Study Of The Mutualism Between Epicephala Moths And Phyllantheae Plants

Different coevolution mutualisms exist between Epicephala moths andPhyllantheae plants. In the long course of coevolution, various kinds of mechanismshave been developed to maintain the balance of interest and the stabilization of themutualism between them. The present dissertation focuses on the study of theEpicephala moths associated with Glochidion and Breynia plants in Hainan andFujian. The results showed that “one-to-two” and “two-to-two” diffuse coevolutionsalso exist in the Epicephala—Phyllantheae mutualisms except “one-to-one” specificcoevolution. Based on the morphological characters, the flower-visiting behavior andthe biological characters of the Epicephala adults and larvae, as well as themorphological characters of flowers, the phenology and the seed production of theassociated hosts, we discussed the different coevolution models between theEpicephala moths and the corresponding hosts, and the mechanisms to keep theirstability. This dissertation consists of the following three aspects:(1) Four new species of the genus Epicephala are described and illustrated, ofwhich E. lativalvaris Li, Wang et Zhang,2012, E. mirivalvaris Li, Wang et Zhang,2012and E. vitisidaea Li, Wang et Zhang,2012parasitized on Breynia plants, and E.eriocarpa Li, Wang et Zhang,2012parasitized on Glochidion eriocarpum. TheEpicephala mature larvae of14species are dissected; the head and body chaetotaxy ofthe mature larvae are described in detail and illustrated, along with a key for theidentification of these larvae; and the differences among the Epicephala mature larvaeon different hosts are compared.(2) Based on the study of the Epicephala moths and the related hosts in Hainanand Fujian, we found “one-to-one” specific coevolution between E. vitisidaea and B.vitis-idaea;“two-to-two” diffuse coevolution between two Epicephala moths species(E. lativalvaris and E. mirivalvaris) and two of Breynia plant species (B. fruticosa andB. rostrata), and “one-to-two”diffuse coevolution between E. bipollenella and twoGlochidion plant species (G. zeylanicum and G. hirsutum).In E. vitisidaea—B. vitis-idaea coevolution system, the special characters of bothpollen grains and stigma concealed in the sepal lobes made other pollinators unable topollinate B. vitis-idaea flowers except Epicephala moths; the flower-visiting time of E.vitisidaea coincides with the blossom of two B. vitis-idaea male flowers, and the lifehistory of E. vitisidaea coincides with the phenology of B. vitis-idaea ensured thespecifity of pollinators; the peak emergence of E. vitisidaea is longer than theblooming period of B. vitis-idaea, and the active and high efficiency of pollinationensured the development of ovaries. Breynia vitis-idaea controled the survival rate ofE. vitisidaea larvae by the presence or absence of the basal stalk, and the E. vitisidaealarvae consumed a portion of seeds so that Breynia vitis-idaea would have enoughintact seeds left to maintain the population size. In Epicephala—Breynia diffuse coevolution system, the two Epicephala mothsspecies jointly and actively pollinated the two Breynia species, and a singleEpicephala larva could develop to maturity by consuming all six seeds of each fruit,whereas a fraction of intact fruits were left to ensure the reproduction of the plantswithin the whole population. The life history of Epicephala species highly coincideswith the phenology of Breynia plants, and the different phenology of B. fruticosaresulted in different life history of the two Epicephala species in Hainan and Fujian.The two Epicephala species are competitive for resources, and the population of E.mirivalvaris is much smaller than that of E. lativalvaris. The natural hybridization ofthe two host plants, possibly induced by sharing pollination of Epicephala moths, isbriefly discussed.In Epicephala—Glochidion diffuse coevolution system, the life history of E.bipollenella coincides with the phenology of the two Glochidion plant species, and theflower-visiting time of E. bipollenella highly coincides with the blossom of the twoGlochidion flowers. The seed setting rate of G. zeylanicum and the parasitic rate of E.bipollenella are higher than those of G. hirsutum, but G. hirsutum possesses moreintact seeds per fruit than G. zeylanicum, which maintained the balance of the twoGlochidion species population.(3) Based on CO1genes of20Epicephala species and matK genes of22Phyllantheae species, we discussed the coevolution process of Epicephala andPhyllantheae (Breynia, Glochidion and Phyllanthus).