Evolution of gall inducing Eulophidae (Hymenoptera: Chalcidoidea) on Myrtaceae in Australia

Abstract

The present thesis consists of two main parts: 1) descriptive works including new species descriptions and a gall community study and 2) phylogenetic studies. The major aim is to determine the evolutionary pathway of gall induction biology among Australian parasitic Tetrastichinae (Hymenoptera: Eulophidae). The descriptive works include three new gall inducing tetrastichines; Quadrastichus erythrinae Kim from Erythrina (Fabaceae) as the first gall-former in the genus, Moona spermophaga Kim and La Salle from seeds of Corymbia (Myrtaceae) and Leprosa milga Kim and La Salle from seeds of Eucalyptus (Myrtaceae). Also, a new gall inducing tribe Boucekelimini has been described from Melaleuca (Myrtaceae), and this new tribe contains two new genera Boucekelimus Kim and La Salle and Tatiana Kim and La Salle. A gall community study including species composition, abundances and seasonal occurrence was conducted. This gall community on Eucalyptus appears very complex in its species composition and interactions among gall-formers, parasitoids and inquilines. The wasp community consists of twelve species of five families in two hymenopteran superfamilies. Two unidentified Ophelimus speices (Eulophidae: Ophelimini) are dominant species among wasps emerged from the galls. The first Ophelimus species was found to be a primary gall-former. The second Ophelimus seems to be a parasitoid or an inquiline of the first Ophelimus. All other associates seem to be parasitoids or inquilines. Morphological and molecular data were used to infer the evolution of gall induction biology on Eucalyptus in Australian Tetrastichinae. Also the combined analysis with both morphological and molecular data was conducted. Each morphological, molecular and the combined analysis yielded contradicting results. 47 characters from 24 tetrastichine species and two outgroup species were used for the morphological analysis. Cladograms were constructed, and the results were compared with Graham's suggestion (1987) about relationships among the tetrastichine genus groups. His suggestion was largely contradicted by the present analyses. The analyses suggested that both the Aprostocetus-complex and the Tetrastichus s. str. are nonmonophyletic. However, some group clustering appeared to fit relatively well with Graham's suggestion: Aprostocetus + Neotrichoporoides, Crataepus + Pronotalia, and the separation of the Australian gall inducing group from the European fauna. The barcoding region (619 bps fragment) of Cytochrome Oxidase subunit I (COI) on the mitochondrial gene was sequenced from 25 tetrastichines as ingroup and one outgroup species. The Barcode gene failed to resolve phylogeny at genus level but is very useful for identification of species in a genus or cryptic species. Molecular analyses found that the Leptocybe species group consists of seven unique sequences. Two species in this species group drew my attention: Leptocybe invasa Fisher and La Salle, which is a devastating invasive pest in Israel, and Leptocybe sp. 9, which was most recently found in Australia. They were thought to be the same species due to the same biology and gall type. However, the molecular analyses suggest that Leptocybe sp. 9 is not L. invasa but a very close species. The evolution of gall induction on Eucalyptus among Australian Tetrastichinae was estimated from the morphological and molecular data. Overall, the morphological analysis suggests two independent origins of gall induction on Myrtaceae in Tetrastichinae while the combined analysis only one origin. Also, the results of the analyses suggest that gall inducing lineages may have evolved from a parasitic progenitor and the ancestral stock of the Australian gall-inducers may have first induced galls on seeds of Eucalyptus. Leaf galling and leaf & twig galling genera except Epichrysocharis may have evolved deep within the seed-galling lineage