title: Parasitic wasp females are attracted to blends of host-induced plant volatiles: do qualitative and quantitative differences in the blend matter?
abstract: Naïve Cotesia vestalis wasps, parasitoids of diamondback moth (DBM) larvae, are attracted to a synthetic blend (Blend A) of host-induced plant volatiles composed of sabinene, n-heptanal, α-pinene, and ( Z)-3-hexenyl acetate, in a ratio of 1.8:1.3:2.0:3.0. We studied whether qualitative (adding ( R)-limonene: Blend B) or quantitative changes (changing ratios: Blend C) to Blend A affected the olfactory response of C. vestalis in the background of intact komatsuna plant volatiles. Naïve wasps showed equal preference to Blends A and B and Blends A and C in two-choice tests. Wasps with oviposition experience in the presence of Blend B preferred Blend B over Blend A, while wasps that had oviposited without a volatile blend showed no preference between the two. Likewise, wasps that had starvation experience in the presence of Blend B preferred Blend A over Blend B, while wasps that had starved without a volatile blend showed no preference between the two. Wasps that had oviposition experience either with or without Blend A showed equal preferences between Blends C and A. However, wasps that had starvation experience in the presence of Blend A preferred Blend C over Blend A, while those that starved without a volatile blend showed equal preferences between the two. By manipulating quality and quantity of the synthetic attractants, we showed to what extent C. vestalis could discriminate/learn slight differences between blends that were all, in principle, attractive.
authors.affiliation: Center for Ecological Research, Kyoto University, Otsu, Shiga, 520-2113, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Uefune
authors.affiliation: Center for Ecological Research, Kyoto University, Otsu, Shiga, 520-2113, Japan ; National Institute for Agro-Environmental Science (NIAES), Tsukuba, Ibaraki, 305-8604, Japan.
authors.forename: Soichi
authors.initials: S
authors.lastname: Kugimiya
authors.affiliation: Center for Ecological Research, Kyoto University, Otsu, Shiga, 520-2113, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Ozawa
authors.affiliation: Center for Ecological Research, Kyoto University, Otsu, Shiga, 520-2113, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Takabayashi