OLFACTORY AND VISUAL ATTRACTION OF ERIOSCELIS-EMARGINATA (CYCLOCEPHALINI, DYNASTINAE) TO THE INFLORESCENCES OF PHILODENDRON-SELLOUM (ARACEAE)

Observations and experiments show that Erioscelis emarginata (Dynastinae, Scarabaeidae), the sole pollinator of Philodendron selloum (Araceae), is guided at dusk to the inflorescences in their female stage by a combination of olfactory and visual stimuli. At close range, visual stimuli are induced by olfactory stimuli and the beetles orient themselves by the light inner side of the spathe. Light models are more attractive than dark ones. Nonfragrant spathes or spathe models, which are put closest to the odor sources, are most visited. Odoriferous inflorescences in the female stage emit stimuli for Erioscelis that are present to remain, while in male-stage inflorescences such stimuli are absent. Light inhibits beetles from leaving male-stage inflorescences.