Geissorhiza Research Update

Evan Eifler evan.eifler@gmail.com
Wed, 27 Sep 2017 14:06:24 PDT
Hi Everyone! I'd like to post a short update on the work I'm doing this
week with the radiant winecup (Geissorhiza radians) and its look-alikes,
but first I'd like to remind you that there are only 3(!) days left of my
crowdfunding campaign so if you've been considering donating, now's the
time. And if you haven't already, please forward the link to anyone you
think might be interested. I know many of you in North America have been
donating to hurricane relief and that comes first, absolutely, but it's
also important to fund scientific research, especially environmental
research now, before it's too late and this weather becomes the new normal
which could spell the end for Critically Endangered species already
teetering on the brink like many I'm working with.

https://experiment.com/projects/…
Once again, I'm posting the text here, but please visit the lab note on my
crowdfunding campaign for the photos that go along with the text - well
worth the extra click! Link below

https://experiment.com/u/xC5uLg/


Can you spot the difference between each of the flowers below? If not,
you're not alone; it's likely their pollinators can't either. But what's
going on here? Is one mimicking the other to co-opt it's pollinator? Does
their pollinator just prefer this blue and red pattern which has caused the
convergent evolution of these species to one optimal color pattern? Is the
pollinator hardwired to prefer this pattern or is it a learned response? I
certainly can't say... yet. What I can tell you is that these are each
separate species, they overlap in distribution, flower at the same time,
and, although from two separate genera, they all look almost exactly alike!

I'm back in Darling with renown pollination biologist, Steve Johnson,
trying to figure it all out. We're gathering preliminary data on these
species' pollination systems so that we may design a rigorous set of
experiments to untangle who might be mimicking who and to reveal the
pollinator's taste in flower color and pattern. It's possible that some of
the flowers are rewarding (offer nectar) and one is not so that the
non-rewarding species is a Mullerian mimic of the others. This is a common
syndrome in orchids but has never been observed in the iris family. Today
we made novel pollinator observations that confirm at least three of these
species share a pollinator, a tabanid horse fly, so we are already laying
the groundwork for a fascinating study to come. I've taken tissue samples
from each of these species so it will be interesting to make the phylogeny
and see exactly how they're related - it's possible they're not even each
other's closest relatives. There's already a dated phylogeny for Babiana so
comparing the two should give us an idea who came first. Off the cuff, I'd
say the Babiana because it's an older lineage, but after looking back at
the phylogeny it appears that Babiana rubrocyanea is one of the most
derived members, meaning it is one of the most recently evolved. So who
knows?!

As I've been thinking about this today, I can't help but be concerned for
the future of this incredibly intricate and fragile web thousands, if not
millions of years in the making. If each of these species depend on the
others and each of these species is already severely threatened, how are
they and the other symbioses of the Cape going to weather further human
impact either directly through habitat loss or indirectly through alien
species invasion and climate change? If one goes, do they all go?
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