Re: Philodendrons produce infrared light???
- Subject: Re: Philodendrons produce infrared light???
- From: &* W* <h*@witmore.net>
- Date: Wed, 21 May 2008 08:13:51 -0400
|
Hasn't there been research about this associated with
Skunk Cabbage (Symplocarpus foetidus)?
Harry
Witmore
Cloud
Jungle Epiphytes
www.cloudjungle.com From: aroid-l-bounces@gizmoworks.com [mailto:aroid-l-bounces@gizmoworks.com] On Behalf Of ExoticRainforest Sent: Tuesday, May 20, 2008 9:10 AM To: Discussion of aroids Subject: [Aroid-l] Philodendrons produce infrared light??? Since Saturday of this past week, Julius Boos, Leland Miyano,
Christopher Rogers and I have been discussing the possibility (probability) that
infrared may be involved in the process of thermogenesis and pollinator
attractaction within aroids. It appears to us, and Christopher is the only
trained scientist among us, this concept is very likely possible!
I personally find it interesting that I've not read of any
research within the aroid community on this concept. With the help of all
of these, as well as by doing some research on the IAS website and by reading
information within Simon Mayo, J. Bogner, and Pete Boyce's great text on Araceae
as well Dr. Croat's journals along with Deni Bown's book, I have prepared a
response to the fellow in London who originally made the post on UBC asking if
he had actually observed "infrared light" involved in the anthesis of his
Philodendron bipennidifidum. Now is where I really need the input
of all you honest to goodness aroid scientists out there on this
forum!!
The University of British Colombia plant discussion website
has been offline due to a server failure since Sunday. As a result, this
has not been posted. I would very much like input from any of the world
class aroid botanists who read this forum. Tell me if I have my facts
right and if I got something wrong, what do I do to correct it? I'd
personally really like to see this discussion continue on the Aroid l
forum!
If this is possible, and it certainly appears it may be a part
of thermogenesis as well as an attractant feature for the pollination of aroid
species, I'd love to learn more. I'm not a scientist and what I've written
is based solely on what I can read along with the input of Christopher, Julius
and Leland. But if this idea has merit, it would certainly appear more
research would be useful to our community.
Now, this is my post which will be made once the UBC server is
back online. If you see errors or anything that needs to be addressed,
please point it out! The post is addressed to the fellow who asked the
original questions.
One point if I may addressed solely to the readers of this
forum. I know a lot of people are relatively new on Aroid l since I often
see new names asking questions or responding to ones posed by others. Our
community is composed of people who have an interest in aroids and as such
should have an interest in the International Aroid Society. I'm going to
steal Julius' podium and suggest that if you have not taken the time to join
IAS, please do so right now! The $20 per year you will spend will come
back to you many more times than you realize! And if you are not using the
IAS website to answer your own questions about aroids, you have missed one
incredible source! Please consider joining right now!
Steve Lucas
Chris, it appears possible you may have opened a new door
in understanding more of the pollination of Philodendron species.
Whether you have simply made an observation or a discovery is yet to be
determined and I am certainly not qualified to comment. I am now receiving
a stream of mail from researchers and skilled aroid experts who find your
observations of interest.
The one thing that would have been of greatest benefit
would have been that you had a better understanding of what you were observing
at the time you took your measurements. By understanding what was
happening you would have been better able to more accurately record
information at the critical phases during anthesis.
Now, let me state I am not an expert in this field. I
just study it a great deal and spend a lot of time discussing information
with people who are experts. Don't take everything I write here as
science fact, just take it as a basis for your own studies. Since you
are apparently relatively close to the Royal Botanic Garden Kew in London I
would strongly recommend you attempt to seek an appointment with Dr. Simon Mayo
who is one of the world's top aroid botanists and experts in
Philodendron species, especially those from Brazil. Your
specimen of Philodendron bippidifidum is a Brazilizian
Philodendron species. Simon is one of the authors of a scientific
text entitled The Genera of Araceae. That text is
quite costly, around $180 per copy U.S., but if you are interested in persuing
this endeavor you will learn a great deal about pollination within that text
written by Simon, J. Bogner and Pete Boyce. It is the single most
comprehensive such text available. In addition, secure a copy of Deni
Bown's text, Aroids, Plants of the Arum Family. This book
is relatively inexpensive and available from Amazon.com. Deni's book is
jam packed with aroid information with more than a single discussion of the
processes you observed.
I have several follow ups which I will be posting but for
now I'd like to give you some "food for thought" regarding what you
observed.
Aroids are pollinated by insect species, often very specific
"assigned" species. The vast majority of
Philodendron are often visited by the male of a beetle species found
within the genus Neelia, although these beetles do not appear to feed
nor mate on the inflorescence. It appears only larger beetles actually do
the work of pollination. The pollinators appear to be members of subfamily
Dynastinae in the family Scarabaeidae. Many belong to
the genus Cyclocephala and have been recorded as pollinators
of Philodendron and other aroid genera. Some of these beetles are
not particularly species specific and visit more than a single
Philodendron species, however it is surmised the height of the plant may be
a particular attractant to individual beetles thus causing them not to cross
pollinate other Philodendron. Those beetles are generally drawn
to the Philodendron inflorescence in the late day or at dusk and are
apparently attracted by a combination of pheromones (scent) and a source of food
and shelter which is composed at least in part of an oil produced on the
staminate flowers containing lipids along with the enclosure of the
spathe. Shelter may play a part since the male often brings along his mate
in order to breed at the same time.
Some Philodendron species have sweet smelling
pheromones while others show no noticeable aroma. The one you observed,
Philodendron bipennidifidum, appears to have been attractively
scented. This aroma is produced by the sterile male flowers on the
inflorescence which are attempting to entice a pollinator, and to the male
of that insect species that scent may be similar to the same pheromone
that attracts him to a mate when she is ready to be impregnated. This
point is not factually certain within Philodendron. Anthesis is
composed of two primary stages, female anthesis at which time the pollinator is
attracted and male anthesis during which time pollen is produced to be carried
to another plant. Some species are capable of self pollination, but not
all. And as you will read later, a very unusual but common chemical source
may also help to prevent self pollination.
During anthesis (both female and male) the open spathe of the
Philodendron provides space for protection and often entices
these beetles to use that area for feeding along with a place to safely
copulate. The plant provides a source of nutrient rich lipids which is an
excellent food source for the beetles, but the plant also benefits. It is
not uncommon for the beetles to spend the night within the spathe and spadix of
the host Philodendron and they frequently mate during this
period. So why do they spend the night? Thermogenisis! Quite
simply, the spadix can warm enough to be noticeable to the touch and for the
insects that may be tired from traveling long distances to perform their
required tasks this additional source of heat in the rain forest creates a
microclimate and may actually increase their metabolism and encourage them to
explore all portions of the spathe and spadix. Quite simply, a
microclimatic zone of warmth is now being generated within the spathe that
offers both comfort and protection along with food. This feature alone may
increase the chance of self pollination within the specimen, but another
may inhibit the same.
The thermogenesis produced by the plant during anthesis, which
is simply a natural heat produced by many living beings, appears to stimulate
the beetles into this period of copulation. Of major interest, even
though the effects of thermogenesis have been observed for over 200 years, not
until relatively recently did anyone know the cause. So what is the
chemical cause? Salicylic acid, the same compound used to manufacture
aspirin! The salicylic acid begins not only the heating process but also
the production of the pheromones (scent). This unique process is not
limited to Aracea (aroids) but is also found in other plant genera. Read
Deni Bown's book for a more complete explanation. Of interest, salicylic
acid may also help to prevent self pollination which is an interesting
contradiction in and of itself.
The thermogenesis (thermo
genesis. "Heat Birth" or heat production) caused
by the salicylic acid appears to be one of the stimulators to cause the
beetles to be active and as a result to both feed and copulate. It is
known the rate of thermogenesis (heat rise) is sometimes dramatic. And
that may be what you observed with your IR thermometer. However,
thermogenesis does not produce a consistent temperature since the highest
temperatures appear to last only 20 to 40 minutes. In fact, it may be the
visit of the beetles that contributes to the effect botanists know as
thermogenisis.
I'm sure you are now questioning why you didn't see any
beetles, and that raises a new group of questions since scientists have known
for a long time they don't need to be present for thermogenisis to manifest
itself. But the presence of beetles does appear to increase the
temperature produced by the event. The temperature increase appears to
increase the amount of pheromone being exuded by the tiny flowers, thus the
strength of the pollinator attractant. Up to 200 beetles at a single time
have been observed on a single inflorescence during anthesis! However, the
normal number is closer to 5 to 10. Researchers have noted the highest
temperatures appear to occur during the period when the highest number of
beetles are present. However, the exact role of thermogenesis is
still not well understood and your observations "may" have opened the door
for additional research. Right now, no one appears to know if
research on infrared heat in relationship to an attractant role is being
done.
You just observed both female and male anthesis without fully
understanding what you were watching. The first stage is when the
female flowers are ready to be pollinated and the production of the attractant
pheromone along with thermogenisis begins. Female anthesis in
Philodendron can last approximately 2 days. That stage is
followed often a day or so later by male anthesis which is the point when
pollen is produced. The pollen often appears to be a stringy substance as
you observed. The beetles often visit a separate inflorescence in the
male stage of anthesis prior to visiting an inflorescence beginning female
anthesis and thus collect pollen on their bodies and transfer that pollen from
one healthy specimen to another in need of pollination. All of this is
within Nature's ingenious design to keep the ecosystem strong and
healthy.
Now, here are the questions at hand. Is the infrared
heat you observed directly related to thermogenesis or something entirely
different? Does the infrared heat have any impact as an attractant on the
assigned beetle pollinator? I really cannot offer an opinion although it
certainly appears plausible. I asked several interested
experts as explained in another post and these interesting responses I
received from D. Christopher Rogers, Senior Invertebrate Ecologist/Taxonomist,
EcoAnalysts, Inc. stood out, "Infrared
thermometer works by detecting radiation in the IR spectrum. IR radiation is
emitted by all objects depending on their temperature. IR is a color like any
other part of the electromagnetic spectrum, just like visible light, but we just
cannot see it, although many insects and crustaceans can, as well as some birds.
Just an aside: some raptors can see the urine tracks
in infra red left by rodents who just dribble wherever they go and so know which
areas to concentrate on for prey items. So, there is IR color and
also IR radiation emitted by all objects. The higher an object’s temperature,
the greater the object’s IR radiation. The IR thermometer does not tell you the
color of an object, it tells you the heat it is radiating by a correction factor
multiplied times the IR radiation. This is exactly how the IR camera and
thermometer work. But it must know what the basic background temperature is to
calibrate itself.
So, metabolic reactions will
generate heat, which is measurable in the IR spectrum. One of my favorite
aroids is Helicodiceros muscivorus, the Dead Horse Arum. The cells in the
spadix are packed with mitochondria, which are the cell powerhouses. As a
result, they raise the temperature of the plant to a wonderful 98.6 degrees F
when they are in bloom and producing their macabre odors. It seems to me that
anthesis is probably very costly (in energy) to the plant. So, the mitochondria
are working hard to move anthesis along, spending lots of energy, much of which
is lost as heat, and therefore generating an increase in IR radiation. Since
insects do cue in on pheromones and the IR discharge in those pheromones, it
seems a very logical step for the plant to exploit in the attraction of
pollinators. Obviously, since Helicodiceros, Amorphophallus and Typhonium
all produce heat from the spadix appendix (possibly to volitalize scent
molecules as well as to add allure to the deathly perfumes) it seems that the
ability would be found residing in other aroids as well."
Christopher then continues responding to the question of the
possibility infrared is involved in the process of anthesis as an attractant,
"YES!!! Many insects respond to infrared.
This is why the moth (and some many other insects) come to the flame (porch
light, candle, mercury vapor bug collecting light, et cetera). One paper I
remember reading discussed how certain moths produce IR. The female corn ear
worm rubs her body building up a static electricity charge through friction. She
releases her pheromones in a cloud and then discharges the static charge into
the cloud giving an IR flash, attracting mates (and a few predators and
parasites!!) towards her. So again, plants could easily be using IR as well as
pheromonal tricks to attract pollinators.
Mosquitoes do a similar
thing; when I was working for the State Health Department on mosquito borne
diseases, I used a CDC trap. This trap is a bucket filled with dry ice (carbon
dioxide) over a very small “wheat grain” light. Female biting mosquitoes follow
the CO2 (assuming it to be exhaled breath) to find a good host, but then focus
on the IR glow of the tiny light as the exact source, after following the CO2
trail. When they approached the light, they were then sucked into a chamber by a
small fan." So, now that we can establish the fact infrared can act as an attractant we are still left to ponder whether or not it will act as an attractant to the specific beetle species involved with Philodendron. I'm not sure if anyone knows the answer. But here is some conjecture that is being batted around as a result of your post. The current questions are asking if it could be possible if the initial attractant is the pheromone which acts more like a long range invitation and "aims" the beetles toward the plant that is now nearing female anthesis? It is known from the study of orchids that many of these assigned insects can sense a single molecule of the pheromone from up to one mile away. But that leads to a another question. Is it the thermogenesis that is the final attractant attracting the beetle and his mate to a source of food? Or is it possible the infrared heat also severs in addition to the pheromone attractant. In other words, the infrared heat could possibly act as a "neon sign" which is basically blinking "Eat Here, Sleep Here, Have Sex Here"! Is that possible? I just do not know! But you have posed some interesting thought. Again, I strongly recommend you consider buying and reading the text by Dr. Mayo, J. Bogner and Pete Boyce as well as Deni Bown's text. These three scientists are among the best in the world when it comes to aroid species. Deni is an accomplished writer but the facts posed in her text are well researched. Additional great information can be found in the Annals of the Missouri Botanical Garden 1997, volume 84, #3 by Dr. Thomas B. Croat. Pose your theories to Simon if you can manage an appointment at the Kew. In the meantime, I can assure you there are now some in the United States who have shown interest. Will it prove anything to which you can claim credit? I have no idea. I'm just a writer/photographer who loves to study aroid species. Just one additional note. The information presented here was gathered from the International Aroid Society website http://www.aroid.org/ as well as from the texts mentioned. Input on this was given by aroid experts Julius Boos and Leland Miyano in addition to the named sources. If you are truly interested in learning more about your aroid specimen I would urge you to consider joining the IAS. You can do so by clicking on the link above. The $20 per year you will spend on membership will come back to you many times in journals and information alone. You will quickly learn many of the members of the International Aroid Society are extremely knowledgeable about the plants they grow and they are quite willing to share information.
No virus found in this incoming message. No virus found in this outgoing message. |
_______________________________________________ Aroid-L mailing list Aroid-L@www.gizmoworks.com http://www.gizmoworks.com/mailman/listinfo/aroid-l
- Follow-Ups:
- Re: Philodendrons produce infrared light???
- From: M* G* &*
- Re: Philodendrons produce infrared light???
- Prev by Date: Re: leaf beetles on aroids
- Next by Date: Re: Philodendrons produce infrared light???
- Previous by thread: Re: Philodendrons produce infrared light???
- Next by thread: Re: Philodendrons produce infrared light???