Re: Iris Pollinators
- To: Multiple recipients of list <i*@rt66.com>
- Subject: Re: Iris Pollinators
- From: B* S* <b*@tiger.hsc.edu>
- Date: Mon, 5 May 1997 07:26:28 -0600 (MDT)
The observation of a hummingbird moth (hawk moth) possibly pollinating iris
flowers was intriguing, so I called a friend who studies pollination
biology.
He thought that the design of the iris flower (to be pollinated by large
bees like bumblebees) and the behavior of the hawk moth, which hovers in
front of flowers sipping nectar with a long tongue, would be a misfit and
that the moth could not pollinate the iris flower.
In order for an iris flower to be pollinated, the insect, usually a
bumblebee or other large bee (depends on the size of the flower) must
actually land on the fall petal and force its way under the style arm. The
stigmatic shelf on the style arm then scrapes off any pollen the bee is
already carrying, and the anther subsequently dusts the bee with new
pollen. The bee, meanwhile, gets a reward of nectar from deep in the
flower. In bearded or crested irises the process is made more certain by
the beard, which forces the bee to "stand on tiptoe" while getting its
drink and thus more surely press its back against the reproductive
apparatus.
Hawk moth-pollinated flowers are usually white, for greater reflectivity in
low light, relatively flat, and have long, projecting styles and stamens.
I see a lot of hawk moth activity around rhododendrons, particularly the
very fragrant R. alabamense, blooming here now. They also seem to like
Monardas, which don't really fit the picture and look more like
bird-pollinated flowers.
Bill Shear
Department of Biology
Hampden-Sydney College
Hampden-Sydney VA 23943
(804)223-6172
FAX (804)223-6374
email<bills@tiger.hsc.edu>
