Floral Visits of Cordyla murina (Mycetophilidae) and Other Dipterans to Asarum asaroides (Aristolochiaceae) and the Possible Role of Mushroom-like Scents

抄録

We assessed plausible linkages between floral variation and pollination-system diversity in the genus Asarum (sect. Heterotropa) by investigating the floral-visitor and floral-scent profiles of Asarum asaroides (C.Morren et Decne.) Makino, a large-flowered species endemic to western Japan. Using time-lapse photography and field collections of insects, we confirmed that multiple dipteran families visited A. asaroides. The fungus gnat Cordyla murina Winnertz, 1863 (Mycetophilidae), is likely the primary pollinator, since we observed repeated visits by this species at three spatially distinct sites. We also reassessed the previously posited primary pollinator of A. tamaense Makino and found that C. murina is in fact the likely primary pollinator of this species. The floral-scent profile of A. asaroides typically contains ethyl 3-methylcrotonate, 3-octanone, 3-octanol, safrole, and caryophyllene, and is strikingly different from that of A. tamaense, implying that different mechanisms underlie the attraction of C. murina to these closely related species.