Recently, scientists have struck back against one pest in particular, the Princeps (Papilio)  demoleus, a caterpillar with a taste for limes, and they have done so without the use of traditional pesticides or poisons.  Instead, using research first pioneered back in 1998 by Bruce Stevens and his colleagues at the University of Florida, they are exploring a green alternative that disrupt the insect’s ion channel, blocking its nutrient absorption and starving it.

What is the miracle “pesticide”? An amino acid. Methionine, which humans cannot live without, kills the larvae of the Citrus Swallowtail, as well as any invasive larvae with an alkaline intestine. Because it is not toxic to humans, mammals, or birds, or to the citrus it coats, methionine offers an environmentally friendly alternative to conventional pesticides, which are noxious to bugs and humans alike. Furthermore, because the amino acid is a biodegradable nitrogen source, if it reaches the ground it can serve as a cheap fertilizer for the very plant it protects.
Unfortunately, because the Citrus Swallowtail is invasive, researchers cannot test their amino acid defense against it directly, as bringing it into the country would violate laws regulating the import of dangerous species. In its place they have substituted the Heraclides (Papilio) cresphontes, or Giant Swallowtail. Because of its close genetic relationship to the Lime Swallowtail, as well as its similar appetite, digestive tract, and morphology, the insect has been pressed into service as a surrogate for its unlawful cousin.

Experiments conducted at the University of Florida have demonstrated that the methionine pesticide is 100 percent effective against Giant Swallowtails, killing all targeted larvae in no more than 72 hours. And because the Lime Swallowtail has not yet reached Floridian shores—at present it dwells in the Caribbean—the citrus industry, which the insect potentially could devastate, can be confident that when the invader comes, as they all eventually do, scientists will meet it with a fresh crop of tainted limes. The bugs will dine once on the delicious fruit, and then never again.

Discussion Question: Compare and contrast the advantages and disadvantages of using traditional pesticides as opposed to methionine to protect lime trees.

News Article: http://www.sciencedaily.com/releases/2012/01/120117145101.htm
Journal Article: http://www.bioone.org/doi/abs/10.1603/EC11132

Image Source: http://en.wikipedia.org/wiki/File:Limes.jpg

These scientists set out to “estimate loss of genetic diversity by loss of habitat” for different plant species “under different climate scenarios”. After analyzing nearly 10,000 samples from 27 plant species in Arctic environments of central Europe, it was shown that those species that used wind and birds for seed dispersal will preserve greater genetic diversity in a warmer climate than species that have more limited seed dispersion.  Additionally, the longer lifespan of species such as trees and shrubs are able to disperse their seeds more productively than shorter-lived species, such as herbs.

Genetic variation, in short, is essential for adaptation during a changing climate. Seed dispersion is one factor that will determine how various plant species fare with the upcoming climate changes. Some species may lose up to 80% of their habitat but will still  maintain most (90%) of their genetic diversity.  Others will lose 50% of their genetic diversity when their habitat is reduced by 65%.

These new findings will have important effects on the International Union for Conservation of Nature (IUCN) Red List that identifies threatened species. With future climate changes, this list will grow extensively.

Discussion Question: What are some other factors, in addition to seed dispersion, that could have an important impact on the survival fitness of Arctic plant species?

Also, how do you think the criteria of which plants make the Red List will be affected with these new findings?

News Source: http://www.sciencedaily.com/releases/2012/01/120117143758.htm
Journal Source: http://rspb.royalsocietypublishing.org/content/early/2012/01/03/rspb.2011.2363

Image Source: http://www.farnorthscience.com/wordpress/wp-content/uploads/2007/06/svalbardplants.jpg

There are, however, “fertilizers” tailored specifically to release phosphorous to plants: fungi, specifically arbuscular mycorrhizal, which furnish plants with the scarce nutrient–for a price. Arbuscular mycorrhizal (AM) fungi and plants share a symbiotic relationship in which both parties benefit. AM fungi, with their long filaments, are efficient and capable collectors of phosphorus, even in nutrient-poor soil, and they willingly trade the phosphorus they absorb with their plant hosts in exchange for sugars, which plants readily manufacture through photosynthesis.

Some details of the symbiosis were already well known to scientists when Franziska Krajinski and her colleagues at the Max Planck Institute began their research on plant-fungi relationships. Certain cells in the plant, for example, manufacture protein complexes through which the phosphorous and sugar molecules move from plant to fungus; in cells colonized by AM fungi, the genes that encode for these proteins are well expressed.

What the team did not expect to find, however, was the reprogramming they discovered in cells adjacent to or even just near the colonization sites. As first author of the study Nicole Gaude explains, by encoding for the transport proteins, these cells “are preparing themselves for an imminent colonization by the fungus.” Cells, then, activate specific genes–those that facilitate the symbiosis–“even before symbiosis is physically established.”

Discussion Question: Describe some ways in which symbiotic relationships can benefit agriculture.

News Article: http://www.sciencedaily.com/releases/2011/11/111114133644.htm
Journal Article: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2011.04810.x/abstract

Image Source: http://en.wikipedia.org/wiki/File:Arbuscular_mycorrhiza_microscope.jpg

Equipped with a simple and reliable means for measuring past fluctuations in climate–tree rings–scientists extracted evidence from the spruce population in Alaska’s Firth River area, at the border where forest meets tundra. They then combined their data with information gathered during an earlier survey of the Arctic National Wildlife Refuge, at the edge of the Alaskan treeline, and from these samples they constructed a climate timeline for the region reaching back nearly a thousand years. What they found in this coldest of habitats surprised them: wide and dense rings, especially in the past century, indicating warm climate and rapid growth. And the rings are getting wider and denser.

For the scientists this result can mean only one thing: as the global climate gets hotter, the treeline  is retreating north, stimulating some species, such as the white spruce, to thrive. Unfortunately, others aren’t so lucky. Satellite images of the vast interior spaces at lower latitudes show broad stretches of dead and dying vegetation–ecosystems in collapse as the rising temperatures strain sustainability there.

One long-term consequence of these changes, according to the authors, lies in the future role these growing arctic populations will play in regulating levels of carbon dioxide in our planet’s atmosphere–an uncertain but critical variable. Will the novice flora adequately fulfill this role? We shall soon find out.

Discussion Question: Discuss the advantages and disadvantages of a thriving white spruce population in the Alaskan tundra as global temperatures increase.

News Article: http://www.sciencedaily.com/releases/2011/11/111110130106.htm
Journal Article: http://iopscience.iop.org/1748-9326/6/4/045503/

Image Source: http://en.wikipedia.org/wiki/File:Picea_glauca_Fairbanks.jpg

When Heald and anthropologist Susannah Chapman initially set out, they fully expected not to refute but to confirm the persistent myth that crop diversity fell throughout the twentieth century. Heald admits, “we came to this with the exact same preconceptions as everyone else.” And why wouldn’t they? We hear the story everywhere: in conversation, in the media, in public debates on industry and the environment. We even see it in our grocery stores, where any customer hungry for more than the typical red apple is likely to be disappointed. According to Heald and Chapman, all these sources of misinformation fuel our conviction: we harvested our resources sterile, or at least boring.

Not so, argue the researchers. “Overall varietal diversity of the $20 billion market for vegetable crops and apples in the U.S. actually has increased over the past 100 years.” On the evidence of forty-two vegetable crops from 1903 to 2004, they found that, contrary to an annual impoverishment of diversity, varieties increased in the twentieth century. How? Imports. Specifically, individuals–immigrants–bringing new seeds, stocked with “new germplasm,” furtively adding to the market’s diversity by introducing new crop strains. In fact, approximately forty percent of the total diversity came from immigration–“off-the-grid seed savers, small farmers and local gardeners preserving and innovating,” Heald clarifies. By contrast, they found that gains from patents comprised less than three percent of the growth, with biotechnological gains practically non-existent, at one percent.

For Heald and Chapman, the implications are twofold. First, because the myth is just that, the argument over whether patent and biotechnological intervention bolsters or blunts crop diversity is moot. As Heald states bluntly, “both sides are wrong”–economists urging the vital influence of patent law on plant diversity and ethno-botanists vilifying patents as the agent of crop exhaustion. Crops were not impoverished, and patents had little to do with it. Second, “a very efficient market for diversity” can emerge “in the absence of significant legal regulation.” On first consideration, both implications may seem remote. But remember them the next time you visit your local grocery store and lament its poor produce selection. Just because you don’t see the diversity, Heald cautions, doesn’t mean it isn’t there.

Discussion Question: What other commonly believed environmental narratives may be unfounded or mistaken?

News Article: http://www.sciencedaily.com/releases/2011/11/111102161301.htm
Journal Article: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1928920
Image Source: http://en.wikipedia.org/wiki/File:Apples_supermarket.jpg

The proposed solution consists of various components. One is to convert desert landscapes to grow viable vegetation. Many parts of the world, including central Asia and the Sahara Desert, are not compatible for growing plants. But if we convert these barren lands to forests, we can reduce carbon dioxide in the atmosphere.  Another component of the solution involves conserving fresh water by using recycled low quality water for irrigation instead. Lastly, the researchers had to find a plant that could survive in a harsh desert environment. They found that tamarix (botanical genus) did the trick. These plants can be used to produce renewable energy.

This solution has been implemented in Israel’s Aravah Desert successfully and therefore researchers believe it also has potential to work over a larger land area such as the Sahara Desert. This fresh new approach will help in the mass production of bio fuels as well as save agricultural land that is needed for food production.
Discussion question:  What problems could occur if desert landscapes are converted to forests? How would this impact native species living in the desert?

News Article: http://www.sciencedaily.com/releases/2011/10/111026143809
Press Release: http://www.aftau.org/site/News2?page=NewsArticle&id=15427

Image source:  http://en.wikipedia.org/wiki/File:Libya_4985_Tadrart_Acacus_Luca_Galuzzi_2007.jpg

Through their research on the relationship between wasps and fig plants, researchers from the Smithsonian Tropical Research Institute have found that figs punish wasps that fail to pollinate the plant, and this punishment may be critical to maintain the 80-million-year-old arrangement. Figs punish a “cheater” wasp by dropping the unpollinated fruit that houses the wasp’s developing young offspring.
This prevents wasps from harvesting the benefits of using the fig as a nest without reciprocating the favor by pollinating the fig. To study this relationship, either pollen-free or pollen-carrying wasps were introduced into a mesh bag that contained an unpollinated fig. It was found that often, trees dropped unpollinated figs before the young wasps could mature because the wasps, trapped in the bag, could not pollinate the figs.

Interestingly, it was observed that less cheating was observed in plants where the sanctions or punishment was stronger. This is similar to what we observe in our world – people are less likely to commit crimes when the punishments are harsher.

Discussion Question: How do you think a relationship like this came about 80 million years ago? Do you think that time has changed this relationship? If so, how?

News Source: http://www.sciencedaily.com/releases/2010/01/100114143513.htm
Press Release:http://www.stri.si.edu/english/about_stri/media/press_releases/PDFs/STRI-PR10_Edited_Fig-Wasp_release3_2.pdf

Image source: Marcos Guerra – http://www.sciencedaily.com/releases/2010/01/100114143513.htm

Water molecules hold on to certain types of pollen and drag them up into the clouds. These pollen particles then become the centers upon which ice crystals form. These tiny particles can cause an increase in the temperature at which cloud water freezes by up to 18˚C. Increased ice formation then increases cloud reflectivity and increases the possibility that droplets will become heavy enough to fall as rain. As moisture falls out as precipitation, clouds become thinner and allow more sunlight to reach the Earth’s surface.

Called nucleation, this ice crystal formation is caused by water-soluble chemicals on pollen surfaces. It was found that when pollen grains were removed, temperature changes still occurred. This finding suggests that there it is not the plant pollen itself that causes nucleation to occur. The water-soluble chemicals on pollen surfaces must have been left behind and caused the changes in freezing point.

Discussion question: Are there any ways that you can see this discovery being put to beneficial use in an industrial setting? Where else might the chemicals that are responsible for this phenomenon be put to use?

News article: http://www.sciencenews.org/view/generic/id/335144/title
Journal article: http://www.atmos-chem-phys.net/11/1/2011/acp-11-1-2011.html

Image source: Tim Axford – http://www.timaxford.com/index.php?showimage=40

Led by Juan Jose Martinez Sanchez, researchers at the Polytechnic University of Cartagena have set out a recovery plan for this species that looks at the most critical aspects of the plant’s life cycle. This includes the plant’s natural flowering and fruiting times, its reproductive success, and the patterns of recruitment. However, because the reproductive success is low and its rate of mortality is high, the scientists have placed an even stronger significance on managing the plant’s environment.

In addition, Martinez Sanchez explains that this small and fragmented population of legume is a perennial plant with a very short life cycle. As a result, the urgency of conducting more tests to understand and revive the plant becomes important. But, this importance, Martinez Sanchez claims, “lies in preserving biodiversity as a whole, not as a collection of isolated components.”

Discussion Question: Describe some possible internal and external factors that could have contributed to the plant’s disappearance for nearly a century.

News article: http://www.sciencedaily.com/releases/2011/10/111013103642.htm
Journal article: http://www.sciencedirect.com/science/article/pii/S0367253010001647

Picture: http://en.wikipedia.org/wiki/File:Astragalus_nitidiflorus.jpg

So is there a relationship between how economically the animal feeds and the type of nectar it selects as a meal? If there is, how do the animals know which flowers to frequent? In the melee of a spring afternoon, the meadow air riotous with life, the lowly bee finds many flowers–and opposes many competitors. The bee’s choice of flower, it turns out, is as simple as, well, complicated physics. It–or rather its instincts–calculates what mathematicians call optimization, or bang-for-buck, for each source of nectar. Some nectar is very viscous and rich, an excellent food, but only for those with the right tool. (Consider drinking honey through a small straw.) Other nectar is thin or dilute, and for occasions such as these, humans invented straws, because lapping at the solution with your tongue, as dogs do, simply isn’t efficient.

And because bees are stuck with their tongues, not straws, they avoid the thin nectar and head straight for the gooey stuff, ideal for probing. Butterflies, by contrast, with their fabulous tubes, skip the heavy load and opt for the lighter nectar. So it is the ratio of sugar to water in a flower’s nectar that attracts its optimal pollinator. A higher sugar to water ratio increases viscosity, and a lower one decreases viscosity of the nectar. And although it may not be a deep thinker, the bee knows it doesn’t want to die for some runny bug juice.

Thus, based on its individual feeding style, each pollinator gravitates toward the nectar that it can obtain with the greatest efficiency. Animals that feed by dipping their tongues into nectar choose nectar that is 50-60% sugar and can feed most efficiently on nectar with a 52% sugar concentration. Animals that feed by suction choose nectar that is 30-50% sugar can feed most efficiently on nectar with a 33% sugar concentration. Credit a team of MIT researchers for the insight. They hope next to apply their work on optimization to a lizard that drinks through its skin!

Discussion Question: What other mathematical concepts might be used to better explain species behavior?

News Article: http://www.sciencedaily.com/releases/2011/10/111012124147.htm
Journal Article: http://www.pnas.org/content/108/40/16618

Image Source: http://en.wikipedia.org/wiki/File:Osmia_ribifloris_bee.jpg
>150KB but <1.5MB