Hennessy, Louise MPopay, Alison JGlare, TravisFinch, Sarah CCave, Vanessa MRostás, Michael2021-05-182021-04-212021-04-212021-04-031612-4758YC9LY (isidoc)https://hdl.handle.net/10182/13805Argentine stem weevil adults (ASW, Listronotus bonariensis) feed on the leaves of agricultural grasses and their larvae mine the pseudostem, causing extensive damage that can result in plant death. Plants emit volatiles that serve as signals to host-searching insects and these odours can be altered by both herbivory and fungal endophyte-infection. This study investigated whether ASW adults utilise olfaction to identify their host plants, perennial ryegrass (Lolium perenne), and if conspecific herbivory or the presence of Epichloë festucae var. lolii fungal endophytes (strain wild-type or AR1) influenced such responses. Results from olfactometer bioassays established that ASW adults were able to utilise their olfactory response to orient towards volatiles released by perennial ryegrass and further, the weevils displayed a preference for plants previously damaged by conspecific weevils. However, there was no evidence that weevils had the ability to distinguish between endophyte-infected and endophyte-free plants using olfaction alone. Using a push–pull extraction technique, thirteen volatile compounds were identified in the blend released by perennial ryegrass. Endophyte and herbivory were found to alter these volatile compounds and quantities emitted by this forage grass. This study suggests that despite observing differences in the plant volatile blend, ASW do not perceive endophyte (wild-type and AR1) using olfaction alone and must rely on other cues, e.g. contact chemoreception or post-ingestional malaise, to detect the presence of a bioactive endophyte in an otherwise acceptable host plant.15 pagesPrint-Electronicen© 2021, The Author(s).Listronotus bonariensisLolium perenneEpichloëherbivore included plant volatileshost choicevolatilesHumansAdultGraves OphthalmopathyJournal Article10.1007/s10340-021-01375-21612-4766ANZSRC::300409 Crop and pasture protection (incl. pests, diseases and weeds)ANZSRC::410302 Biological controlANZSRC::410202 Biosecurity science and invasive species ecologyANZSRC::310805 Plant pathologyANZSRC::3109 Zoologyhttps://creativecommons.org/licenses/by/4.0/Attribution