Endothermy by flowers of Rhizanthes lowii (Rafflesiaceae)

Rhizanthes lowii (Beccari) Harms (Rafflesiaceae) is a parasitic plant that grows in the understory of the rainforest in South-East Asia. This plant do es not have leaves, stems, or photosynthetic tissue and is characterised by the emission of a strong odour that attracts the natural pollinators, carr ion flies. Flowers that volatilise odorous compounds and attract carrion fl ies, beetles and other insects are often thermogenic. Here we present evide nce of both thermogenesis and thermoregulation in ii. lowii from microclima te and tissue temperatures measured during different stages of flower devel opment in R. lowii, in natural conditions in Brunei, Borneo. Endothermy was detected in young and mature buds as well as in blooming flowers and even in decaying tissues 3 or more days after blooming. Tissue temperatures were maintained at 7-9 K above air temperature, in both female and male flowers , at all stages of floral development.