乾 陽子

This proceeding is a compilation of findings and progress activities of research collaboration between the Forest Department Sarawak (FDS) and the Japan Research Consortium for Tropical Forests in Sarawak (JRCTS). To highlight the research findings, An International Symposium entitled "Frontier in Tropical Forest Research: Progress in Joint Projects between the Forest Department Sarawak and the Japan Research Consortium for Tropical Forests in Sarawak" was ii held in Kuching, Sarawak on 21-22 September 2015.Myrmecophytes have mutualistic associations with plant-inhabiting ants (so-called plant-ants). They provide plant-ants with nest space and sometimes foods, and in return, the plant-ants protect their host-plants against herbivores, pathogens and climbing plants. In the tree genus Macaranga (Euphorbiaceae), 26 species are myrmecophytic, among which 18 species are distributed in Sarawak. The relationships between Macaranga myrmecophytes and plant-ants are remarkable for their high species-specificity and strong interdependency. For 20 years, we have studied the myrmecophyte-plant-ant relationships and their effects on the herbivorous insect assemblage associated with Macaranga plants at Lambir Hills National Park (LHNP), where 17 Macaranga species, including 12 myrmecophytic species, are distributed. Here, we describe 1) some ecological characteristics of Macaranga myrmecophytes, 2) the main results of our studies on the character of the mutualisms and their ecological consequences, and 3) our new research plans in Sarawak to investigate the geographical variations in the mutualisms. In our future research, we will enhance collaboration with Sarawakian researchers.

This proceeding is a compilation of findings and progress activities of research collaboration between the Forest Department Sarawak (FDS) and the Japan Research Consortium for Tropical Forests in Sarawak (JRCTS). To highlight the research findings, An International Symposium entitled "Frontier in Tropical Forest Research: Progress in Joint Projects between the Forest Department Sarawak and the Japan Research Consortium for Tropical Forests in Sarawak" was ii held in Kuching, Sarawak on 21-22 September 2015.Two myrmecophilous insect taxa on myrmecophytes (ant-plants) were studied, Arhopala (Lycaenidae) butterfly larvae feeding on Macaranga ant-plants and a monotypic cockroach genus inhabiting epiphytic ant-ferns. The chemical profiles of cuticular hydrocarbons did not always match between these myrmecophilous insects and the associated ants on the ant-plants. Chemically, Arhopala dajagaka showed good mimicry of the host ant species, A. amphimuta does not mimic, and A. zylda lacked hydrocarbons and thus appeared to be chemically insignificant. The cuticular hydrocarbons of Pseudoanaplectinia yumotoi cockroach were propagated among the host ant colonies. It is suggested that considerable variations exist in the chemical strategies that the myrmecophilous insects on ant-plants use in order to avoid ant attack and profit from the ant-plant associations.