The First Genus (Alphabetically)

Photo by Eric in SF licensed under CC BY-SA 3.0

One thing I love about orchids is that they are so diverse. One could spend their entire life studying these plants and never run out of surprises. Every time I sit down with an orchid topic in mind, I end up going down a rabbit hole of immeasurable depth. I love this because I always end up learning new and interesting facts. For instance, I only recently learned that there is a genus of orchids that has been given the unbelievably complex name of Aa.

No, that is not an abbreviation. The genus was literally named Aa. As far as I have been able to tell, it is pronounced “ah” rather than “ay,” but if any linguists are reading this and beg to differ, please chime in! Regardless, I was floored by this silly exercise in plant naming and had to learn more. I had never heard of this genus before and figured that it was so obscure that it probably contained, at most, only a small handful of species. This assumption was wrong.

Aa maderoi. Photo by Dr. Alexey Yakovlev licensed under CC BY-SA 2.0

Though by no means massive, the genus Aa contains at least 25 recognized species. A quick search of the literature even turned up a few relatively recent papers describing new species. Apparently we have a ways to go in understanding their diversity. Nonetheless, this is an interesting and pretty genus of orchids.

From what I gather, Aa are most often found growing at high elevations in the Andes, though at least one species is native to mountainous areas of Costa Rica. They are terrestrial orchids that prefer cooler temperatures and fairly moist soil. Some species are said to only be found in close proximity to mountain streams. Some of the defining features of the genus are a tall inflorescence jam packed with tiny inconspicuous, greenish-white flowers. The flowers are surrounded by semi-transparent sheaths that are surprisingly showy. All in all, they kind of remind me of a mix between Spiranthes and Goodyera.

Close up of an inflorescence of Aa maderoi showing the small, white flowers and large, semi-transparent sheaths. Photo by Dr. Alexey Yakovlev licensed under CC BY-SA 2.0

But what about the name? Why in the world was this genus given such a strange and abrupt moniker? The answer seems to be the silliest option I could think of: to be first. This genus was originally described in 1845 by German botanist Heinrich Gustav Reichenbach who recognized two species within the genus Altensteinia to be distinct enough to warrant their own genus.

According to most sources I could find, he coined this new genus Aa so that it would appear first on all taxonomic lists. There is at least one other report that the name was given in honor of a man by the name of Pieter van der Aa, but apparently this is “highly” disputed. However, all of this should be taken with a grain of salt. Though I can find plenty of literature describing various species within the genus, I could turn up no actual literature on the naming of the genus itself. All I could find is what has been repeated (almost verbatim) from Wikipedia.

So, there you have it. Not only does the genus Aa exist, it is still top of the list of all plant genera. If that truly was the goal Heinrich Gustav Reichenbach was aiming for, he certainly has succeeded!

Photos via Wikimedia Commons

Further Reading: [1]

Drunken Pollinators & Chemical Trickery: Musings on the Complex Floral Chemistry of a Generalist Orchid

There was a time when I thought that all orchids were finicky botanical jewels, destined to perish at the slightest disturbance. Certainly many species fit this description to some degree, but more often these days I am appreciating the role disturbance can play in maintaining many orchid populations. Seeing various genera like Platanthera or Goodyera thriving along trails and old dirt roads, lawn orchids (Zeuxine strateumatica) growing in manicured lawns, or even various Pleurothallids growing on water pipes in the mountains of Panama has opened my eyes to the diversity of ecological strategies this massive family of flowering plants employs.

Of the examples mentioned above, none can hold a candle to the hardiness of the broad-leaved helleborine orchid (Epipactis helleborine) when it comes to thriving in disturbed habitats. Originally native throughout much of Europe, North Africa, and Asia, this strangely beautiful orchid can now be found growing throughout many temperate and sub-tropical regions of the world. Indeed, this is one species of orchid that has greatly benefited from human disturbance. In fact, I more often see this orchid growing in and around cities and along roadsides than I do in natural settings (not to say it isn’t there too). In many areas here in North America, the broad-leaved helleborine orchid has gone from a naturalized oddity into a full blown invasive.

Much of its success in conquering new and often highly disturbed territory has to do with its relationship with mycorrhizal fungi. Like all orchids, the broad-leaved helleborine orchid requires fungi for germination and growth, relying on the symbiotic relationship into maturity. Without mycorrhizal fungi, these orchids could not survive. However, while many orchids seem to be picky about the fungi they will partner with, the broad-leaved helleborine is something of a generalist in this regard. At least one study in Europe was able to demonstrate that over 60 distinct groups of mycorrhizal fungi were able to partner with this orchid. By opening itself up to a wider variety of fungal partners, the broad-leaved helleborine orchid is able to live in places where pickier orchids cannot.

Another key to this orchids success has to do with its pollination strategy. Here again we see that being a generalist comes with serious advantages. Though wasps are thought to be the most effective pollinators, myriad other insects from various kinds of flies to beetles and butterflies will visit these blooms. How is it that this orchid has become to appealing to such a wide variety of insects? The answer is chemistry.

The broad-leaved helleborine orchid is something of a skilled chemist. When scientists analyzed the nectar produced in the cup-shaped lip of the flower, they found a diverse array of chemicals, many of which lend to some incredible insect interactions. For starters, highly scented compounds such as vanillin (the compound responsible for the vanilla scent and flavor of Vanilla orchids) are produced in the nectar, which certainly attracts many different kinds of insects. There is also evidence of some floral mimicry going on as well.

Scientists found a group of chemicals called kairomones in broad-leaved helleborine nectar, which are very similar to aphid alarm pheromones. When released by aphids, they warn nearby kin that predators are in the area. In one sense, the production of these compounds in the nectar may serve to ward off aphids looking for a new place to feed. However, these chemicals also appear to function as pollinator attractants. For aphid predators like hoverflies, these pheromones act as a dinner bell, signalling good egg laying sites for gravid female hoverflies whose larvae gorge themselves on aphids as they grow. It just so happens that hoverflies also serve as important pollinators for the broad-leaved helleborine orchid.

A series of compounds broadly classified as green-leaf volatiles were found in the nectar as well. Many plants produce these compounds when their leaves are damaged by insect feeding. Like the aphid example above, green-leaf volatiles signal to nearby predatory insects that plump herbivores are nearby. For instance, when the caterpillars of the cabbage white butterfly feed on cabbage plants, green-leaf volatiles attract wasps, which quickly set to work eating the caterpillars, relieving the plant of its herbivores in the process. As previously mentioned, wasps are thought to be the main pollinators for this orchid so attracting them makes sense. However, attracting pollinators using chemical trickery can be risky. What happens when a pollinator shows up and realizes there is no plump aphid or caterpillar to eat?

The answer to this comes from a series of other compounds produced in this orchid’s nectar. Few insects will turn down a sugary meal, and indeed, many visitors end up sipping some broad-leaved helleborine nectar. Sit back and watch and it won’t take long to realize that these insects appear to quickly become intoxicated. Their behavior becomes sluggish and they generally bumble around the flowers until they sober up and fly off. This is not happenstance. This orchid actively gets its pollinators wasted, but how?

Along with the chemicals we already touched on, scientists have also found a plethora of narcotics in broad-leaved helleborine nectar. These include various types of alcohols and even chemicals similar to that of opioids like Oxycodone. Now, some have argued that the alcohols are not the product of the plant but rather the result of fermentation by yeasts and bacteria living within the nectar. However, the presence of different antimicrobial compounds coupled with the sheer concentrations of alcohols within the nectar appear to discount this hypothesis and point to the plant as the sole creator. Nonetheless, after a few sips of this narcotic concoction, insects like wasps and flies spend a lot more time at each flower than they would if they remained sober the whole time. This has led to the suggestion that narcotics help improve the likelihood of successful pollination.

Indeed, the broad-leaved helleborine orchid seems to have no issues with sex. Most plants produce a bountiful crop of seed-laden fruits each summer. In fact, it has been found that plants growing in areas of high human disturbance tend to set more seed than plants growing in natural areas. Scientists suggest this is due to the wide variety of pollinators that are attracted to the complex nectar. Human environments like cities tend to have a different and sometimes more varied suite of insects than more rural areas, meaning there are more opportunities for run ins with potential pollinators.

The broad-leaved helleborine orchid stands as an example of the complexities of the orchid family. Few orchids are as generalist in their ecology as this species. Its ability to grow where others can’t while taking advantage of a variety of pollinators has lent to the extreme success of this species world wide.

Photo Credit: [1]

Further Reading: [1] [2] [3] [4] [5] [6]

The Heartleaf Twayblade Orchid

Photo by Cptcv licensed under CC BY-ND 2.0.

The heartleaf twayblade is truly a sight for sore eyes.... that is, if you can find it. This diminutive orchid stands no more than 30 cm tall when in bloom and, for much of its life, exists as a single pair of tiny, heart-shaped leaves. Finding this species in bloom has been one of the major highlights of the last few years of botanizing. Getting to see it up close makes me wonder how many times I may have passed it over completely.

A closeup examination of the flowers will reveal what looks like tiny little humanoids. Indeed, the flowers are complex little structures. Tiny trigger hairs located at the base of the pollinia squirt glue on the back of visiting insects, which affixes the pollen sacs or pollinia. One to two days after the pollinia have been removed the stigmas become receptive to pollen. Though this orchid can self fertilize, differential ripening of sexual parts like this helps ensure cross pollination between different individuals.

With flowers so small, it is a wonder that insects can even find them. As it turns out, the flowers emit a foul smelling odor, though one would be hard pressed to detect it having to bend down so close to the forest floor. This attracts a wide variety of small insects like wasps and flies. The most common visitors, however, are fungus gnats. Ever abundant in the moist duff of the forest, these tiny dipterids offer plenty of opportunity for pollination. The orchid even sweetens the deal a bit by producing a small amount of nectar.

Being so small it is quite easy to overlook this plant. One must put in a bit of searching to find them. Their tiny size also means that they are often under-represented in conservation efforts as well. Entire populations can exist in only a few square meters of forest and thus are quite sensitive to disturbance. Timber harvesting and sprawl represent the largest threats the this species but luckily it has a surprisingly large geographic distribution. Still, keep an eye out for this lovely little species. They may be hard to find but they are well worth the effort!

Photo Credit: [1]

Further Reading: [1] [2] [3]

The Deceptive Ways of the Calypso Orchid

Photo by Murray Foubister licensed under CC BY-ND 2.0.

Behold the Calypso orchid, Calypso bulbosa. This circumboreal orchid exists as a single leaf lying among the litter of dense conifer forests. They go virtually unnoticed for most of the year until it comes time to flower.

In early spring, the extravagant blooms open up and await the arrival of bumblebees. Calypsos go to great lengths to attract bumblebees. The flower is said to have a sweet scent. Also, the lip sports small, yellow, hair-like protrusions that are believed to mimic anthers covered in pollen. Finally, within the pouch formed by the lip are two false nectar spurs. All of these are a ruse. The Calypso offers no actual rewards to visiting bumblebees.

Not just any bumblebee will do. For the ruse to work, it requires freshly emerged workers that are naive to the orchid’s deception. Bumblebees are not mindless animals. They quickly learn which flowers are worth visiting and which are not. Because of this, the Calypso has only short window of time in which bumblebees in the vicinity are likely to fall for its tricks. As a result, pollination rates are often very low for this orchid.

The most interesting aspect of all of this is that the so-called "male function" of the flower - pollinia removal - is more likely to occur than the "female function" - pollen deposition. The reason for this makes a lot of sense in context; male function requires a bumblebee to be fooled only once whereas female function requires a bumblebee to be fooled at least twice.

The caveat to all of this deception is that a single Calypso, like all other orchids, can produce tens of thousands of seeds. Each orchid therefore has tens of thousands of potential propagules to replace itself in the next generation. Despite that fact, the Calypso orchid is on the decline. Habitat destruction, poaching, deer, and invasive species are taking their toll. If you care about orchids like the Calypso, please consider supporting organizations like the North American Orchid Conservation Center.

Photo by Murray Foubister licensed under CC BY-ND 2.0.

Photo Credit: [1] [2]

Further Reading: [1] [2] [3] [4]

What an orchid that smells like rotting meat can tell us about carrion flies

Satyrium pumilum Photo by Bernd Haynold licensed by CC BY-SA 3.0

Orchids are really good at tricking pollinators. Take, for instance, this strange looking orchid from South Africa. Satyrium pumilum is probably obscure to most of us but it is doing fascinating things to ensure its own reproductive success. This orchid both smells and kind of looks like rotting meat, which is how it attracts its pollinators.

It is a bit strange to think of orchids living in arid climates like those found in South Africa but this family is defined by exceptions. That is not to say that Satyrium pumilum is a desert plant. To find this orchid, you must look in special microclimates where water sticks around long enough to support its growth. Populations of S. pumilum are most often found clustered near small streams or hidden under bushes throughout the western half of the greater Cape Floristic Region.

Satyrium pumilum blooms from the beginning of September until late October. As is typical in the orchid family, S. pumilum produces rather intricate flowers. Whereas the sepals are decked out in various shades of green, the interior of the flower is blood red in color. Also, unlike many of its cousins, S. pumilum doesn’t throw its flowers up on a tall stalk for all the world to see. Instead, its flowers open up at ground level and give off an unpleasant smell of rotting meat.

This is where pollinators enter into the picture. It has been found that carrion flies are the preferred pollinator for S. pumilum. By producing flowers at ground level that both look and smell like rotting meat, the plants are primed to attract these flies. The plants are tapping into the flies’ reproductive habits, a biological imperative so strong that they simply do not evolve a means of discriminating a rotting corpse from a flower that smells like one. This is the trick. Flies land on the flower thinking they have found a meal and a place to lay their eggs. They go through the motions as expected and pick up or deposit pollen in the process. Unfortunately for the flies, their offspring are doomed. There is not food to be found in these flowers.

What is most remarkable about the reproductive ecology of S. pumilum is that not just any type of fly will do. It appears that only a specific subset of flies actually visit the flowers and act as effective pollinators. Amazingly, this provides insights into some long-running hypotheses regarding carrion fly ecology.

(A) The habitat of S. pumilum (B) Satyrium pumilum in situ (scale bar = 1 cm). (C–E) Pollination sequence of a S. pumilum flower by a sarcophagid fly in an arena (scale bar for all three photos = 0·5 cm); (C) the fly carrying five pollinaria from other S. pumilum flowers enters an unpollinated flower (D) as the fly moves deeper into the flower towards the right-hand spur, it presses an attached pollinium against the stigma, and its thorax against the right-hand viscidium; (E) as it leaves the flower, the fly has deposited two massulae on the stigma (1), and removed a pollinarium (2) – it now carries six pollinaria. [SOURCE]

Apparently there has been a lot of debate in the fly community over why we see so many different species of carrion flies. Rotting meat is rotting meat, right? Probably not, actually. Fly ecologists have comes up with a few hypotheses involving niche segregation among carrion flies to explain their diversity on the landscape. Some believe that flies separate themselves out in time, with different species hatching out and breeding at different times of the year. Others have suggested that carrion flies separate themselves by specializing on carrion at different stages of decay. Still others have suggested that some flies specialize on large pieces of carrion whereas others prefer smaller pieces.

By studying the types of flies visiting the flowers of S. pumilum researchers did find evidence of niche segregation based on carrion size. It turns out that S. pumilum is exclusively pollinated by a group of flies known as sarcophagid carrion flies. These flies were regularly observed with orchid pollen sacs stuck to their backs and plants seemed to only set seed after they had been visited by members of this group. So, what is it about these flowers that makes them so specific to this group of flies?

The answer lies both in their size as well as the amount of scent they produce. It is likely that the quantity of scent compounds produced by S. pumilum most closely mimics that of smaller rotting corpses. The types of flies that visited these blooms were mostly females of species that lay relatively few eggs compared to other carrion flies. It could very well be that the smaller brood size of these flies allows them to effectively utilize smaller bits of carrion than other, more fecund species of fly. To date, this is some of the best evidence in support of the idea that flies avoid competition among different species by segregating out their feeding and reproductive niches.

Rotting meat smells are not uncommon in the plant world. Even within the home range of S. pumilum, there are other plants produce flowers that smell like carrion as well. It would be extremely interesting to look at what kinds of flies visit other carrion flowers and in what numbers. Like I mentioned earlier, reproductive is such a major part of any organisms life that it may simply be too costly for carrion flies to evolve a means of discriminating real and fake breeding sites. It is amazing to think of what we gain from trying to understand the reproductive biology of a small, obscure orchid growing tucked away in arid regions of South Africa.

Photo Credits: [1] [2]

Further Reading: [1]

Mutant Orchids Have a lot to Teach Us About Parasitic Plants

A) Albino and (B) green individual of Goodyera velutina.

The botanical world is synonymous with the idea of photosynthesis. Plants take in carbon dioxide and water and utilize light to make their own food. However, not all plants make a living this way. There are many different species of plants that have evolved a parasitic lifestyle to one degree or another. Some of my favorites are those that parasitize mycorrhizal fungi. We call these plants “mycoheterotrophs” and they are fascinating to say the least. Orchids are especially prone to this strategy, with over 1% of all known species having completely lost the ability to photosynthesize.

Our knowledge of the mycoheterotrophic strategy is fragmentary at best. We still don’t fully understand things like how the plants obtain what they need from the fungus nor how they are able to maintain their parasitic lifestyle without the fungus catching on and rejecting the one-sided partnership. This is not to say we know nothing. In fact, as technologies advance, we are unlocking at least some of the mysteries of mycoheterotrophic plants. Some of the best advances come from studying mutant, albino orchids. To understand how, we have to take a closer look at the “average” orchid lifestyle.

Orchids in general make great candidates for understanding the evolution of mycoheterotrophy because all of them start their lives as parasites. Orchids produce some of the smallest seeds in the plant kingdom and without the help of mycorrhizal fungi, they would never be able to germinate. For much of their early life, orchids rely on fungi to provide them with both their mineral and carbohydrate needs. Only after the orchids are large enough to grow leaves will most of them start to give back to their fungal partners in the form of carbohydrates generated from photosynthesis.

Still, many orchids never fully let go of this parasitic lifestyle. This is especially true for orchids living under dense forest canopies. With light in limited supply, many orchids adopt a mixotrophic lifestyle. Essentially this means that although they actively photosynthesize, they nonetheless rely on fungi to provide them with both carbohydrates and minerals. Mixotrphy is likely the most wide-spread orchid strategy and it has been hypothesized that it is also the first step along the path to becoming fully parasitic. This is where the mutant orchids enter the equation.

(A) Albino and (B) green individuals of Epipactis helleborine

Every once in a while, some orchids will germinate and grow into albino versions of their species. Without the ability to produce chlorophyll, these mutants should be destined for a quick death. Such is not the case for many of these orchids. Albino orchids often go on to live full lives, growing and flowering just like their photosynthetic progenitors. Although they do exhibit signs of reduced fitness, the fact that they are able to live at all brings up a lot of questions ready for science to tackle.

Recent investigations into the lives of these albino mutants has revealed some interesting insights into how mycoheterotrophy may have evolved in the first place. By studying the fungal partners of both healthy plants and the albinos, researchers have been able to demonstrate that albinos are doing things a bit differently than their photosynthetic parents. Using isotopes of carbon and nitrogen, scientists are discovering that the albinos have switched their interaction with the fungi in such a way that they more resemble fully mycoheterotrophic orchid species. This is done despite the fact that both albinos and their fully functional parents associate with the same guild of mycorrhizal fungi.

Another interesting difference between albinos and their photosynthetic parents is the fact that the genes involved both antioxidant metabolism and metabolite transfer (mainly carbon in this case) were more active in the albinos than they were in functioning plants. The uptick in gene functioning related to antioxidant metabolism suggests that the mutant plants are undergoing greater oxidative stress than their functional parents. This may have something to do with how the albinos are able to obtain nutrients from their fungal partners. It is thought that mycoheterotrophs actively digest parts of the fungi, which allows them to access the carbon and minerals they need to survive. This process exposes their cells to reactive oxygen compounds that can be very damaging. Antioxidants would help to reduce such damage.

The uptick in genes associated with metabolite transfer was more surprising because it suggests that despite being parasites, the plants are actively transferring substances back to the fungi. It has long been assumed that mycoheterotrophy was a one way street, with fungi transferring nutrients to plants only. These genes now suggest that, at least in some species, such transfer is a two-way street. The exact nature of this two-way transfer remains a mystery and certainly brings up many more questions that must be asked before we can better understand this relationship.

All of this is not to say that such albino mutants are fruitful “next steps” in the evolution of these species. Far from it, in fact. Two things that most albino orchid variants have in common is the fact that they are rare and, of those that have been studied, produce far fewer seeds. There are a lot of anatomical and physiological differences between true mycoheterotrophic species and albino variants and it appears that without those anatomical adaptations, the albinos are a lot less fit than their photosynthetic parents. As authors Selosse and Roy put it:

“non-chlorophyllous variants are likely to represent unique snapshots of failed transitions from mixotrophy to mycoheterotrophy. They are ecological equivalents to mutants in genetics, that is, their dysfunctions might suggest what makes mycoheterotrophy successful. Although their determinism remains unknown, they offer fascinating models for comparing the physiology of mixo- and mycoheterotrophs within similar genetic backgrounds.”

Mutants are strange indeed but with the right kinds of questions and approaches, they have a lot to teach us about ecology, evolution, and life at large.

Photo Credits: [1] [2]

Further Reading: [1] [2] [3]

Meeting the Elusive Three Birds Orchid

Rare but locally abundant has to be the only proper way of describing the distribution of this peculiar little orchid. I have known about the three birds orchid (Triphora trianthophoros) for some time now. I'm generally not a jealous person but I did find myself quite envious of those who have encountered it. Even with ample herbarium records I simply could not seem to locate any individuals of this species.

The best advice for finding it that I was ever given was to not go looking for it. This secretive little plant is something you almost have to stumble upon. And stumble I did. While surveying some vegetation plots that I had combed over all summer back in 2016 I noticed something new poking up. The slender red stalks had tiny green leaves and elongated flower buds at the top. I knew instantly that this could only mean one thing - I had finally found some three birds.

Both the common and scientific name hint at the fact that these plants are often seen with three flowers. This is not a rule by any means as plants can be found with as few as one flower or as many as 10. Regardless of the amount, finding them is only part of the battle. The other challenge is to catch them in bloom.

The secretive nature of this orchid has led to some interesting tips on how to get your timing right. Some say to check a known population after the first big rain of August. Another more pervasive tip claims that one must take to the forest after nighttime temperatures take a sudden dip. Despite this entertaining advice, it would seem that you just have to be in the right place at the right time.

What is known about the flowering habits of the three birds orchid is that populations tend to flower in unison. The buds all develop to a certain point and stop. They will sit and wait for the right conditions (whatever they might be) to arise. Once that crucial condition is hit, they rapidly bloom en masse. This is a wonderful strategy for a flowering plant that lives tucked away on the shady forest floor.

Concealed among the forest debris, one or two flowers wouldn't get much attention. Hundreds of bright white and pink flowers, however, certainly do! Juxtaposed against the shade of the forest, these little orchids almost glow like little neon signs. Despite this mass effort, it has been found that pollination rates are usually very low. Instead, this orchid most often reproduces vegetatively by budding off tiny plantlets from the main root stock. Because of this, it is not uncommon to find literally hundreds of plants of various sizes clustered together within inches of each other. This is an impressive sight to behold.... again, if you are lucky enough to find it.

Like many of its orchid cousins, this species is no stranger to the disappearing act. Because they rely so heavily on mycorrhizal fungi for their nutrient needs, exhausted plants will often go dormant under the soil for years until they gain enough energy to produce stems, leaves, and flowers again. If you come across the three birds orchid during your travels, do yourself a favor and take some time to relish the moment. It may be a long time before you ever see them again.

Further Reading: [1] [2]

The Round Leaved Orchid

In the northern temperate regions of North America, late June marks the beginning of what I like to call orchid season. If you're lucky you may stumble across one of these rare beauties in full bloom. Their diversity in shape and size are mainly a result of the intricate evolutionary relationships they have formed with their pollinators. I spend much of my time botanizing trying to locate and photograph these botanical curiosities and any time I get to meet a new species is a very special time indeed. 

Take the round leaved orchid (Platanthera orbiculata) for example. For years I have only known this species as two round leaves that are slightly reminiscent of the phaleanopsis orchids you see for sale in nurseries and grocery stores. The leaves can be quite large too. With their glossy appearance, they are the easiest way to locate this plant.

When conditions are right and the plants have enough stored energy they will begin to flower. Rising from the middle of the pair of leaves is a decent sized inflorescence loaded with greenish white flowers. The flowers are interesting structures. Not particularly colorful, they have a long white lip and considerable green nectar spurs. There are said to be two varieties of this species, each being characterized by the length of the nectar spur. Unlike many orchids that offer no reward to pollinators, P. orbiculata produces nectar. The flowers are pollinated by noctuid moths, which is probably why they are white in color. Whereas most lepidopteran pollinated orchid attach their pollinia to the proboscis of the butterfly or moth, P. orbiculata attaches its pollinia to the eyes of visiting moths. 

If this isn't strange enough, the pollinia themselves have some of their own intriguing adaptations. Visiting moths take a certain amount of time to successfully access the nectar from the nectar spur. If the plant is to avoid wasting precious pollen on itself, then it must find a way to delay this process. The pollinia are the solution to this. When first attached to the eyes, the pollinia stick straight up. This keeps them away from the female parts of the plant as the moth feeds. Only after enough time has elapsed will the stalks of the pollinia begin to bend forward. At this point the moth will hopefully have moved on to the flowers of an unrelated individual. Pointing straight forward, they are now perfectly positioned to transfer pollen. 

Like all orchids, P. orbiculata relies on specialized mycorrhizal fungi for germination and survival. At the beginning of its life, P. orbiculata relies solely on the fungi for sustenance. Once it has enough energy to produce leaves it will repay the fungi by providing carbohydrates. However, the relationship is not over at this point. Every spring, P. orbiculata produces a new set of leaves as well as a whole new root system. The fungi supply a lot of energy for this process and if the plant is disturbed (ie. dug up by greedy poachers) or browsed upon, it is likely that it will not recover from the stress and it will die. The mycorrhizal fungi it relies on live on rotting wood so finding well rotted logs is a good place to start searching for this species. With declining populations throughout much of its range, it is important to remember to enjoy it where it grows. Leave wild orchids in the wild!

Further Reading: [1] [2] [3] [4]

The Upside Down World of Orchid Flowers

Did you know that most orchid flowers you see are actually blooming upside down? That's right, referred to as "resupination," the lower lip of many orchid flowers is actually the top petal and, as the flower develops inside the bud, the whole structure makes a 180° rotation. How and why does this happen?

The lip of an orchid flower usually serves to attract pollinators as well as function as a landing pad for them. The flower of an orchid is an incredibly complex organ with an intriguing evolutionary history. Basically, the lip is the most derived structure on the flower and, in most cases, it is the most important structure in initiating pollination.

The non-resupinate flowers of the grass pink (Calopogon tuberosus) showing the lip on top.

As an orchid flower bud develops, it begins to exhibit gravitropic tendencies, meaning it responds to the pull of gravity. By removing specific floral organs like the column and pollinia, researchers found that they produce special hormones called auxins that tell the developing bud to begin the process of resupination. The ovary starts to twist, causing the flower to stand on its head.

Not all orchids exhibit resupinate flowers. Grass pinks (Calopogon tuberosus) famously bloom with the lip pointing up as it does in the early stages of bud development. It is an interesting mechanism and serves to demonstrate the stepwise tendencies that the forces of natural selection and evolution can manifest. But why does it occur at all? What is the evolutionary advantage of resupinate flowers?

Not only are Dracula flowers resupinate, many species also face them towards the ground.

The most likely answer to this biological twist is that, for orchids, resupination places the lip in such a way that facilitates pollination by whatever the flowers are attracting. For many orchids, this means providing an elaborate landing strip in the form of the lip. For the grass pinks, which operate by slamming visiting bees downward onto the column to achieve pollination, placing the lip at the top makes more mechanical sense. When a bee visits the upward pointing lip thinking it will find a pollen-rich meal, the lip bend at the base like a hinge. Anything goes in evolution provided the genes are present for selection to act upon and nowhere is this fact more beautifully illustrated than in orchids.

Further Reading: [1] [2] [3]

From Herbivore to Pollinator Thanks to a Parasitoid

In the Atlantic forests of Brazil resides a small orchid known scientifically as Dichaea cogniauxiana. Like most plant species, this orchid experiences plenty of pressure from herbivores. It faces rather intense pressures from two species of weevil in the genus Montella. These weevils are new to science and have yet been given full species status. What's more, they don't appear to eat the leaves of D. cogniauxiana. Instead, female weevils lay eggs in the developing fruits and the larvae hatch out and consume the seeds within. In other words, they treat the fruits like a nursery chamber.

This is where this relationship gets interesting. You see, the weevils themselves appear to take matters into their own hands. Instead of waiting to find already pollinated orchids, an event that can be exceedingly rare in these dense forests, these weevils go about pollinating the orchids themselves. Females have been observed picking up orchid pollinia and depositing the pollen onto the stigmas. In this way, they ensure that there will be developing fruits in which they can raise their young.

Left unchecked, the weevil larvae readily consume all of the developing seeds within the pod, an unfortunate blow to the reproductive efforts of this tiny orchid. However, the situation changes when parasitoid wasps enter the mix. The wasps are also looking for a place to rear their young but the wasp larvae do not eat orchid seeds. Instead, the wasps must find juicy weevil larvae in which to lay their eggs. When the wasp larvae hatch out, they eat the weevil larvae from the inside out and this is where things get really interesting.

The wasp larvae develop at a much faster rate than do the weevil larvae. As such, they kill the weevil long before it has a chance to eat all of the orchid seeds. By doing so, the wasp has effectively rescued the orchids reproductive effort. Over a five year period, researchers based out of the University of Campinas found that orchid fruits in which wasp larvae have killed off the weevil larvae produced nearly as many seeds as uninfected fruits. As such, the parasitoid wasps have made effective pollinators out of otherwise destructive herbivorous weevils.

The fact that a third party (in this case a parasitic wasp) can change a herbivore into an effective pollinator is quite remarkable to say the least. It reminds us just how little we know about the intricate ways in which species interact and form communities. The authors note that even though pollination in this case represents selfing and thus reduced genetic diversity, it nonetheless increases the reproductive success of an orchid that naturally experiences low pollination rates to begin with. In the hyper diverse and competitive world of Brazilian rainforests, even self-pollination cab be a boost for this orchid.

Photo Credits: [1] [2]

Further Reading: [1]

The Extraordinary Catasetum Orchids

Male Catasetum osculatum. Photo by Orchi licensed under CC BY-SA 3.0

Orchids, in general, have perfect flowers in that they contain both male and female organs. However, in a family this large, exceptions to the rules are always around the corner. Take, for instance, orchids in the genus Catasetum. With something like 166 described species, this genus is interesting in that individual plants produce either male or female flowers. What's more, the floral morphology of the individual sexes are so distinctly different from one another that some were originally described as distinct species. 

Female Catasetum osculatum. Photo by Valdison Aparecido Gil licensed under CC BY-SA 4.0

In fact, it was Charles Darwin himself that first worked out that plants of the different sexes were indeed the same species. The genus Catasetum enthralled Darwin and he was able to procure many specimens from his friends for study. Resolving the distinct floral morphology wasn't his only contribution to our understanding of these orchids, he also described their unique pollination mechanism. The details of this process are so bizarre that Darwin was actually ridiculed by some scientists of the time. Yet again, Darwin was right. 

Catasetum longifolium. Photo by Maarten Sepp licensed under CC BY-SA 4.0

If having individual male and female plants wasn't strange enough for these orchids, the mechanism by which pollination is achieved is quite explosive... literally. 

Catasetum orchids are pollinated by large Euglossine bees. Attracted to the male flowers by their alluring scent, the bees land on the lip and begin to probe the flower. Above the lip sits two hair-like structures. When a bee contacts these hairs, a structure containing sacs of pollen called a pollinia is launched downwards towards the bee. A sticky pad at the base ensures that once it hits the bee, it sticks tight. 

Male Catasetum flower in action. Taken from BBC's Kingdom of Plants.

Bees soon learn that the male flowers are rather unpleasant places to visit so they set off in search of a meal that doesn't pummel them. This is quite possibly why the flowers of the individual sexes look so different from one another. As the bees visit the female flowers, the pollen sacs on their back slip into a perfect groove and thus pollination is achieved. 

The uniqueness of this reproductive strategy has earned the Catasetum orchids a place in the spotlight among botanists and horticulturists alike. It begs the question, how is sex determined in these orchids? Is it genetic or are there certain environmental factors that push the plant in either direction? As it turns out, light availability may be one of the most important cues for sex determination in Catasetum. 

Photo by faatura licensed under CC BY-NC-ND 2.0

A paper published back in 1991 found that there were interesting patterns of sex ratios for at least one species of Catasetum. Female plants were found more often in younger forests whereas the ratios approached an even 1:1 in older forests. What the researchers found was that plants are more likely to produce female flowers under open canopies and male flowers under closed canopies. In this instance, younger forests are more open than older, more mature forests, which may explain the patterns they found in the wild. It is possible that, because seed production is such a costly endeavor for plants, individuals with access to more light are better suited for female status. 

Catasetum macrocarpum. Photo by maarten sepp licensed under CC BY-SA 2.0

Aside from their odd reproductive habits, the ecology of these plants is also quite fascinating. Found throughout the New World tropics, Catasetum orchids live as epiphytes on the limbs and trunks of trees. Living in the canopy like this can be stressful and these orchids have evolved accordingly. For starters, they are deciduous. Most of the habitats in which they occur experience a dry season. As the rains fade, the plants will drop their leaves, leaving behind a dense cluster of green pseudobulbs. These bulbous structures serve as energy and water stores that will fuel growth as soon as the rains return. 

Catasetum silvestre in situ. Photo by Antonio Garces licensed under CC BY-NC-ND 2.0

The canopy can also be low in vital nutrients like nitrogen and phosphorus. As is true for all orchids, Catasetum rely on an intimate partnership with special mychorrizal fungi to supplement these ingredients. Such partnerships are vital for germination and growth. However, the fungi that they partner with feed on dead wood, which is low in nitrogen. This has led to yet another intricate and highly specialized relationship for at least some members of this orchid genus. 

Photo by faatura licensed under CC BY-NC-ND 2.0

Mature Catasetum are often found growing right out of arboreal ant nests. Those that aren't will often house entire ant colonies inside their hollowed out pseudobulbs. This will sometimes even happen in a greenhouse setting, much to the chagrin of many orchid growers. The partnership with ants is twofold. In setting up shop within the orchid or around its roots, the ants provide the plant with a vital source of nitrogen in the form of feces and other waste products. At the same time, the ants will viciously attack anything that may threaten their nest. In doing so, they keep many potential herbivores at bay.  

Female Catasetum planiceps. Photo by sunoochi licensed under CC BY 2.0

To look upon a flowering Catasetum is quite remarkable. They truly are marvels of evolution and living proof that there seems to be no end to what orchids have done in the name of survival. Luckily for most of us, one doesn't have to travel to the jungles and scale a tree just to see one of these orchids up close. Their success in the horticultural trade means that most botanical gardens house at least a species or two. If and when you do encounter a Catasetum, do yourself a favor and take time to admire it in all of its glory. You will be happy that you did. 

Photo Credits: [1] [2] [3] [4] [5] [6] [7] [8] [9] 

Further Reading: [1] [2] [3] [4] [5]

In Search of the Orange Fringed Orchid

In Defense of Plants is finally back for another exciting botanical adventure! This week we explore another wonderful sand prairie in search of one of North America's most stunning terrestrial orchids - the orange fringed orchid (Platanthera ciliaris). Along the way, we meet a handful of great native plant species that are at home in these sandy soils.

Music by: 
Artist: Eyes Behind the Veil
Track: Folding Chair
Album: Besides
https://eyesbehindtheveil.bandcamp.com/

Wet Prairies and the White Lady's Slipper

This week we visit a wet prairie in search of the white lady's slipper orchid (Cypripedium candidum). This is a unique habitat type full of incredible plants and we meet many of them along the way. Special thanks to Paul Marcum (http://bit.ly/2r6SG8s) in making this episode possible! 

If you would like to support orchid conservation efforts here in North America, consider purchasing a stick over at http://www.indefenseofplants.com/shop/

Producer, Writer, Creator, Host:
Matt Candeias (http://www.indefenseofplants.com)

Producer, Editor, Camera:
Grant Czadzeck (http://www.grantczadzeck.com)

Twitter: @indfnsofplnts

Facebook: http://www.facebook.com/indefenseofpl...

Patreon: http://www.patreon.com/indefenseofplants

Tumblr: http://www.tumblr.com/indefenseofplants

_________________________________________________________________

Music by: 
Artist: Lazy Legs
Track: Chain of Pink
Album: Chain of Pink
http://lazylegs.bandcamp.com

Seed Anchor

[SOURCE]

Epiphytic plants live out their entire lives on the trunks or branches of trees. Using their roots, they attach themselves tightly to the bark. Spend any amount of time in the tropics and it will become quite clear that such a lifestyle has been very successful for a plethora of different plant families. Still, living on a tree isn't easy. Epiphytic plants must overcome harsh conditions among or near the canopy.

Photo by faatura licensed under CC BY-NC-ND 2.0

One of the biggest challenges these plants face starts before they even germinate. This is especially true for orchids. Orchid seeds are more like spores than they are seeds. They are so small that thousands could fit inside of a thimble. Upon ripening, the dust-like seeds waft away on the slightest breeze. In order for epiphytic species to germinate and grow, their seeds must somehow anchor themselves in place on a trunk or branch. Inevitably most seeds are doomed to fail. They simply will not land in a suitable location. It stands to reason then that any adaptation that increases their chances of finding the right kind of habitat will be favored. That's where the strange coils on the tip of Chiloschista seeds, a genus of leafless orchids native to southeast Asia, New Guinea, and Australia, come in. For these orchids, this process is aided by some truly unique seed morphology.

Unlike most orchid seeds that are nothing more than a thin sheath surrounding a tiny embryo, the seeds of Chiloschista have additional parts. These "appendages," which are specialized seed coat cells, are tightly wound into coils. Upon contact with water, these coils shoot out like tiny grappling hooks that grab on to moss and bark alike. In doing so, they anchor the seed in place. By securing their hold on the trunk or branch of a tree, the seeds are much more likely to germinate and grow. This is one of the most extreme examples of seed specialization in the orchid family.

Photo Credit: [1] [2]

Further Reading: [1]

Semi-Aquatic Orchids

By Jim Fowler. Copyright © 2017

Orchids have conquered nearly every continent on this planet except for Antarctica. In fact, there seems to be no end to the diversity in color, form, and habit of the world's largest family of flowering plants. Still, it might surprise many to learn that some orchids have even taken to water. Indeed, at least three species of orchid native to Latin and North America as well as a handful of islands have taken up a semi-aquatic lifestyle.

Most commonly encountered here in North America is the water spider orchid (Habenaria repens). It is a relatively robust species, however, considering that even its flowers are green, it is often hard to spot. Though it will root itself in saturated soils along the shore, it regularly occurs in standing water throughout the southeast. Often times, it can be found growing amidst other aquatic plants like pickerel weed (Pontederia cordata) and duck potato (Sagittaria latifolia). Because it can reproduce vegetatively, it isn't uncommon to find floating mats of comprised entirely of this orchid.  

By Jim Fowler. Copyright © 2017

Living in aquatic habitats comes with a whole new set of challenges. One of these is exposure to a new set of herbivores. Crayfish are particularly keen on nibbling plant material. In response to this, the water spider orchid has evolved a unique chemical defense. Coined "habenariol," this ester has shown to deter freshwater crayfish from munching on its leaves and roots. Another challenge is partnering with the right fungi. Little work has been done to investigate what kinds of fungi these aquatic orchids rely on for germination and survival. At least one experiment was able to demonstrate that the water spider orchid is able to partner with fungi isolated from terrestrial orchids, which might suggest that as far as symbionts are concerned, this orchid is a generalist.

The flowers of the water spider orchid are relatively small and green. What they lack in flashiness they make up for in structure and scent. The flowers are quite beautiful up close. The slender petals and long nectar spur give them a spider-like appearance. At night, they emit a vanilla-like scent that attracts their moth pollinators. 

Photo Credits: Jim Fowler. Copyright © 2017 www.jfowlerphotography.com

Further Reading: [1] [2] [3]

Orchid Dormancy Mediated by Fungi

Photo by NC Orchid licensed under CC BY-NC 2.0

North America's terrestrial orchids seem to have mastered the disappearing act. When stressed, these plants can enter into a vegetative dormancy, existing entirely underground for years until the right conditions return for them to grow and bloom. Cryptic dormancy periods like this can make assessing populations quite difficult. Orchids that were happy and flowering one year can be gone the next... and the next... and the next...

How and why this dormancy is triggered has confused ecologists and botanists alike. Certainly stress is a factor but what else triggers the plant into going dormant? According to a recent paper published in the American Journal of Botany, the answer is fungal.

Orchids are the poster children for mycorrhizal symbioses. Every aspect of an orchid's life is dependent on these fungal interactions. Despite our knowledge of the importance of mycorrhizal presence in orchid biology, no one had looked at how the abundance of mycorrhizal fungi influenced the life history of these charismatic plants until now.

By observing the presence and abundance of a family of orchid associated fungi known as Russulaceae, researchers found that the abundance of mycorrhizal fungi in the environment is directly related to whether or not an orchid will emerge. The team focused on a species of orchid known commonly as the small whorled pogonia (Isotria medeoloides). Populations of this federally threatened orchid are quite variable and assessing their numbers is difficult.

The team found that the abundance of mycorrhizal fungi is not only related to prior emergence of these plants but could also be used as a predictor of future emergence. This has major implications for orchid conservation overall. It's not enough to simply protect orchids, we must also protect the fungal communities they associate with.

Research like this highlights the need for a holistic habitat approach to conservation issues. So many species are partners in symbiotic relationships and we simply can't value one partner over the other. If conditions change to the point that they no longer favor the mycorrhizal partner, it stands to reason that it would only be a matter of years before the orchids disappeared for good.

Photo Credit: NC Orchid

Further Reading: [1]

A Peculiar Case of Bird Pollination

Via Johnson and Brown [SOURCE]

When we think of bird pollination, we often conjure images of a hummingbird sipping nectar from a long, tubular, red flower. Certainly the selection pressures brought about from entering into a pollination syndrome with birds has led to convergence in floral morphology across a wide array of different plant genera. Still, just when we think we have the natural world figured out, something new is discovered that adds more complexity into the mix. Nowhere is this more apparent than the peculiar relationship between an orchid and a bird native to South Africa.

The orchid in question is known scientifically as Disa chrysostachya. It is a bit of a black sheep of the genus. Whereas most Disa orchids produce a few large, showy flowers, this species produces a spike that is densely packed with minute flowers. They range from orange to red and, like most other bird pollinated flowers, produce no scent. 

Take the time to observe them in the field and you may notice that the malachite sunbird is a frequent visitor. The sunbirds perch themselves firmly on the spike and probe the shallow nectar spurs on each flower. At this point you may be thinking that the pollen sacs, or pollinia, of the orchid are affixed to the beak of the bird but, alas, you would be wrong. 

Closer inspection of the flowers reveal that the morphology and positioning of the pollinia are such that they simply cannot attach to the beak of the bird. The same goes for any potential insect visitors. The plant seems to have assured that only something quite specific can pick up the pollen. To see what is really going on, you would have to take a look at the sunbird's feet. 

That's right, feet. When a sunbird feeds at the flowers of D. chrysostachya, its feet position themselves onto the stiffened lower portion of the flower. This is the perfect spot to come into contact with the sticky pollinia. As the bird feeds, they pick up the pollinia on their claws! The next time the bird lands to feed, it will inevitably deposit that pollen. The orchids seemed to have benefited from the fact that once perched, sunbirds don't often reposition themselves on the flower spike. In this way, self pollination is minimized. A close relative, D. satyriopsis, has also appeared to enter into a pollination with sunbirds in a similar way. 

Though it may seem inefficient, research has shown that this pollination mechanism is quite successful for the orchid.The pollinia themselves stick quite strongly so that no amount of scuffing on branches or preening with beaks can dislodge them. Once pollination has been achieved, each flower is capable of producing thousands upon thousands of seeds.

Photo Credit: Johnson and Brown

Further Reading: [1]

The Lowly Lawn Orchid

A new year and a new orchid. It didn't take long for me to spot this little plant poking up between the succulent leaves of a potted aloe. My elation was short lived though. Alas, the sun was setting and I didn't have a flashlight or my camera. I was much luckier the next day. Actually, I shouldn't say lucky. This orchid isn't uncommon.

Meet the lawn orchid (Zeuxine strateumatica). Originally native to Asia, this species is expanding its range throughout many parts of the globe. Here in Florida, it was first discovered in 1936. There was a bit of confusion surrounding its origin on this continent, however, it is now believed that seeds arrived in a shipment of centipede-grass from China.

Since its premiere in Florida, the lawn orchid has since spread to Georgia, Alabama, and Texas. It seems to be quite tenacious, growing equally as well in lawns, floodplains, forests, meadows, and even sidewalk cracks! Despite this generalist habit, it does not seem to transplant well and is probably quite specific about its mycorrhizal partner. Much work needs to be done to sleuth out exactly why this little orchid has been able to spread so far outside of its native range.

Though small flies will visit the flowers, it is very likely that this orchid mostly self pollinates. It doesn't take long to flower and set seed. One plant can easily result in hundreds if not thousands of seedlings. After setting seed, the parent plant dies, however, it will often bud off new plantlets from its roots. Its ubiquitous nature can often stand in contrast to its ability to disappear for a series of time. Large stands that appear one year may not return for many years after. Still, in some areas this little orchid is abundant enough to be considered a nuisance.

Despite whatever feelings you may have towards this little plant, I nonetheless admire it. Its not often you find orchids so adaptable to a wide variety of conditions. At the very least it offers us insights into the success of plant invasions around the globe. And, in the end, its a nice looking little plant.

Further Reading: [1] [2]

Newly Discovered Orchid Doesn't Bother With Photosynthesis or Opening Its Flowers

Photo by Suetsugu Kenji [SOURCE]

A new species of orchid has been discovered on the small Japanese island of Kuroshima. Though not readily recognized as an orchid, it nonetheless resides in the tribe Epidendroideae. Although the flowers of its cousins are often quite showy, this orchid produces small brown blooms that never open. What's more, it has evolved a completely parasitic lifestyle. 

The discovery of this species is quite exciting. The flora of Japan has long thought to be well picked over by botanists and ecologists alike. Finding something new is a special event. The discovery was made by Suetsugu Kenji, associate professor at the Kobe University Graduate School of Science. This discovery was made about a year after a previous parasitic plant discovery made on another Japanese island a mere stones throw from Kuroshima.

Coined Gastrodia kuroshimensis, this interesting little parasite flies in the face of what we generally think of when we think of orchids. It is small, drab, and lives out its entire life on the shaded forest floor. Like the rest of its genus, G. kuroshimensis is mycoheterotrophic. It produces no leaves or chlorophyll, living its entire life as a parasite on mycorrhizal fungi underground. This is not necessarily bizarre behavior for orchids (and plants in general). Many different species have adopted this strategy. What was surprising about its discovery is the fact that its flowers never seem to open. 

In botany this is called "cleistogamy." It is largely believed that cleistogamy evolved as both an energy saving and survival strategy. Instead of dumping lots of energy into producing large, showy flowers to attract pollinators, that energy can instead be used for seed production and persistence. Additionally, since the flowers never open, cross pollination cannot occur. The resulting offspring share 100% of their genes with the parent plant. Although this can be seen as a disadvantage, it can also be an advantage when conditions are tough. If the parent plant is adapted to the specific conditions in which it grows, giving 100% of its genes to its offspring means that they too will be wonderfully adapted to the conditions they are born into. 

As you can probably imagine, pure cleistogamy can be quite risky if conditions rapidly change. In the face of continued human pressures and rapid climate change, cleistogamy as a strategy might not be so good. That is one reason why the discovery of this bizarre little orchid is so interesting. Whereas most species that produce cleistogamous flowers also produce "normal" flowesr that open, this species seems to have given up that ability. Thus, G. kuroshimensis offers researchers a window into how and why this reproductive strategy evolved. 

Photo Credit: Suetsugu Kenji

Further Reading: [1]

The Orchid Mantis Might Not be so Orchid After All

Here we see a juvenile orchid mantis perched atop a man-made orchid cultivar that would not be found in the wild. Photo by N. A. licensed under CC BY-NC-SA 2.0

The orchid mantis is a very popular critter these days, and rightly so. Native to southeast Asia, they are beautiful examples of how intricately the forces of natural selection can operate on a genome. The reasoning behind such mimicry is pretty apparent, right? The mantis mimics an orchid flower and thus, has easy access to unsuspecting prey.

Not so fast...

Despite its popularity as an orchid mimic, there is no evidence that this species is mimicking a specific flower. Most of the pictures you see on the internet are actually showing orchid mantids sitting atop cultivated Phalaenopsis or Dendrobium orchids that simply do not occur in the wild. Observations from the field have shown that the orchid mantis is frequently found on the flowers of Straits meadowbeauty (Melastoma polyanthum). A study done in 2013 looked at whether or not the mantids disguise offers an attractive stimulus to potential prey. Indeed, there is some evidence for UV absorption as well as convincing bilateral symmetry that is very flower-like. They also exhibit the ability to change their color to some degree depending on the background.

Orchid mantis nymphs are more brightly colored than adults. Photo by Frupus licensed under CC BY-NC 2.0

Despite our predilection for finding patterns (even when there are none) it is far more likely that this species has evolved to present a "generalized flower-like stimulus." In other words, they may simply succeed in tapping into pollinators' bias towards bright, colorful objects. We see similar strategies in non-rewarding flowering plants that simply offer a large enough stimulus that pollinators can't ignore them. The use of colored mantis models has provided some support for this idea. Manipulating the overall shape and color of these models had no effect on the number of pollinators attracted to them.

The most interesting aspect of all of this is that the most convincing (and most popular) mimicking the orchid mantis displays is during the juvenile phase. Indeed, most pictures circulating around the web of these insects are those of immature mantids. The adults tend to look rather drab, with long, brownish wing covers. However, they still maintain some aspects of the juvenile traits.

Adult orchid mantids take on a relatively drab appearance compared to their juvenile form. Photo by Philipp Psurek licensed under CC BY-SA 3.0 DE

The fact of the matter is, we still don't know very much about this species. It is speculated that the mimicry is both for protection and for hunting. As O'Hanlon (2016) put it, "The orchid mantis' predatory strategy can be interpreted as a form of 'generalized food deception' rather than 'floral mimicry'." It just goes to show you how easily popular misconceptions can spread. Until more studies are performed, the orchid mantis will continue to remain a beautiful mystery.

Photo Credit: [1] [2] [3]

Further Reading: [1] [2] [3] [4]