In this project, I used Taraxacum officinale (common dandelion) as focal plant and Poa pratensis (kentucky bluegrass) and Centaurea stoebe (spotted knapweed) as neighboring plants. Taraxacum officinale is a perennial herbaceous plant co-occurring with P. pratensis and C. stoebe in Eurasia. I furthermore worked with Melolontha melolontha (white grub) larva, which are highly polyphagous but prefer to feed on T. officinale. The project had three major scientific objectives: (1) Determine the impact of plant neighbor and neighbor attack on root metabolism of T. officinale and the performance of M. melolontha larvae, (2) Disentangle the chemical signals of neighbor recognition, below ground volatiles or root exudates, and (3) Identify chemical signals involved in neighbor recognition.
Basically, I have fully reached objective (1) and (2) and made significant progress towards three over last two years from March 1, 2016 to September 30, 2017. I found that neighboring plant significantly affected T. officinale root defenses, which in turn influenced the performance of M. melolontha larvae feeding on T. officinale. This associational effect was triggered by both root volatile and exudates released by neighboring plant. Terpenes were identified as major active singles. So far, one paper entitled “Neighbourhood effects determine plant-herbivore interactions below-ground” has been published in Journal of Ecology in 2017 and also presented as a poster in 16th Symposium on Insect-Plant Relationships in France, one manuscript is being under review in Functional Ecology, and some raw data is being processed.
