The plants are toxic and few animals can eat them. Diurnal moths of the subfamily Uraniinae feed on them. These moths are species of the genus Urania in the Americas, and of the genus Chrysiridia in Africa.
The only species from mainland Africa is from Tanzania is O. mansfeldiana, a liana from Tanzania . The Madagascan species are O. ankaranensis, a shrub from the limestone karst of northern Madagascar, O. palmata Leandri, a dry forest shrub closely related to O. ankaranensis but from western Madagascar, O. occidentalis Leandri, also a dry forest species of western Madagascar, and O. oppositifilia (Willdenow), a tree from the east coast rainforest of Madagascar.[7]
The Madagascan sunset moth (Chrysiridia rhipheus) feeds on all four of these species.
^1821 illustration from The botanical cabinet, consisting of coloured delineations of plants from all countries by Conrad Loddiges. London, C. Loddiges & Sons, etc., 1821, volume 6 (plate 519).
^Govaerts, R., Frodin, D.G. & Radcliffe-Smith, A. (2000). World Checklist and Bibliography of Euphorbiaceae (and Pandaceae) 1-4: 1-1622. The Board of Trustees of the Royal Botanic Gardens, Kew.