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Carnivorous Plants Glow to Attract Prey

Carnivorous plants have an arsenal of tricks to entice insects into their clutches. These predatory plants have been known to use bright colors, delicious nectars, and appealing smells to make quick meals of the bugs that come to investigate—but no one knew they could also glow a bright blue.

carnivorous plant picture

The pitcher plant Nepenthes khasiana glows blue. Photograph courtesy Rajani Kurup, Anil J. Johnson, Sreethu Sankar, and Sabulal Baby

 

The flesh-eating flora have special cells that help them generate an ultraviolet hue, according to a new study published in the journal Plant Biology. Though invisible to the unaided human eye, the fluorescence is quite alluring to an inquisitive insect. (See pictures of killer plants.)

“To the best of our knowledge, this is the most distinct fluorescent emission found in the plant kingdom,” said study author Sabulal Baby, a plant biologist at the Jawaharlal Nehru Tropical Botanic Garden and Research Institute in India.

The glow is actually a survival technique: Carnivorous plants most often grow in nutrient-deficient soils and have to catch and kill bugs to supplement their poor diets.

Like Moths to a… Glow Stick

The plants’ light is emitted as an ultraviolet wavelength tailored to appeal to potential prey, including insects and other arthropods, the group that includes crustaceans, insects, and spiders. Insects often can see wavelengths that emphasize food sources.
For example, research suggests that honeybee eyes have evolved to pick out the brightest—and hopefully most nectar-rich—flowers.

 

carnivorous plant picture

The plant Sarracenia purpurea glows in UV light. Photograph courtesy Rajani Kurup, Anil J. Johnson, Sreethu Sankar, and Sabulal Baby

 

To an insect, the carnivorous plant’s glow probably looks like a bonfire. But to people looking at the plant under a black light, it’s something like a glow stick.

“In normal light, humans are not going to see this,” Baby said. “In the scale of a small ant, this could be a very clear light to them.” (Also see: “Glowing Animals: Beasts Shining for Science.”)

Fatal Attraction

Baby and his team examined four major types of carnivorous plants: pitfall traps, flypaper traps, snap traps, and bladder traps. Pitfall traps use pools of water or nectar to drown victims, while flypaper traps secrete sticky substances to snag a live snack.

Snap traps make some of the fastest movements in the plant kingdom, rapidly closing around prey, and bladder traps suck in prey using an internal vacuum. (Related: Tentacled, Carnivorous Plants Catapult Prey Into Traps.”)

Only the pitfall traps Nepenthes and Sarracenia and the snap trap Dionaea muscipula generated the distinct blue emissions, which turned out to be important to the plants’ survival. For instance, when scientists blacked out the ultraviolet light, the predators were less likely to attract insects. (Also see “Spiders, Carnivorous Plants Compete for Food—A First.”)

 

pitcher plant picture

The pitcher plant Nepenthes khasiana is seen in white light (left) and ultraviolet. Photograph courtesy Rajani Kurup, Anil J. Johnson, Sreethu Sankar, and Sabulal Baby

 

Though the research is incomplete, Baby also suspects that small animals like tree shrews and rats can also see the blue hue, enticing them to drink the plants’ sweet nectar. In the process, these animals drop fecal matter inside the plant, which becomes another good source of nutrients.

“The fluorescents are a very important attractant of insects, arthropods, and small animals,” he said.

Go With the Glow

Pitfall traps and snap traps aren’t the only plants to use ultraviolet frequencies. There are many species whose molecular makeup give them the ability to glow, said Howard Berg, a plant-cell biologist and the director of the Integrated Microscopy facility at the Donald Danforth Plant Science Center in Missouri.

“They have a chemical structure called conjugated double bond, and they have the ability to absorb light and re-emit it,” he said.

pitcher plant fluids picture

Fluids from a pitcher plant in the Nepenthes species fluoresce. Photograph courtesy Rajani Kurup, Anil J. Johnson, Sreethu Sankar, and Sabulal Baby

 

Berg added that the finding may even aid in future breakthroughs. Fluorescent jellyfish proteins are attached to specific markers, allowing researchers to study, for example, how cancer cells spread. The carnivorous plant’s glowing cells could potentially provide a new tracking method.

“It’s like a luggage tag,” Berg said. “You can use that as a locator. It’s really cool.”

What’s more likely, though, is the development of the ultimate bug zapper, study author Baby said.

The ultraviolet glow could work in tandem with an electric current to zap unsuspecting insects. The future of pest control—just go with the glow.

Comments

  1. PFC
    India
    December 17, 2013, 6:52 pm

    Mostly, insects are red-blind, so these blue emissions (in UV) are very significant.

  2. BIJU DHARMAPALAN
    INDIA
    April 12, 2013, 1:58 pm

    Dr Sabulal and his team of dedicated researchers have reminded us the old dictum ” chance favours only the prepared mind” . Even though many scientsits have looked upon the various aspects of Pitcher plant no body tried to analyze the mechanism of light intensity and metabolite production. As Dr Sabulal always mention in meetings that the idea strike them accidently during an experimental procedure of analyzing compounds using UV irradiation. Its also shows the success of working as a team even in a small lab

  3. Ryan Fisher
    United States
    April 8, 2013, 10:01 pm

    @ Laurie

    Nonsense – they’re not discredited in the least. The term ‘carnivorous’ is and has long been not only commonly but factually applicable. Both Venus Flytraps and Tropical Pitcher Plants have been known to capture and digest small mammals (although I believe in the case of Dionea, the traps often rot as a result).

  4. beaca
    March 6, 2013, 5:04 pm

    omg mah face lik dis : – -
    o

  5. beaca
    March 6, 2013, 5:02 pm

    dats tots cray! omg lik who new?!

  6. beaca
    March 6, 2013, 5:01 pm

    dats tots cray! omg lik who new

  7. Laurie Sheldon
    March 3, 2013, 10:59 pm

    They are INSECTIVOROUS, not CARNIVOROUS. There IS a difference. It discredits your article to call them anything to the contrary.

  8. lhet
    Philippines
    March 1, 2013, 12:14 am

    God is really exist! We can see Him, by all the things He created. And this amazing plants is just one of those…

  9. Erika
    February 28, 2013, 9:09 pm

    Brilliant! Reminds me of bio-luminescent plankton in lagoons in Puerto Rico, etc…

  10. 박근화
    korea
    February 28, 2013, 8:12 pm

    wow .I’m like this

  11. SHEJEE MATHEW
    February 28, 2013, 10:17 am

    Here are two recent studies in Nature and PNAS for the comments by Peter Cavan.

    Gronquist M, et al. (2001) Attractive and defensive functions of the ultraviolet pigments of a flower (Hypericum calycinum). Proc Natl Acad Sci USA 98:13745-13750.
    Gandia-Herrero F, Garcia-Carmona F, Escribano J. Botany: floral fluorescence effect. Nature 2005 437(7057): 334.

    These papers strongly indicate the ‘fluorescence effect’ in other contexts. I think, both papers reflect on relatively low levels of emissions (compared to this case).
    Again, is it not logical to think that these emissions from prey traps have an effect on ‘nocturnal capture rates’ and also on ‘mutualistic interactions with certain mammals’?

    Shejee

  12. Gary Hannan
    United States
    February 27, 2013, 11:12 pm

    I agree with Peter Kevan, and he should know. I have not yet read the article, but there seems to be an issue of confusing “emission” of UV light and fluorescence in the presence of UV light, the latter being absorption of UV and emission of longer wavelengths (rather inefficiently). Glowing blue in the presence of strong UV light does not translate directly into what the plants would look like to an animal capable of seeing into the UV region of the spectrum

  13. Daryl
    USA
    February 27, 2013, 9:57 pm

    Very interesting. Great work! Thanks for the story Mollie. Also, it’s too bad Angie can’t express her belief as it relates to this story without receiving all the sarcasm. Grow up people.

  14. Evgeniy
    Russia
    February 27, 2013, 11:27 am

    This is really interesting! I suppose carnivorous plants are very mysterious objects of nature. Their capability of glowing to attract of prey is new (i didn’t know about it up to this discovery)

  15. Peter Kevan
    Canada
    February 27, 2013, 10:45 am

    I do not want to be a wet blanket on this interesting discovery of fluorescence from the lips of Nepethes pichers, but must point out several issues that cast some doubt on the significance of this finding.
    1) The amount of UV available to be fluoresced in natural light at night is very small. It is not a strong component of natural daylight.
    2) Fluourescence is not an efficient means of “transferring” photons from a short wavelength to a longer wavelength (less than 25% or so).
    Thus, the fluorescence is taking light (UV) where its is already scarce naturally in the insect visible spectrum and translating into light that is already much more intense (bluish) in the natural spectrum where it is then combined with other reflexions (yellow and green) that are quite strong. It would seem that the combined effects may not make the colour locus of the lips of Nepethes pichers very different from what the locus would be without flourescence. The same issues have arisen before with respect to UV light and fluorescence by almond nectar (see reference to Thorp and response by Kevan in Science (some years ago), and the significance of fluorescence under UV of the exoskeletons of scorpions.

  16. LisF
    USA
    February 27, 2013, 9:52 am

    They found Pandora!

  17. Christian Duerig
    Bern, Switzerland
    February 27, 2013, 7:44 am

    I am amazed about the findings of the actual researchers. What I have learned 50 years ago is becoming in most cases obsolete. Only the Math withstands time. The most impressing are the findings of John Horton Conway, Jack Szostak and Shinya Yamanaka. Thank You very much for your contribution and do not forget You Tube to informe the world by video. Crigs

  18. Nikita
    Estonia
    February 27, 2013, 6:59 am

    To Angie

    I think.

  19. Tim
    Aus
    February 27, 2013, 1:48 am

    Come on Angie

  20. David
    United States
    February 26, 2013, 10:51 pm

    @Angie I don’t.

  21. New Yorker
    USA
    February 26, 2013, 6:34 pm

    Fantastic. I once read that some flowers emit uv to further attract bees. What a find from India about Pitcher Plants!

  22. darran
    uk
    February 26, 2013, 6:26 pm

    Electric bug zappers have used uv to attracted insects to their death for decades haven’t they?…….. Glowing plants, cool, now Avatar doesn’t seem so far fetched after all
    Darran

  23. cam
    usa
    February 26, 2013, 5:03 pm

    Really angie? a post about glowing plants and you bring up god?

  24. Nate Whilk
    February 26, 2013, 3:01 pm

    “What’s more likely, though, is the development of the ultimate bug zapper, study author Baby said. The ultraviolet glow could work in tandem with an electric current to zap unsuspecting insects. The future of pest control—just go with the glow.”

    There are already UV bug zappers out there (and they attract all types of insects, not just pests). What exactly would make this development lead to an “ultimate” bug zapper?

  25. Sean
    United States
    February 26, 2013, 1:04 pm

    It is truly humbling to see the beauty and complexity of nature, and confusing to realize how most would pave it over for a few bucks.

  26. mohammad yusuf nowbuth
    usa
    February 26, 2013, 12:59 pm

    wow its impressive

  27. Joby S Titus
    Doha,QATAR
    February 26, 2013, 12:37 pm

    Amazing fact ..Hearty congrats to the team

  28. Katelyn van Dyk
    Oregon
    February 26, 2013, 12:27 pm

    Wow! So interesting!

  29. sreethu sankar
    India
    February 26, 2013, 12:27 pm

    thkz to alll

  30. linson thomas
    India
    February 26, 2013, 9:47 am

    Superb work..

  31. Siby Kottavila
    Dubai
    February 26, 2013, 5:49 am

    Its a great news .Highly appreciating the efforts of Dr.Sabulal Baby & his team of Jawaharlal Nehru Tropical Botanic Garden and Research Institute in India, for bringing out such an amazing fact in carnivorous plants.

    Thanks to NATIONAL GEOGRAPHIC for the report

  32. SHEJEE MATHEW
    India
    February 26, 2013, 5:35 am

    This is a really new discovery on carnivorous plants – prey capture. Very good.

    Shejee

  33. Angie
    Australia
    February 26, 2013, 1:40 am

    Who really thinks there is no God?