responded similarly in kind but differently in degree, both attraction and repellency being more pronounced in mated females. Males were neither attracted nor repelled over a large dose range (63.4 to 12 688 ng) except the highest rate which was attractive. This indicates a stronger dependency of females on plant‐derived volatiles.

Electrophysiological responses of eucalyptus brown looper Thyrinteina arnobia to essential oils of seven Eucalyptus species

“…33 (E,E)-α-Farnesene, the main constituent of apple odor, stimulates oviposition and attracts neonate larvae and adult females of Cydia pomonella at short range. 34 This compound is also found in many other plants. Linalool acted electrophysiologically on C. pomonella female antennae.…”

Three-dimensional antennal lobe atlas of male and female moths, Lobesia botrana (Lepidoptera: Tortricidae) and glomerular representation of plant volatiles in females

“…The majority of these PNs arborised in the anterior central part of the AL. α-farnesene has been shown to be a potent attractant in the codling moth, Cydia pomonella, another tortricid moth (Sutherland and Hutchins, 1972;Hern and Dorn, 1999;Bengtsson et al, 2001;Coracini et al, 2004). Our previous study showed that AL neurons in both males and females of L. botrana responded to α-farnesene (Masante-Roca et al, 2002).…”

Coding and interaction of sex pheromone and plant volatile signals in the antennal lobe of the codling moth Cydia pomonella

“…In contrast to males, the sesquiterpenes (E,E)-a-farnesene and (E)-bfarnesene elicited strong responses in female AL neurons (Tables1, 2). (E,E)-a-farnesene, a main component of apple headspace , is detected by very sensitive ORNs (Bäckman et al, 2000) and has been shown to contribute to the attraction of females (Hern and Dorn, 1999) and males, in combination with (E)-b-farnesene .…”