Abai, MR

6th International Congress of DipterologyUnique emergence tube induced by a gall midge (Diptera:Cecidomyiidae) on flower galls in syconia of Ficusmicrocarpa (Moraceae)Yafuso, M. (1) & S. Adaniya (1)(1) Entomological Laboratory, Faculty of Agriculture, University of the Ryukyus,Nishihara 903-0213, JapanWe found two new gall midges (Diptera: Cecidomyiidae) that inducefemale flower galls in syconia of Ficus microcarpa (Moraceae) onOkinawa Island, Japan. Here, we report a unique emergence behavior byone of them. A single larva develops and pupates in each gall. A littlebefore adult emergence, the bottom of each gall elongate to form a tube,which develops, through the skin of syconium, up to 5-6 mm in heightwithin about 7 hours. The pupa crawls out of the gall half way through thetube, or pushes up the bottom of tube with its head and comes out of thegall directly from the base of the tube. Such tube induction has never beenobserved at the time of emergence by other inhabitants of the syconium,such as species of Agaonidae, Pteromalidae, and Torymidae(Hymenoptera). To observe tube tissues, we kept tubes in acetic acidalcohol ( glacial acetic acid : 99.5% ethanol = 1 : 3) for 2-3 days at -15 and transferred into 99% ethanol in a refrigerator. After dehydrated by45% acetic acid, the tubes were dyed with aceto-carmine solution. Under abinocular microscope, we observed a mass of small square cells at the baseand tip of the tube. Exfoliative tissue or layer was not observed at the tubebottom. In the middle part of the tube, long cells were arranged regularly.To confirm if a kind of plant hormone is responsible for the rapid tubedevelopment, a small amount of gibberellin’s paste was applied to thebottom of three galled and three ungalled syconia, but no tubes wereinduced. Further investigations are needed to conform which tissue (orlayer) of the female flower develops and what kind of chemicals areresponsible for the rapid tube development prior to the gall midgeemergence.311