Biology Reference
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pollination while sculptured pollen grains are associated with biotic polli-
nation. We tested the statistical significance of an association between pollen
ornamentation and pollination system in two families of the monocotyledons,
the Araceae and the Arecaceae, taking into account the phylogenetic frame-
work.
Findings
Character optimization was carried out with the Maximum Parsimony
method and two different methods of comparative analysis were used: the
Concentrated-Change test and the Discrete method. The ancestral ornamen-
tation in Araceae is foveolate/reticulate. It is probably the same in Arecaceae.
The ancestral flowers of Araceae were pollinated by beetles while ancestral pol-
lination in Arecaceae is equivocal. A correlation between ornamentation type
and pollination was highlighted in Araceae although the results slightly differ
depending on the method and the options chosen for performing the analyses.
No correlation was found in palms.
Conclusion
In this study, we show that the relationships between the ornamentation type
and the pollination system depend on the family and hence vary among tax-
onomic groups. We also show that the method chosen may strongly influence
the results.
Findings
The exine wall of the pollen grains of flowering plants displays patterns of orna-
mentation (the external aspect of pollen grains, also called sculpturing) that are
highly diversified. The reasons accounting for such variation in the ornamenta-
tion of pollen grains in flowering plants still remain unclear. Among the different
types of relationship implying pollen ornamentation that have been suggested,
the existence of a link between exine sculpturing and pollinator type has often
been proposed and was even evidenced in certain situations. It is often considered
that smooth pollen grains are associated with abiotic pollination (wind or water)
while echinulate or reticulate pollen grains are associated with biotic pollination,
particularly entomophily [1,2]. These results show that the adaptiveness of this
character still remains largely debated.
The study presented here aims to test the hypothesis suggested by Grayum [3]
concerning a relationship between pollen ornamentation and pollinator type in
the Araceae, using Phylogenetic Comparative Methods. He established a correla-
tion between (a) psilate and verrucate pollen and pollination by beetles and (b)
