Beetle pollination of Philodendron solimoesense (Araceae) in French Guiana

The pollination of Philodendron solimoesense (subgenus Meconostigma) was studied in four populations of French Guiana. Flowering is asynchronous within each population during July and the flowering cycle is a 2-d process. Numerous insects visit Philodendron inflorescences, but the main pollinator seems to be Cyclocephala colasi (Scarabaeidae, Dynastinae). The pollination process displays aspects typical of beetle pollination: the production of heat and of a strong odor, the presence of a food reward (stigmatic secretion and sterile male flowers), and the presence of a copula don chamber. Flower heat production is important (ca. 11 degrees C above the ambient air) and may help to volatilize the fragrance. Attraction and choice-test experiments showed that C. colasi is not likely to depend on chemical information (such as pheromone) to localize conspecifics but may rely instead on stimuli produced by the inflorescences in order to meet mating partners.