Review of the chemical ecology of homoterpenes in arthropod–plant interactions

The homoterpenes 4,8-dimethyl-1,3,7-nonatriene (DMNT) and 4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT) are volatile products of plant metabolism reported from diverse taxa multiple tissues. As such, they have a range potential ecological functions. Here, we review the key literature to assess evidence for roles in contrasting plant–arthropod interactions. TMTT, DMNT especially, been as sometimes dominant constituents floral scents angiosperm ranging primitive Magnoliales more advanced, taxonomic orders economic significance such Fabales Sapindales. Although all producing TMTT entomophilous (‘insect pollinated’), experimental an assumed role these pollinator attraction is limited. Representing trade-off, some cases, shown act kairomones, attracting herbivores. Additionally, both released by foliage response arthropod feeding, mechanical damage simulating or even egg deposition. Evidence functional herbivore-induced (HIPV) blends comes wide orders, including anemophilous (‘wind pollinated’) taxa, well gymnosperms. We conclude considering how function community-level interactions highlighting research priorities that will reveal plants avoid trade-offs functions release homoterpene production might be exploited develop improved crop varieties.