Epsilon Archive for Student Projects

Abstract

Plants constitutively emit volatile organic compounds (VOCs) affecting their surroundings. Under
attack by herbivores, plants emit additional distinct volatile compounds, so called herbivore induced
plant volatiles(HIPVs), that may act as indirect defense by attracting natural enemies of the
herbivore. Hoverflies (Diptera: Syrphidae) play a crucial role in biological pest control by preying
on aphids. Gravid females using visual and chemical cues—including aphid stress secretions and
HIPVs—to locate suitable oviposition sites. We investigate the attraction of Eupeodes corollae to
VOCs from aphid-infested radish plants to better understand the semiochemicals involved in natural
enemy attraction. E.corollae (Syrphidae) showed flight attraction towards a stream of headspace
volatiles directly injected into a wind tunnel, but not towards headspace samples that were dissolved
and vaporized in organic solvents. Headspace volatiles in organic solvent did not induce
oviposition, suggesting that the lack of behavioral response towards headspace samples was due to
the absence or wrong ratio of behavioral active chemicals, or a negative effect of the solvent.