TY - JOUR TI - Discovery of methylfarnesoate as the annelid brain hormone reveals an ancient role of sesquiterpenoids in reproduction AU - Schenk, Sven AU - Krauditsch, Christian AU - Frühauf, Peter AU - Gerner, Christopher AU - Raible, Florian A2 - Falkowski, Paul G VL - 5 PY - 2016 DA - 2016/11/29 SP - e17126 C1 - eLife 2016;5:e17126 DO - 10.7554/eLife.17126 UR - https://doi.org/10.7554/eLife.17126 AB - Animals require molecular signals to determine when to divert resources from somatic functions to reproduction. This decision is vital in animals that reproduce in an all-or-nothing mode, such as bristle worms: females committed to reproduction spend roughly half their body mass for yolk and egg production; following mass spawning, the parents die. An enigmatic brain hormone activity suppresses reproduction. We now identify this hormone as the sesquiterpenoid methylfarnesoate. Methylfarnesoate suppresses transcript levels of the yolk precursor Vitellogenin both in cell culture and in vivo, directly inhibiting a central energy–costly step of reproductive maturation. We reveal that contrary to common assumptions, sesquiterpenoids are ancient animal hormones present in marine and terrestrial lophotrochozoans. In turn, insecticides targeting this pathway suppress vitellogenesis in cultured worm cells. These findings challenge current views of animal hormone evolution, and indicate that non-target species and marine ecosystems are susceptible to commonly used insect larvicides. KW - hormone KW - evolution KW - reproduction KW - vitellogenin KW - insecticides JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -