scent and form

[Bonaventure Magrys]

Susanne writes:
"The answer to both questions is yes.  The fungus gnats that pollinate
Arisaema in the wild use scent to find their matig and oviposition
sites.  Details can be found in

Vogel, S. 1990. The Role of Scent Glands in Pollination.  Transl. of
S. Vogel's 1963 German
original, with an introduction by S. S. Renner and a new
index to scientific
names.  Washington, D.C., Smithsonian Institution Libraries, 203
pp.
Vogel, S., and J. Martens. 2000a. A survey of the function of the
lethal kettle traps of Arisaema (Araceae), with
records of pollinating fungus gnats from Nepal. Bot. J. Linn.
Soc. 133: 61-100.
Vogel, S., and J. Martens.. 2000b. Die t=F6dlichen Kesselfallen von
Arisaema (Araceae). Linzer Biol. Beitr. 32: 715-716."


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Interestingly, the slipper orchid Paphiopedilum rothchildianum has
a similar pollination mechanism. I was just perusing some web sites with
its image and recalled this fact. The gnats are attracted to the hairy
"bee's knees" staminode in the center of the flower. Notice how the
striping of the dorsal sepal resembles an Arisaema spathe:
http://www.ladyslipper.com/pproth.htm
http://www.theorchidzone.com/paph/roth7b.htm
http://www.urban.ne.jp/home/nakagawa/photo/paph_ro1.htm
Other Paphs have long petals possibly to entice insects (or the
horticulturalist). Witness the closely related
http://www.sonic.net/~soa/sanderianum4.htm
http://www.notsogreenthumb.org/galleries/Lookatmine/OrchidHTMLFiles2/paph_sanderianum2.htm

Bonaventure