In a study published in the May 2012 issue of Flora, in which Dawn Frame (Herbier IRD de Guyane, part of AMAP research unit) participated and is the contact author, flowers of a species belonging to the Cherimoya family (Annonaceae) were found to mimic foul smelling stinkhorn mushrooms to attract a beetle pollinator.
Duguetia cadaverica was studied at the Nouragues biological field station in French Guiana; it is a small understory tree of primary humid forest and grows from the Guianas to the state of Pará in Brazil.
Duguetia cadaverica © Dawn Frame
Unlike most other members of the Cherimoya family, this species has flowers that “stink”, and are the basis for its name “cadaverica”. To better understand the pollination system in these fetid flowers, the researchers studied the reproductive biology of the plant and analyzed flower scent composition.
Flower of Duguetia cadaverica © Dawn Frame
The researchers described the scent as “reminiscent… of very mature Camembert cheese, mushrooms and old damp socks with an additional vomit-like note…”
Scent analysis revealed a novel mix of three chemical classes and the most abundant belong to a group of molecules that are known to give mushrooms their characteristic earthy, moldy aroma. The two other classes of molecules that they found are associated with cheese and decomposing cadavers.
Flower scent collection of Duguetia cadaverica © Dawn Frame
The only insect visitors to enter the flowers are small beetles of a single species of Pycnocnemus (Nitidulidae), which is new to science. What is interesting is that this group of beetles is normally only found on stinkhorn fungi (Phallales) where they feed and reproduce.
Based on this and supplementary evidence, the researchers conclude that the flowers of Duguetia cadaverica mimic stinkhorns by both scent and visual cues to deceive the small beetles into acting as pollinators.
This special system is an example of “saprocantharophily”, that is, pollination by beetles (-cantharophily) attracted to decomposing material or decomposers (sapro-); saprocantharophily is quite rare and known from a few plants such as several Araceae and Hydnoraceae (a root parasite).
Even rarer are flowers that mimic the fruiting bodies of fungi; this phenomenon is known only from three families (Araceae, Aristolochiaceae and Orchidaceae); in these cases, the pollinators are flies that become trapped for a time in the flower. The researchers investigating Duguetia cadaverica point out that the open floral chamber in Duguetia cadaverica is very different from “trap” flowers, and for this and other reasons, flies cannot be pollinators of this plant.
References of the publication:
A novel pollination mode, saprocantharophily, in Duguetia cadaverica (Annonaceae): A stinkhorn (Phallales) flower mimic
Holger Teichert, Stefan Dötterl, Dawn Frame*, Alexander Kirejtshuk, Gerhard Gottsberger.
Revue Flora, volume 207, pages 522-529.
* Corresponding author.
To view the publication: http://www.sciencedirect.com/science/article/pii/S0367253012000898
