plant ecology

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Year of Pollination: More than Honey, etc.

When I decided to spend a year writing about pollinators and pollination, I specifically wanted to focus on pollinators besides the honey bee. Honey bees already get lots of attention, and there are loads of other pollinating organisms that are equally fascinating. But that’s just the thing, honey bees are incredibly fascinating. They have a strict and complex social structure, and they make honey – two things that have led humans to develop a strong relationship with them. We have been managing honey bees and exploiting their services for thousands of years, and we have spread them across the planet, bringing them with us wherever we go. In North America, honey bees are used to pollinate a significant portion of our pollinator-dependent crops, despite the fact that they are not native to this continent. In that sense, they are just another domesticated animal, artificially selected for our benefit.

It’s common knowledge that honey bees (and pollinators in general) have been having a rough time lately. Loss of habitat, urbanization, industrial farming practices, abundant pesticide use, and a variety of pests and diseases have been making life difficult for pollinators. Generally, when the plight of pollinators comes up in the news, reference is made to honey bees (or another charismatic pollinator, the monarch butterfly). News like this encourages people to take action. On the positive side, efforts made to protect honey bees can have the side benefit of protecting native pollinators since many of their needs are the same. On the negative side, evidence suggests that honey bees can compete with native pollinators for limited resources and can pass along pests and diseases. Swords are often double-edged, and there is no silver bullet.

In a recent conversation with a budding beekeeper, I was recommended the documentary, More than Honey. I decided to watch it, write a post about it, and call that the honey bee portion of the Year of Pollination. Part way through the movie, another documentary, Vanishing of the Bees, was recommended to me, and so I decided to watch both. Below are some thoughts about each film.

more than honey movie

More than Honey

Written and directed by Swiss documentary filmmaker, Markus Imhoof, this beautifully shot, excellently narrated, meandering documentary thrusts viewers into incredibly intimate encounters with honey bees. Cameras follow bees on their flights and into their hives and get up close and personal footage of their daily lives, including mating flights, waggle dances, pupating larvae, flower pollination, and emerging queens. In some scenes, the high definition shots make already disturbing events even more disturbing, like bees dying after being exposed to chemicals and tiny varroa mites crawling around on the bodies of bees infecting them with diseases – wings wither away and bees become too weak to walk. This movie is worth watching for the impressive cinematography alone.

But bees aren’t the only actors. The human characters are almost as fun to watch. A Swiss beekeeper looks out over stunning views of the Alps where he keeps his bees. He follows a long tradition of beekeeping in his family and is very particular about maintaining a pure breed in his hives, going so far as flicking away the “wrong” bees from flowers on his property and crushing the head off of an unfaithful queen. A commercial beekeeper in the United States trucks thousands of beehives around the country, providing pollination services to a diverse group of farms – one of them being a massive almond grove in California. He has been witness to the loss of  hundreds of honey bee colonies and has had to become “comfortable with death on an epic scale” – the grueling corporate world grinds along, and there is no time for mourning losses.

Further into the documentary, a woman in Austria demonstrates how she manipulates a colony into raising not just one queen, but dozens. She has spent years breeding bees, and her queens are prized throughout the world. A man in Arizona captures and raises killer bees – hybrid bees resulting from crosses between African and European honey bees (also known as Africanized honey bees). Despite their highly aggressive nature, he prefers them because they are prolific honey producers and they remain healthy without the use of synthetic pesticides.

Probably the darkest moment in the film is watching workers in China hand pollinate trees in an orchard. Excessive pesticide use has decimated pollinator populations in some regions, leaving humans to do the pollinating and prompting the narrator to reflect on the question, “Who’s better at pollinating, man or bees? Science answers with a definite, ‘not man.'”

Also included in the film is an intriguing discussion about bees as a super-organism with a German neuroscientist who is studying bee brains. The narrator sums it up like this: “Without its colony the individual bee cannot survive. It must subordinate its personal freedom for the good of the colony… Could it be that individual bees are like the organs or cells of a body? Is the super-organism as a whole the actual animal?”

Vanishing-of-the-bees

Vanishing of the Bees

Colony collapse disorder is a sometimes veiled yet important theme throughout More than Honey, and it was certainly something that drove the creation of the film. In the case of Vanishing of the Bees, colony collapse disorder is the reason for its existence. Narrated by actor, Ellen Page, and produced in part by a film production company called Hive Mentality Films, this movie came out on the heels of the news that bee colonies were disappearing in record numbers throughout the world. It tells the story of colony collapse disorder from the time that it first appeared in the news – one of the film’s main characters is the beekeeper that purportedly first brought attention to the phenomenon – and into the years that followed as scientists began exploring potential causes.

This film contains lots of important information and much of it seems credible, but it is also the type of documentary that in general makes me wary of documentaries. Its purpose goes beyond just trying to inform and entertain; it’s also trying to get you on board with its cause. I may agree with much of what is being said, but I don’t particularly like having my emotions targeted in an effort to manipulate me to believe a certain way. It’s a good idea not to let documentaries or any other type of media form your opinions for you. Consider the claims, do some of your own research and investigation, and then come to your own conclusion. That’s my advice anyway…even though you didn’t ask for it.

That being said, colony collapse disorder is a serious concern, and so I’ll end by going back to More than Honey and leave you with this quote by its narrator:

The massive death of honey bees is no mystery. What’s killing them is not pesticides, mites, antibiotics, incest, or stress, but a combination of all these factors. They are dying as a result of our civilization’s success, as a result of man, who has turned feral bees into docile, domestic animals – wolves into delicate poodles.

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A Rare Hawaiian Plant – Newly Discovered and Critically Endangered

Hawaii is home to scores of plant species that are found nowhere else in the world. But how did those plants get there? In geological time, Hawaii is a relatively young cluster of islands. Formed by volcanic activity occurring deep within the ocean, they only just began to emerge above water around 10 million years ago. At that point the islands would have been nearly devoid of life, and considering that they had never been connected to any other body of land and are about 2,500 miles away from the nearest continent, becoming populated with flora and fauna took patience and luck.

As far as plant life is concerned, seeds and spores had to either be brought in by the wind, carried across the ocean by its currents, or flown in attached to the feathers of birds. When humans colonized the islands, they brought seeds with them too; however, its estimated that humans didn’t begin arriving on the islands until about 1,700 years ago. The islands they encountered were no longer barren landscapes, but instead were filled with a great diversity of plant and animal life. A chance seed arriving on the islands once in a blue moon does not fully explain such diversity.

This is where an evolutionary process called adaptive radiation comes in. A single species has the potential to diverge rapidly into many new species. This typically happens in new habitats where little or no competition exists and there are few environmental stresses. Over time, as genetic diversity builds up in the population, individuals begin to adapt to specific physical factors in the environment, such as soil type, soil moisture, sun exposure, and climate. As individuals separate out into these ecological niches, they can become reproductively isolated from other individuals in their species and eventually become entirely new species.

This is the primary process that led to the great floral diversity we now see on the Hawaiian Islands. Adaptive radiations resulted in more than 1000 plant species diverging from around 300 seed introductions. Before western colonization, there were more than 1,700 documented native plant species. Much of this diversity is explained by the rich diversity of habitats present on the volcanic islands, which lead to many species becoming adapted to very specific sites and having very limited distributions.

A small population size and a narrow endemic range is precisely the reason why Cyanea konahuanuiensis escaped detection until recently. In September 2012, researchers on the island Oahu arrived at a drainage below the summit of Konahua-nui (the tallest of the Ko’olau Mountains). They were surveying for Cyanea humboldtiana, a federally listed endangered species that is endemic to the Ko’olau Mountains. In the drainage they encountered several plants with traits that differed from C. humboldtiana, including hairy leaves, smooth stems, and long, hairy calyx lobes. They took pictures and collected a fallen leaf  for further investigation.

Ko'olau Mountains of O'ahu (photo credit: wikimedia commons)

Ko’olau Mountains of O’ahu (photo credit: wikimedia commons)

Initial research suggested that this was a species unknown to science. More information was required, so additional trips were made, a few more individuals were found, and in June 2013, a game camera was installed in the area. The camera sent back three photos a day via cellular phone service and allowed the team of researchers to plan their next trip when they were sure that the flowers would be fully mature. Collections were kept to a minimum due to the small population size; however, using the material they could collect, further analyses and comparisons with other species in the Cyanea genus and related genera demonstrated that it was in fact a unique species, and so they gave it the specific epithet konahuanuiensis after the mountain on which it was found. It was also given a common Hawaiian name, Haha mili’ohu, which means “the Cyanea that is caressed by the mist.”

The hairy flowers and leaves of Cyanea konahuanuiensis. Purple flowers appear June-August. (photo credit: www.eol.org)

The hairy flowers and leaves of Cyanea konahuanuiensis. Purple flowers appear June-August. (photo credit: www.eol.org)

The total population of Cyanea konahuanuiensis consists of around 20 mature plants and a couple dozen younger plants. It is considered “critically imperiled” and must overcome some steep conservation challenges in order to persist. To start with, the native birds that pollinate its flowers and disperse its seeds may no longer be present. Also, it is likely being eaten by rats, slugs, and feral pigs. Add to that, several invasive plant species are found in the area and are becoming increasingly more common. While the researchers did find some seedlings in the area, all of the fruits that they observed aborted before they had reached maturity. Lastly, the population size is so small that the researchers say a landslide, hurricane, or flash flood “could obliterate the majority or all of the currently known plants with a single event.”

Seeds collected from immature fruits from two plants were sown on an agar medium at the University of Hawaii Harold L. Lyon Arboretum. The seeds germinated, and so the researchers plan to continue to collect seeds “in order to secure genetic representations from all reproductively mature individuals in ex situ collections.”

Single stem of Cyanea konahuanuiensis (photo credit: www.eol.org)

Single stem of Cyanea konahuanuiensis (photo credit: www.eol.org)

C. konahuanuiensis is not only part of the largest botanical radiation event in Hawaii, but also the largest on any group of islands. At some point in the distant past, a single plant species arrived on a Hawaiian island and has since diverged into at least 128 taxa represented in six genera, Brighamia, Clermontia, Cyanea, Delissea, Lobelia, and Trematolobelia, all of which are in the family Campanulaceae – the bellflower family. Collectively these plants are referred to as the Hawaiian Lobelioids. Cyanea is by far the most abundant genus in this group consisting of at least 79 species. Many of the lobelioids have narrow distributions and most are restricted to a single island.

Sources

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Poisonous Plants: Baneberry

For all the benefits that plants offer humanity – the distillation being that Earth would be uninhabitable without them – there is still reason to be wary of them. In a world lousy with herbivores, plant species that are unpalatable have a greater chance of survival. Inflicting serious injury or death upon being ingested – or even by coming in contact with an unsuspecting visitor – offers even greater assurance that a plant will survive long enough to reproduce, passing along to its progeny any traits that led to its superior fitness. The traits in this case are chemical compounds that can be toxic when delivered at the right dose to the right organism. This is the nature of poisonous plants, and the reason why from a young age we were all likely warned not to eat every tasty looking berry we come across and not to go tromping carelessly through an area where certain plants might be present. Plants aren’t out to get us per se, but some do have the potential to cause us great harm. Informing ourselves and taking precautions is advised.

This is the first in a series of posts about poisonous plants. The list of poisonous plants is long, so it’s going to take a while to get through them all. There are some plants that are not generally considered poisonous but can cause illness or death to those who are allergic to them – like peanuts. I don’t plan to include such plants, but there may be some exceptions along the way. The popular author Amy Stewart wrote a book about poisonous and other nefarious plants entitled, Wicked Plants: The Weed that Killed Lincoln’s Mother and other Botanical Atrocities. Below is an excerpt from her introduction to that book that I thought would be worth including here:

Do not experiment with unfamiliar plants or take a plant’s power lightly. Wear gloves in the garden; think twice before swallowing a berry on the trail or throwing a root into a stew pot. If you have small children, teach them not to put plants in their mouths. If you have pets, remove the temptation of poisonous plants from their environment. The nursery industry is woefully lax about identifying poisonous plants; let your garden center know that you’d like to see sensible, accurate labeling of plants that could harm you. Use reliable sources to identify poisonous, medicinal, and edible plants. (A great deal of misinformation circulates on the Internet, with tragic consequences.)

Baneberry (Actaea spp.)

“Bane” is defined as deadly poison or a person or thing that causes death, destruction, misery, distress, or ruin. The word seems fitting as a common name to describe a plant with a berry that when ingested is said to have an almost immediate sedative effect on the heart and can ultimately lead to cardiac arrest. Baneberry is a name given to several plants in the genus Actaea, two of which are the main focus of this post – red baneberry (Actaea rubra) and white baneberry (Actaea pachypoda).

Actaea is in the family Ranunculaceae – the buttercup family – a family that consists of several common ornamental plants including those in the genera Ranunculus, Delphinium, and Clematis. A. rubra and A. pachypoda are commonly found in the understory of wooded areas in North America – A. rubra is the most widespread of the two species, occurring throughout North America except Mexico and the southeastern U.S. states; A. pachypoda occurs in eastern Canada and most eastern and Midwestern U.S. states.

The flowers of red baneberry, Actaea rubra (photo credit: wikimedia commons)

The flowers of red baneberry, Actaea rubra (photo credit: wikimedia commons)

Red baneberry is an herbaceous perennial that emerges in the spring from a basal stem structure called a caudex or from a rhizome, dying back to the ground again in the fall. One or several branching stems reach from 1 to 3 feet high, each with compound leaves consisting of 2-3 leaflets. The leaflets are deeply lobed and coarsely toothed. Several small, white flowers appear in spring to early summer clustered together in an inflorescence called a raceme. The petals are inconspicuous, but the stamens are large and showy. The flowers are said to have a rose-like scent. A variety of insects pollinate the flowers, after which green berries form, turning red or occasionally white by mid to late summer.

The berries of red baneberry, Actaea rubra (photo credit: www.eol.org)

The berries of red baneberry, Actaea rubra (photo credit: www.eol.org)

Red baneberry occurs on diverse soil types and in diverse ecosystems across its expansive native range. It seems to prefer, moist, shady, nutrient rich, acidic sites, and is considered an indicator of such places. It can be found in deciduous, coniferous, and mixed forested areas. Its preference for moist sites means that it can also be found in swamps, along stream banks, and in other riparian areas.

White baneberry has a relatively smaller native range and is found in very similar environments. It also has many of the same features and habits as red baneberry, with the main distinction being its striking white berries formed on prominent, stout, bright red axes and peduncles (the “stems” and “branches” of the racemes). The stigmas are persistent on the berries, forming large black dots on each berry and giving it another common name, doll’s eyes. This is a feature of red baneberry as well, but is much more striking on the white berries.

Baneberry is occasionally browsed by livestock and wildlife including deer, elk, and small mammals. However, it has a low degree of palatability and isn’t very nutritious. Birds, unaffected by their poisonous qualities, eat the berries and are the main seed dispersers of baneberry.

The berries of white baneberry or doll's eyes Actaea pachypoda (photo credit: www.eol.org)

The berries of white baneberry or doll’s eyes, Actaea pachypoda (photo credit: www.eol.org)

The roots and berries are the most poisonous parts of baneberry, however all parts are toxic. The berries are quite bitter, so it is not likely that one would eat enough of them to receive a severe reaction. If ingested, symptoms include stomach cramps, dizziness, vomiting, diarrhea, delirium, and circulatory failure. Eating six or more berries can result in respiratory distress and cardiac arrest. The toxin in the plant has yet to be clearly identified. Protoanemonin is present, as it is in all plants in the buttercup family, but the real toxicity of the plant is probably due to an essential oil or a poisonous glycoside. There have been no reported deaths due to the consumption of red or white baneberry, but a European species of baneberry (A. spicata) has been linked to the death of several children.

Native Americans were aware of baneberry’s toxicity, so rather than use it as a food source, they used it medicinally. Among other things, the root was used as a treatment for menstrual cramps, postpartum pain, and issues related to menopause, and the berry was used to induce vomiting and diarrhea and as a treatment for snakebites. Leaves were chewed and applied to boils and wounds. Two websites I visited claimed that arrowheads were dipped in the juice of the berries to make poison arrows. Neither cited a reference, and in the section on arrow poisons in Wicked Plants, Stewart doesn’t mention baneberry. However, that doesn’t mean it didn’t happen.

What do you fear the most? Batman villian, Bane, or baneberry? (photo credit: Comic Vine)

What do you fear the most? Batman villian, Bane, or baneberry? (photo credit: Comic Vine)

References

 

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Year of Pollination: Pollination Syndromes and Beyond

A discussion of pollination syndromes should begin with the caveat that they are a largely outdated way to categorize plant-pollinator interactions. Still, they are important to be aware of because they have informed so much of our understanding about pollination biology, and they continue to be an impetus for ongoing research. The concept of pollination syndromes exists in part because we are a pattern seeking species, endeavoring to place things in neat little boxes in order to make sense of them. This is relatively easy to do in a hypothetical or controlled environment where the parameters are selected and closely monitored and efforts are made to eliminate noise. However, the real world is considerably more dynamic than a controlled experiment and does not conform to black and white ways of thinking. Patterns are harder to unveil, and it takes great effort to ensure that observed patterns are genuine and not simply imposed by our pattern seeking brains.

That being said, what are pollination syndromes?  Pollination syndromes are sets of floral traits that are thought to attract specific types of pollinators. The floral traits are considered to have evolved in order to appeal to a particular group of pollinators – or in other words, selective pressures led to adaptations resulting in mutualistic relationships between plants and pollinators. Pollination syndromes are examples of convergent evolution because distantly related plant species have developed similar floral traits, presumably due to similar selection pressures. Pollination syndromes were first described by Italian botanist, Federico Delpino, in the last half of the 19th century. Over several decades his rudimentary ideas were fleshed out by other botanists, resulting in the method of categorization described (albeit briefly) below.

Honey bee on bee's friend (Phacelia tanacetifolia)

A honey bee getting friendly with bee’s friend (Phacelia tanacetifolia)

Pollination by bees (melittophily) – Flowers are blue, purple, yellow, or white and usually have nectar guides. Flowers are open and shallow with a landing platform. Some are non-symmetrical and tubular like pea flowers. Nectar is present, and flowers give off a mild (sometimes strong) sweet scent.

Pollination by butterflies (psychophily) – Flowers are pink, purple, red, blue, yellow, or white and often have nectar guides. They are typically large with a wide landing pad. Nectar is inside a long, narrow tube (or spur), and flowers have a sweet scent.

Pollination by hawkmoths and moths (sphingophily and phalaenophily) – Moth pollinated flowers open at night, have no nectar guides, and emit a strong, sweet scent. Flowers pollinated by hawkmoths are often white, cream, or dull violet and are large and tubular with lots of nectar. Those pollinated by other moths are smaller, not as nectar rich, and are white or pale shades of green, yellow, red, purple, or pink.

Pollination by flies (myophily or sapromyophily) – Flowers are shaped like a basin, saucer, or kettle and are brown, brown-red, purple, green, yellow, white, or blue.  Some have patterns of dots and stripes. If nectar is available, it is easily accessible. Their scent is usually putrid. A sapromyophile is an organism that is attracted to carcasses and dung. Flies that fall into this category visit flowers that are very foul smelling, offer no nectar reward, and essentially trick the fly into performing a pollination service.

Pollination by birds (ornithophily) –  Flowers are usually large, tubular, and red, orange, white, blue, or yellow. They are typically without nectar guides and are odorless since birds don’t respond to scent. Nectar is abundant and found at various depths within the flower.

Pollination by bats (chiropterophily) – Flowers are large, tubular or bell shaped, and white or cream colored with no nectar guides. They open at night, have abundant nectar and pollen, and have scents that vary from musty to fruity to foul.

Pollination by beetles (cantharophily) – Flowers are large and bowl shaped and green or white. There are no nectar guides and usually no nectar. The scent is strong and can be fruity, spicy, or putrid. Like flies, some beetles are sapromyophiles.

Locust borer meets rubber rabbitbrush (Ericameria nauseosa)

A locust borer meets rubber rabbitbrush (Ericameria nauseosa)

In addition to biotic pollination syndromes, there are two abiotic pollination syndromes:

Pollination by wind (anemophily) – Flowers are miniscule and brown or green. They produce abundant pollen but no nectar or odor. The pollen grains are very small, and the stigmas protrude from the flower in order to capture the windborne pollen.

Pollination by water (hydrophily) –  Most aquatic plants are insect-pollinated, but some have tiny flowers that release their pollen into the water, which is picked up by the stigmas of flowers in a similar manner to plants with windborne pollen.

This is, of course, a quick look at the major pollination syndromes. More complete descriptions can be found elsewhere, and they will differ slightly depending on the source. It’s probably obvious just by reading a brief overview that there is some overlap in the floral traits and that, for example, a flower being visited by a bee could also be visited by a butterfly or a bird. Such an observation explains, in part, why this method of categorizing plant-pollinator interactions has fallen out of favor. Studies have been demonstrating that this is not a reliable method of predicting which species of pollinators will pollinate certain flowers. A close observation of floral visitors also reveals insects that visit flowers to obtain nectar, pollen, and other items, but do not assist in pollination. These are called robbers. On the other hand, a plant species may receive some floral visitors that are considerably more effective and reliable pollinators than others. What is a plant to do?

Pollination syndromes imply specialization, however field observations reveal that specialization is quite rare, and that most flowering plants are generalists, employing all available pollinators in assisting them in their reproduction efforts. This is smart, considering that populations of pollinators fluctuate from year to year, so if a plant species is relying on a particular pollinator (or taxonomic group of pollinators) to aid in its reproduction, it may find itself out of luck. Considering that a flower may receive many types of visitors on even a semi-regular basis suggests that the selective pressures on floral traits may not solely include the most efficient pollinators, but could also include all other pollinating visitors and, yes, even robbers. This is an area where much more research is needed, and questions like this are a reason why pollination biology is a vibrant and robust field of research.

A bumble bee hugs Mojave sage (Salvia pachyphylla)

A bumble bee hugs the flower of a blue sage (Salvia pachyphylla)

Interactions between plants and pollinators is something that interests me greatly. Questions regarding specialization and generalization are an important part of these interactions. To help satiate my curiosity, I will be reading through a book put out a few years ago by the University of Chicago Press entitled, Plant-Pollinator Interactions: From Specialization to Generalization, edited by Nickolas M. Waser and Jeff Ollerton. You can expect future posts on this subject as I read through the book. To pique your interest, here is a short excerpt from Waser’s introductory chapter:

Much of pollination biology over the past few centuries logically focused on a single plant or pollinator species and its mutualistic partners, whereas a focus at the level of entire communities was uncommon. Recently we see a revival of community studies, encouraged largely by new tools borrowed from the theory of food webs that allow us to characterize and analyze the resulting patterns. For example, pollination networks show asymmetry – most specialist insects visit generalist plants, and most specialist plants are visited by generalist insects. This is a striking departure from the traditional implication of coevolved specialists!

References:

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How Pitcher Plants Eat Bugs (Frog Optional)

SAMSUNG

A few months ago at work I captured this photo of a frog inside of a pitcher plant. Do you see it? It is pretty well camouflaged and poking its head out just enough to intercept curious insects lured in by the promise of nectar, eating them before they can make their way into the tube. Either way, approaching insects are about to meet their fate. Whether by plant or by frog, they are destined to be consumed lest they turn away in time.

This frog was hiding inside the modified leaf of a species of Sarracenia, a carnivorous plant commonly known as a North American pitcher plant. There are at least eight species of Sarracenia, all of which naturally occur in the southeastern region of the United States. One species, Sarracenia purpurea, also occurs in the northeast, the upper Midwest, and throughout much of Canada. Sarracenia is in the family Sarraceniaceae along with two other genera of pitcher plants, Darlingtonia (the cobra plant, native to northern California and southern Oregon) and Heliamphora (the sun pitchers, native to South America). Plants in this family are not to be confused with the distantly related tropical pitcher plants which are in the genus Nepenthes (family Nepentheaceae).

The natural habitats of Sarracenia are sunny, open areas that remain permanently wet, including meadows, savannahs, fens, and swamps. The soils are acidic, nutrient poor, and typically composed of sandy peat commonly derived from sphagnum moss. In the southeast, less than 5% of the original (pre-European settlement) Sarracenia habitat remains, threatening its survival in the wild. Sarracenia oreophila (green pitcher plant) is currently listed as critically endangered on the IUCN Red List.

Flowering occurs in the spring, usually before pitchers form. Individual flowers are formed on tall stalks that rise straight up and then bend at the very top, hanging the flower upside down. Early flowering and tall flower stalks help prevent pollinating insects from being consumed by the plant. In his book The Savage Garden, Peter D’Amato describes the flowers as “showy, brilliant, and very unusual – a wonderful bonus to an already handsome class of foliage plants.” The flowers are either yellow or a shade of red and last about two weeks, after which the petals drop and a seed pod forms. Seeds are released from the fruits in the fall.

Flower of Sarracenia rubra (sweet pitcherplant) - photo credit: www.eol.org

Flower of Sarracenia rubra (sweet pitcher plant) – photo credit: www.eol.org

D’Amato writes that Sarracenia are among the “most ravenous” plants, with each leaf having the potential of trapping “thousands of nasty insects.” In some cases pitchers even flop over, heavy with the weight of bugs inside them. The specifics of capturing and killing insects varies between species of Sarracenia, but in general prey is lured to the opening of the pitcher with a combination of nectar, scent, and color. Upon entering the tube, gravity, waxy surfaces, drugs, and hairs force the captives downward where they are eventually consumed by enzymes and microbes. Digested insects provide the plant with nutrients necessary for growth – nutrients that otherwise are taken up by the roots of plants that occur in more nutrient rich soils.

Sarracenia purpurea (purple pitcher plant) is unique in that its pitchers lack a “hood” or “lid” – a standard feature of other species of Sarracenia that helps keep rain from entering the pitchers. Instead, the pitchers fill with water and insects are killed by drowning. The most brutal killer is probably Sarracenia psittacina (parrot pitcher plant) which has an additional opening inside of its pitcher. The opening is small and difficult to find again once an insect is on the wrong side of it. The inside walls of the pitcher are covered in long, sharp, downward pointing hairs, and the struggling insect is pierced repeatedly by the hairs as it makes its way to the bottom of the tube to be digested.

Hoodless pitchers of Sarracenia purpurea (photo credit: www.eol.org)

Hoodless pitchers of Sarracenia purpurea (photo credit: www.eol.org)

Hooded pitchers of Sarracenia leucophylla (photo credit: www.eol.org)

Hooded pitchers of Sarracenia leucophylla (photo credit: www.eol.org)

According to D’Amato, “the Sarracenia are one of the simplest carnivorous plants to grow, and certainly among the most fun and rewarding.” Learn more about growing North American pitcher plants by consulting D’Amato’s book and/or by visiting the website of the International Carnivorous Plant Society.

Want to learn more about Sarracenia? The Plants are Cool, Too! web series has a great video about them:

Other carnivorous plant posts:

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Year of Pollination: The Anatomy of a Bee

A greater appreciation for pollinators can be had by learning to identify them – being able to tell one from another and calling them by name. Anyone can tell a butterfly from a bee, but how about telling a sweat bee from a leafcutter bee? Or one species of sweat bee from another species of sweat bee? That takes more training. This is where knowing the parts of a bee becomes important.

I am new to learning the names of pollinators. I’ve been learning the names of plants for many years now (and I still have a long way to go), but my knowledge of insect identification is largely limited to one entomology course I took in college and the occasional reading about insects in books and magazines. So, this post is just as much for me as it is for anybody else. It also explains why it is brief and basic. It’s for beginners.

This first illustration is found in the book Pollinators of Native Plants by Heather Holm. The book starts with brief overviews of pollination, pollinators, and pollinator conservation, but then spends nearly 200 pages profiling specific plants and describing the particular species of pollinating insects that visit them. The photos of the insects are great and should be very useful in helping to identify pollinators.

bee anatomy_pollinators of native plants book

This next illustration is from the book California Bees and Blooms by Gordon W. Frankie, et al. The title is a bit deceptive because much of what is found in this book is just as applicable to people outside of California as it is to people within. There is some discussion about plants and pollinators specific to California and the western states, but there is also a lot of great information about bees, flowers, and pollination in general, including some great advice on learning to identify bees. The book includes this basic diagram, but it also provides several other more detailed illustrations that help further describe things like mouth parts, wings, and legs.

bee anatomy_california bees and blooms book

As part of their discussion on identifying bees, the authors of California Bees and Blooms offer these encouraging and helpful words to beginners like me: “Even trained taxonomists must examine most bees under a microscope to identify them to species level, but knowing the characteristics to look for can give you a pretty good idea of the major groups and families of bees that are visiting your garden. These include size, color, and features of the head, thorax, wings, and abdomen.”

If you would like to know more about the pollinators found in your region, including their names, life history, and the plants they visit, books like the aforementioned are a good start. Also, find yourself a copy of a field guide for the insects in your area and a good hand lens. Then spend some time outside closely and quietly observing the busy lives of the tiny things around you. I plan to do more of this sort of thing, and I am excited see what I might find. Let me know what you find.

Here are a few online resources for learning more about bee anatomy and bee identification:

Other “Year of Pollination” Posts:

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Using Plant Root and Mycorrhizal Fungal Traits to Predict Soil Structure

The March 2015 issue of New Phytologist is a Special Issue exploring the “ecology and evolution of mycorrhizas.” A mycorrhiza is a symbiotic association between a fungus and the roots of a plant. The introductory editorial of this special issue asserts that “almost all land plant species form a symbiosis with mycorrhizal fungi.” Generally, the association benefits both plant and fungus. The plant gains greater access to water and mineral nutrients by the way of fungal hyphae, and the fungus recieves carbohydrates (glucose and sucrose) that have been synthesized in the leaves of the plant and transported down into its roots. We have been aware of this relationship since at least the middle of the 19th century, but recent advances in technology have given us new insight into just how extensive and important it is . “Plants cannot be considered as isolated individuals anymore, but as metaorganisms or holobionts encompassing an active microbial community re-programming host physiology.”

However, there are still “critical gaps” in our understanding of mycorrhizas, hence the special issue of New Phytologist. In this issue they endeavor to address the following questions: “How is the balance of mutualism maintained between plants and fungi? What is the role of mycorrhizal fungi in the soil ecosystem? What controls fungal community composition, and how is diversity maintained?” There is so much more to learn, but the research presented in this issue has us moving in the right direction. If you are interested in this sort of thing, I encourage you to check out the entire issue. I have picked out just 2 of the 32 articles to present here – one this week and the other next week.

photo credit: wikimedia commons

photo credit: wikimedia commons

Plant root and mycorrhizal fungal traits for understanding soil aggregation by Matthias C. Rillig, Carlos A. Aguilar-Trigueros, Joana Bergmann, Erik Verbruggen, Stavros D. Veresoglou, and Anika Lehmann

Soil structure is determined by the size, shape, and extent of soil aggregates and the resulting pore spaces found between them. The arrangement of soil aggregates and pore spaces helps determine the availability and movement of water and air and also has an influence on the growth and movement of micro- and macroorganisims, including fungi, plant roots, bacteria, and arthropods. The authors state that “soil aggregation is important for root growth and for a wide range of soil features and ecosystem process rates, such as carbon storage and resistance to erosion.”

Soil aggregates are composed mainly of clay particles, organic matter (including plant roots), organic compounds (produced by bacteria and fungi), and fungal hyphae. There has been plenty of research on soil aggregation, but much of it is focused on management practices and physical chemical factors. Less is known about the contribution of plant roots and mycorrhizal fungi to the formation and stabilization of soil aggregates. We know they play a role, but we lack understanding about the extent to which soil aggregation can be predicted not just by abiotic factors but also by the presence of plants and mycorrhizal fungi. The authors of this paper propose a widespread, trait-based approach to researching this topic, recognizing that “summarizing ecological characteristics of species by means of traits has become an essential tool in plant ecology.”

Possible traits to be considered were grouped into two categories: formation-related traits and stabilization-related traits. Formation refers to “the initial binding together of particles” to form an aggregate. Stabilization is a process in which aggregates are “increasingly resistant to the application of disintegrating forces, such as water penetrating into pores.” These two processes (along with disintegration) are occurring simultaneously in virtually all soils, but they “may be executed by different organisms expressing different traits.” Some of the formation traits include length, extension ability, and relative growth of roots and hyphae; root and hyphae exudate quality and quantity; and the “ability of roots or hyphae to bring soil particles together by moving them, leading to potential aggregation.” Stabilization traits include tensile strength, density, and “entangling ability” of roots and hyphae; water repellency of the aggregates and cementation capability of the exudates; and the life span, palatability, and repair capacity of roots and hyphae.

photo credit: wikimedia commons

photo credit: wikimedia commons

The amount of time and effort it will take to measure the traits of each and every plant and mycorrhizal fungi species and to determine the extent to which those traits contribute to soil aggregation will be considerable. The authors acknowledge that “some of these traits will be relatively easy to measure,” while “others will be quite challenging.” However, as technologies advance, the mysterious world under our feet should become easier to explore. As the traits of each species of plant and fungi are measured, a database can be constructed and eventually used to determine the plant/fungi combinations that are the best fits for restoring and conserving the soils of specific regions.

Ultimately, this research may help us answer various questions, including whether or not we can use a survey of plant and mycorrhizal fungi (along with soil type, climate, and management) to predict soil aggregation. Ecosytem restoration efforts may also benefit if we are able to produce “tailor-made mycorrhizal fungi inocula and seed mixes” in order to “enhance soil aggregation.” Better understanding of these traits could also be applied to sustainable agriculture in areas such as crop breeding and cover crop selection. This research is in the hypothesis phase right now, and “only controlled experiments employing a range of plant and fungal species” can reveal the role that certain plant root and mycorrhizal fungal traits play in soil aggregation as well as the full range of applications that this information might have.

Speaking of soil, did you know that the 68th United Nations General Assembly declared 2015 the International Year of Soils? The purpose of this declaration is to “increase awareness and understanding of the importance of soil for food security and essential ecosystem functions.” You can read a list of “specific objectives” on their About page.

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Year of Pollination: Dung Moss

Last year I wrote about two groups of plants that emit foul odors when they bloom: corpse flowers and carrion flowers. Their scent is akin to the smell of rotting flesh, hence their common names. The purpose of this repugnant act is to attract a specific group of pollinators: flies, carrion beetles, and other insects that are attracted to gross things. Though this particular strategy is rare, these aren’t the only plants that have evolved to produce stinky smells in order to recruit such insects to aid in their reproductive processes. For one, there is a very unique group of mosses that do this, commonly known as dung mosses. Judging from the name, you can probably imagine what their smell must be like. However, their common name doesn’t just describe their scent, but also where they live.

At least three genera (Splachnum, Tetraplodon, and Tayloria) in the family Splachnaceae include species that go by the common name, dung moss. All Splachnum and Tetraplodon species and many species in the genus Tayloria are entomophilous. Entomophily is a “pollination syndrome”, a subject we will explore more thoroughly in future posts, in which pollen or spores are distributed by insects. Compare this to anemophily, or wind pollination, which is the more common way that moss spores are distributed. In fact, dung mosses are the only mosses known to exhibit entomophily.

Dung Moss (photo credit: wikimedia commons)

Dung Moss (photo credit: wikimedia commons)

Before we go too much further, it’s probably important to have a basic understanding of how mosses differ from other plants. Mosses are in a group of non-vascular and non-flowering plants called bryophytes. Vascular tissues are the means by which water and nutrients are transported to and from different plant parts. Lacking vascular tissues, water and nutrients are simply absorbed by the leaves of bryophytes (although some species have structures akin to vascular tissue), which is why they typically grow low to the ground and in moist environments. Bryophytes also lack true roots and instead have rhizoids, threadlike structures that anchor the plants to the ground or to some other substrate (such as dung).

Another major distinction between bryophytes and other plants is that bryophytes spend most of their life cycle as a haploid gametophyte rather than a diploid sporophyte (haploid meaning that it only has one set of chromosomes; diploid meaning that there are two sets of chromosomes, one from the father and one from the mother). In most plants, the haploid gametophyte is a sperm (pollen) or an egg. In bryophytes, the familiar green, leafy structure is actually the gametophyte. The gametophyte houses sperm and egg cells, and when the egg is fertilized by sperm it forms a zygote that develops into the sporophyte structure which extends above the leafy gametophyte. A capsule at the top of the sporophyte contains spores which are eventually released and, upon finding themselves on a suitable substrate in a hospitable environment, germinate to produce new plants. The spore then is comparable to a seed in vascular, seed-bearing plants.

photo credit: wikimedia commons

photo credit: wikimedia commons

As stated earlier, the spores of most mosses are distributed by wind. Dung mosses, on the other hand, employ flies in the distribution of their spores. They attract the flies by emitting scents that only flies can love from an area on the capsule of the sporophyte called the apophysis. This area is often enlarged and brightly colored in yellow, magenta, or red, giving it a flower-like appearance which acts as a visual attractant. The smells emitted vary depending on the type of substrate a particular species of dung moss has become adapted to living on. Some dung mosses grow on the dung of herbivores and others on the dung of carnivores. Some even prefer the dung of a particular group of animals; for example, a population of Tetraplodon fuegiensis was found to be restricted to the feces and remains of foxes. However, dung is not the only material that dung mosses call home.  Certain species grow on carrion, skeletal remains, or antlers. The smells these species produce attract flies that prefer dead flesh and bone in various states of decay.

Yellow Moosedung Moss (Splachnum luteum) has one of the largest and showiest sporophytes. (photo credit: www.eol.org)

Yellow Moosedung Moss (Splachnum luteum) has one of the largest and showiest sporophytes. (photo credit: www.eol.org)

The spores of dung mosses are small and sticky. When a fly visits these plants, the spores adhere to its body in clumps. The fly then moves on to its substrate of choice to lay its eggs, and the spores are deposited where they will then germinate and grow into new moss plants. Flies that visit dung mosses receive nothing in return for doing so, but instead are simply “tricked” into disseminating the propagules. The story is similar with corpse flowers and carrion flowers; flies are drawn in by the smells and recruited to transmit pollen but receive no nectar reward for their work.

There are 73 species in the Splachnaceae family, and nearly half of these species are dung mosses. These mosses are mostly found in temperate habitats in both the northern and southern hemispheres, with a few species occurring in the mountains of subtropical regions. They can be found in both wet and relatively dry habitats. Dung mosses are generally fast growing but short lived, with some lasting only about 2 years. It isn’t entirely clear how and why mosses in this family evolved to become entomophilous, but one major benefit of being this way is that their spores are reliably deposited on suitable habitat. Because of this directed dispersal, they can produce fewer and smaller spores, which is an economical use of resources.

Sporophytes of Splachnum vasculosum (photo credit: www.eol.org)

Sporophytes of Splachnum vasculosum (photo credit: www.eol.org)

References

Koponen, A. 2009. Entomophily in the Splachnaceae. Botanical Journal of the Linnean Society 104: 115-127.

Marino, P., R. Raguso, and B. Goffinet. 2009. The ecology and evolution of fly dispersed dung mosses (Family Splachnaceae): Manipulating insect behavior through odour and visual cues. Symbiosis 47: 61-76.

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Palm Oil Production and Its Threat to Biodiversity

Improvements in cultivated varieties of oil palms could have devastating ecological effects. This is according to an article published in a recent issue of Science. Doom doesn’t have to be the story though, if – as the authors suggest – governments and conservation organizations take proper action to safeguard vulnerable land.

Palm oil is a versatile vegetable oil derived from the fruits of oil palms. It has myriad culinary uses and is also used in the manufacturing of cosmetics and the production of biofuel. Oil palms have high yields, easily outyielding other major oil crops like soybean, rapeseed, and sunflower. Oil palms are grown in the tropics in developing countries where land and labor are inexpensive. As human population grows, demand for palm oil increases. To meet the demand, tropical forests are converted into agricultural land. The majority of palm oil production occurs in Southeast Asian countries like Indonesia and Malaysia. However, palm oil production is expected to increase in African and Latin American countries as new varieties better suited for these particular environments become available.

oil world graph

Genome sequencing of oil palm may allow plant breeders to develop varieties that are disease resistant, drought tolerant, and able to grow in salinized soils. Already making its debut, though, is a new variety of oil palm that is boasting yields from 4 tons to as much as 10 tons per hectare. Higher yielding varieties could be the solution to preventing more tropical forests from being converted into oil palm plantations. Or could they lead to more growth? Intrigued by the development of improved varieties of oil palms and other tropical crops, the authors of this study developed computer models in order to determine what this might mean for the future.

African Oil Palm (Elaeis guineensis) is the species of oil palm most commonly grown for palm oil production.

African Oil Palm (Elaeis guineensis) is the species of oil palm most commonly grown in palm oil production (photo credit: www.eol.org)

The results of simulations suggested two possible outcomes: one potentially positive and the other largely negative. On the positive side, “an assumed 56% increase in oil palm yield per tree in Malaysia and Indonesia” could result in ” around 400,000 hectares of agricultural land…taken out of production in Brazil, India, and Canada.” This is because less land will be needed to meet the demand, and the increased availability and resulting lower price of palm oil will outcompete other oil crops (like rapeseed, which is one of Canada’s main agricultural crops). However, the author’s seem to assume that agricultural land taken out of production will be restored back into natural lands. I find this argument hard to accept. Anecdotal evidence suggests that if farmers are no longer making a profit from a particular crop, they will choose to either grow something more profitable or sell their land to developers. A concerted effort would have to be made to capture this land and ensure that it remain uncultivated and undeveloped. Also, as the author’s point out, restoring land in Canada is very different from restoring or protecting tropical land. Loss of biodiversity is a much greater risk in areas where the level of biodiversity per hectare is high.

On the negative side, higher yields can encourage increased production. Tropical forest conversion may accelerate if farmers see an opportunity for growth. Additionally, improved varieties may increase palm oil production in African and Latin American countries, resulting again in more land conversion and deforestation. This effect may also become the story, not just for oil palms, but for cacao, eucalyptus, coffee, and other tropical crops as varietal improvements are achieved.

Oil Palm Friuits (photo credit: www.eol.org)

Oil Palm Friuits (photo credit: www.eol.org)

In light of this predicted consequence, the authors of this study recommend that governments, working together with conservation organizations and industry associations, regulate the conversion of agricultural lands and ensure that certain areas are specifically set aside for conservation. This means that “models of the drivers of environmental change” must be developed that “incorporate feedbacks at a range of scales” so that measures can be put into place to address “the unintended negative consequences of technical advances.”

More information on sustainable palm oil production can be found here.

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Article: The Wildest Idea on Earth

Imagine living in close proximity to numerous national parks and being “enveloped by connected [wildlife] corridors” that lead to these national parks – or as Edward O. Wilson envisions them, “national biodiversity parks, a new kind of park that won’t let species vanish.” Wilson – a renowned biologist, entomologist, conservationist and Pulitzer Prize winning author – has this vision and believes that it can be accomplished within the next 50 years. Not only can it be accomplished, but it must be in order to thwart the ongoing sixth mass extinction event. To be precise, half the planet must be set aside, restored to its natural state, and protected in perpetuity. A series of large parks connected by continuous corridors – or “Long Landscapes” – is the way Wilson and other conservationists insist this must be done. Tony Hiss explores the “Half Earth” concept in a feature article in the current issue of Smithsonian entitled, The Wildest Idea on Earth (the online version is entitled, Can the World Really Set Aside Half of the Planet for Wildlife?).

Hiss, accompanied by Wilson, visits three locations in North America where this vision is playing out. Their first stop is Nokuse Plantation in the Florida panhandle, where businessman, M.C. Davis, has purchased tens of thousands of acres with the intention of restoring them to native longleaf pine forests, a plant community that has been reduced by 97% due to human activity. Intact longleaf pine forests are incredibly diverse – as many as 60 different species of living things can be found in one square yard – so protecting and restoring them is an ecological imperative.

Longleaf Pine, Pinus palustris (photo credit: wikimedia commons)

Longleaf Pine – Pinus palustris (photo credit: wikimedia commons)

Later, Davis flies Hiss and Wilson to New England in his private jet. There Hiss discovers a seemingly accidental series of connected natural and restored landscapes nearly 200 miles in length. This corridor, and the land that surrounds it, highlights the need for private land owners to be on board with the Half Earth vision, setting aside their land for conservation in exchange for tax breaks and other incentives.

The importance of private land owners cooperating with this vision comes into play again when Hiss visits the Flying D Ranch near Bozeman, Montana. This 113,613 acre ranch (just a small fraction of the land owned by Ted Turner) is a private ranch that “promote[s] ecological integrity” – it is a wildlife refuge that also turns a profit. Fortunately, the “D” sits within larger wildlife corridor projects – Yellowstone to Yukon and Western Wildway Network – highlighting Wilson’s vision of current sanctuaries being incorporated into larger networks of protected lands.

Hiss notes that as these three projects grow and connect to “the great, unbroken forests across all of northern Canada,” North America will become enclosed in “Long Landscapes” with “additional and more inland routes to be added later.” The sooner these corridors and parks are developed the better, because as global climate changes, species will need to move north, south, east, or west as their ecological and biological needs dictate.

It seems a lofty goal. Humans, after all, have spread themselves across the entire planet, modifying every environment as they go – oftentimes to an irreparable extreme. But knowing this, and recognizing that we are only just beginning to feel the effects of climate change, drastic measures to preserve what is left of this planet’s biological diversity become imperative. Hiss’s article is encouraging in this regard. Yes, the places he visited were confined to North America. A more accurate picture could be constructed by incorporating greater international diversity. However, most promising is that the people he talked to were not political figures. Most of them weren’t even professional scientists. They were businessmen, working people, land owners, citizen conservationists. Wealthy, yes. But people who, at some point in their life journeys, saw a need and wanted to help. The story of M.C. Davis illustrates this best of all. If the information is put out there in a manner that people can relate to, they will latch on to it and offer assistance. For all whose goal is to protect half of the earth (or even just some small portion of it) for the sake of non-human life, this article should give some hope.

Tree growing along a creek bed at The Nature Institute, a privately owned nature preserve in Godfrey, Illinois

Tree growing along a creek bed at The Nature Institute, a privately owned nature preserve in Godfrey, Illinois