<S2-2> Geographical variation of mutualistic relationships between Macaranga myrmecophytes and their ant partners: research plans in Sarawak

Abstract

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.