Plant Community A Weak Predictor Of Bee Community

Native bees -- often small, stingless, solitary and unnoticed in the flashier world of stinging honeybees -- are quite discriminating about where they live, according to U.S. Geological Survey research.

The study found that, overall, composition of a plant community is a weak predictor of the composition of a bee community, which may seem counterintuitive at first, said USGS scientist and study lead Ralph Grundel. This may be because specialized plant-bee interactions, in which a given bee species only pollinates one plant species and that plant species is only pollinated by that bee species are not common. More common is for a plant species to be pollinated by many pollinator species and each pollinator species pollinating many species of plants.

Given this complex network of interaction between plants and their pollinators, it is not surprising that knowing which plants occur in an area does not necessarily allow us to predict which bees will occur in that area, Grundel said.

Unraveling such mysteries surrounding how native bees inhabit and use different habitats is especially essential now -- the National Academy of Sciences has reported that not only is there direct evidence for decline of some pollinator species in North America, but also very little is known about the status and health of most of the world's wild pollinators. Yet without them, the ability of agricultural crops and wild plants to produce food products and seeds is jeopardized.

"The issues facing honeybees introduced pollinators whose populations are spiraling downward, means that it is even more vital to understand the role of native bees as pollinators and how they divide up and use a landscape," said Grundel.

Many studies have been conducted to determine how a variety of animals -- birds, mammals, and reptiles, for example -- use their native landscapes, but few such studies have been undertaken for native bees. "That's why this type of study is fundamental for enhancing our understanding of native bee distribution," Grundel said. "Our research findings clearly reveal that maintenance of a diverse and abundant bee community requires that managers consider a suite of local and landscape characteristics and management actions."

Grundel and his colleagues wanted to find out if the kinds of plants that live in different habitats can predict what kinds of bees will be there or if other factors -- such as soil type, tree density or even fire -- are more important. To do this, the team surveyed landscapes and collected and identified nearly 5,000 native bees representing at least 175 species in five kinds of habitats at Indiana Dunes National Lakeshore and nearby natural areas around northwestern Indiana. These habitats ranged from dense forests to open fields.

"We had suspected that the closer our collecting sites were to each other the more similar the bees communities we found would be -- but we were wrong," Grundel said. "In fact, mere physical proximity wasn't a very good predictor of how similar bee communities at different sites would be to each other. Instead, local factors -- and even the micro-habitats that we often ignore -- are really important in determining what kinds of bees use an area."

Because many native bees are ground- and cavity-nesters, the scientists weren't surprised to find that an abundant supply of dead wood, such as woody debris and dead tree limbs, was essential in determining what kinds of bees lived where. They were surprised, however, at how important other factors were, including bee preferences for specific soil characteristics and for areas that had burned in the previous two years.

Bee abundance -- how many bees were captured at a site -- was lower in areas with a dense tree canopy and higher if a fire had occurred recently in the area. Bee diversity -- the number of different kinds of bees -- was higher in areas with less tree canopy, but with a higher diversity of flowering plants and an abundance of nesting resources, such as woody debris.

The presence of suitable nesting material was at least as important in determining how many types of bees might use a site as was diversity of plants, which provide nectar and pollen to the bees. The composition of an entire bee community was linked to higher plant variety, less canopy cover and soil characteristics that may be best-suited for nesting.

The study found that specialist bees -- those picky native bees that gather pollen from only a few kinds of plants -- were more likely to live in open areas than areas with a higher density of trees.

"Specialist bees, not surprisingly, were also more associated with the presence of native plants in the areas, but a lot of these native plants were more likely to occur in disturbed areas, including areas that had recently been burned and, somewhat to our surprise, residential areas where soil disturbance is commonplace," Grundel said.

However, specialist bees were often rarer and mainly used open habitats, such as grasslands and savannas. According to a 2005 study, said Grundel, such open Midwest habitats are today perhaps the most poorly conserved habitats on the planet, causing concern about long-term conservation of such bee species.

"At several locations around the world, specialist bumblebees living in plant rich areas, such as these open habitats, have declined significantly," Grundel said. "Similar bumblebee declines have been documented in the Midwest U.S. Documenting how diet breadth, rarity and habitat use are related is important for understanding such patterns of decline and was one of the main objectives of our study. We collected six bumblebee species in our study while a 1930s study in this area collected twelve species. Four of the species we did not find in our study have been identified as bumblebees of special concern due to their disappearance from sites across the Midwest."

USGS researchers in Indiana and Maryland are following up on this research with a recently initiated study examining how native bee populations across the national park system might be affected by climatic variation.

Ralph Grundel, Robert P. Jean, Krystalynn J. Frohnapple, Gary A. Glowacki, Peter E. Scott, Noel B. Pavlovic. Floral and nesting resources, habitat structure, and fire influence bee distribution across an open-forest gradient. Ecological Applications, 2010; 20 (6): 1678 DOI: 10.1890/08-1792.1

Source: United States Geological Survey.

Optimizing Biogas Production From Livestock Manure

A team of researchers from the Institute for Animal Science and Technology of the Universitat Politècnica de València (Spain) has developed a project that combines pig slurry and agricultural by-products to optimize biogas production. Thus, it manages to add value to farms' excess slurry and offers a sustainable use to some of the by-products from the fruit and vegetable processing industry.

The project's main researchers María Cambra-López, Verónica Moset and Pablo Ferrer are agronomists coordinated by Prof. Antonio Torres. They explain that pig farms generate large amounts of slurry, consisting mainly of animal excreta, cleaning water and feed residues, the management of which normally consists of storing it in pools and then using it as fertilizer in agricultural fields.

However, because of the manure's properties, rich in nutrients -such as nitrogen and phosphorus- and organic matter, it can cause pollution to soil, water and atmosphere as a result of excessive accumulation of these nutrients in soil and water and the emissions of greenhouse gases and ammonia.

In areas such as the north of Castellón and inland Valencia where there is a high concentration of pig production, there is not enough agricultural land to absorb the large volume of slurry produced on local farms. Furthermore, the transport of this slurry to other areas involves extra costs -because of its high water content- that farmers are not willing to accept, says María Cambra-López.

Therefore, the team of Spanish researchers has studied the combined processing of pig slurry and agricultural by-products to produce biogas, in order to provide a sustainable use for these products. Moreover, this combination can avoid undesirable environmental side-effects and the project offers to turn pig slurry into a valuable product: energy.

Verónica Moset explains that slurry on its own does not produce much energy, and therefore a biogas plant is not a profitable business for farmers. However, if we combine it with certain fruit and vegetables from the region that are not good enough to sell, we can increase the methane level and this way produce biogas cost-effectively.

So far, researchers have tested in vitro the combination of pig slurry with peppers, tomatoes, peaches and kaki to study their potential to produce biogas and the optimal combination of both substrates. The engineers found that peppers increased by 44% methane production compared with slurry-only; tomatoes, by 41%; peaches, by 28%, and they did not observe any difference in methane production using kaki.

With this encouraging data, Pablo Ferrer says that they will carry out trials in large-scale digesters and simulate the real biogas production process using peppers, tomatoes and peaches. Researchers believe that in another year they will be able to offer results and could transfer the technology to real-scale centralized biogas plants.

Thus, the benefit of this project is extensive and varied. On the one hand, it reduces the emission of methane during slurry storage, a highly polluting gas that has a higher greenhouse effect than CO2. On the other, it provides farmers with an alternative use for pig slurry as well as an additional income.

The researchers are also working closely with the Centre for Animal Research and Technology of the Valencian Institute for Agricultural Research (IVIA) to evaluate the effect of addition of agricultural by-products such as rapeseed oil, orange pulp or rice husk in pig feed, on methane emissions from manure which could therefore increase biogas production.

This project is funded by the Foundation Agroalimed of the Regional Department of Agriculture, Fisheries and Food.

Source: Asociación RUVID, via AlphaGalileo.

Lyme Disease In Central Illinois: Well Adapted

A new study offers a detailed look at the status of Lyme disease in Central Illinois and suggests that deer ticks and the Lyme disease bacteria they host are more adaptable to new habitats than previously appreciated.

Led by researchers at the University of Illinois, the study gives an up-close view of one region affected by the steady march of deer ticks across the upper Midwest. Their advance began in Wisconsin and Minnesota and is moving at a pace of up to two counties a year in Illinois and Indiana.

Today the deer tick is established in 26 Illinois counties, up from just eight in 1998, said Illinois Department of Public Health entomologist Linn Haramis. Reports of human Lyme disease cases in the state have more than tripled in the same period, he said.

"We've had several years in a row where we've had over 100 cases, up from about 30 per year more than 10 years ago," Haramis said. "It's not a huge increase, but it's been steady and there's an upward trend."

Deer ticks are known to do best in forested areas, where they can readily move from small mammals (which provide their first meal) to moist leaf litter on the forest floor, and then to deer, on which they mate. Deer ticks do not pick up the Lyme infection from deer, said Jennifer Rydzewski, who completed her master's degree with the study in the department of natural resources and environmental sciences at the University of Illinois.

"The deer tick will feed on a variety of mammals, birds and even reptiles," she said. "But Borrelia burgdorferi, the bacterium that causes Lyme disease, replicates really well within white-footed mice, so white-footed mice are the main reservoir that passes that bacterium on to the immature ticks that are feeding on it."

White-footed mice also are forest dwellers. Prior to the new study, little was known about whether, or how, Lyme disease persists in other habitat types.

To determine if Lyme disease had gained a foothold in the patchwork of forests, farms and prairies of Central Illinois, researchers trapped small mammals in Allerton Park, a 1,500-acre (600-hectare) natural area in Piatt County. They focused on four habitat types: young forest, mature forest, a flood plain and a 30-acre (12-hectare) patch of prairie surrounded by woods and agricultural fields.

The researchers removed deer ticks from the mammals they trapped and tested the ticks for Lyme disease.

They found that the immature forest and the prairie hosted the highest percentage of deer-tick-infested mammals, the highest number of ticks per mammal trapped and the highest rates of ticks infected with Lyme disease of the four habitat types evaluated.

"The highest prevalence of B. burgdorferi infection was found (in deer tick larvae) from the prairie (27 percent) followed by the young forest (15 percent), the mature forest (6 percent) and the flood plain (6 percent)," the researchers wrote.

"Interestingly, all of the positive ticks from the prairie were from prairie voles, not the typical white-footed mouse," Rydzewski said. There also were many more ticks per animal on the prairie voles than on the white-footed mice of the forest, she said.

This is the first study to report evidence that the prairie vole may potentially serve as a competent reservoir host for the Lyme disease bacterium, B. burgdorferi, said Nohra Mateus-Pinilla, a wildlife veterinary epidemiologist at the Illinois Natural History Survey who led the study with Rydzewski and natural resources and environmental sciences emeritus professor Richard Warner. (The Survey is a unit of the Prairie Research Institute at Illinois.)

"The fact that we found tick larvae feeding so prominently on prairie voles and those ticks were infected and hadn't had a chance to feed on anything else is a very strong indicator that we are dealing with a different reservoir of Lyme disease that deserves more attention," Mateus-Pinilla said.

The researchers hypothesize that when newly hatched ticks find themselves on the prairie, they latch on to the first small mammal that comes along, which in most cases is a prairie vole (white-footed mice prefer the forest). The abundance of prairie voles in the prairie is much lower than that of the white-footed mice in the forest, so more tick larvae and nymphs end up on the same few prairie voles. Since the number of ticks per animal is higher on the prairie, the likelihood of infection is higher there as well.

"The landscape of Illinois, especially the northern and central area, is very fragmented with agricultural and other development, so there aren't really big continuous areas that are forested," Rydzewski said. "And so maybe these ticks are finding new habitats to establish themselves in because of the lack of previous habitats."

"What's exciting about the new findings is that we are dealing with potentially new mechanisms of disease transmission that we just have not explored and perhaps we do not understand," Mateus-Pinilla said. "We need to think outside of what we already know about Lyme disease transmission."

The new study appears in the journal Vector-Borne and Zoonotic Diseases.

Researchers from the U. of I. department of pathobiology and Michigan State University also contributed to this study.

Source: University of Illinois at Urbana-Champaign.

What Humans Should Learn From Plants Disease Fighting Mechanisms

Avoiding germs to prevent sickness is commonplace for people. Wash hands often. Sneeze into your elbow. Those are among the tips humans learn.

But plants, which are also vulnerable to pathogens, have to fend it alone. They grow where planted, in an environment teeming with microbes and other substances ready to attack, scientists note.

Now, researchers are learning from plants' immune response new information that could help them understand more about humans' ability to ward off sickness and avoid autoimmune diseases.

In the latest issue of the journal Science, Texas AgriLife Research scientists report their findings of a "unique regulatory circuit" that controls how a plant turns on and off its immune sensor.

"Plants and animals live out their lives mostly in good health, though they may have been subjected to a lot of pathogenic microbes," said Dr. Libo Shan, AgriLife Research plant molecular biologist and lead author for the journal article. "Scientists all around the world have been interested in how a healthy host can fend off invasions of pathogens and turn off the defense responses promptly once the intruder risk factors are decreasing."

The research team found a "unique regulatory circuit" in which BAK1, a protein involved with cell death control and growth hormone regulation, recruits two enzymes -- PUB12 and PUB13 -- to the immune sensory complex and fine-tunes immune responses.

Basically, the surface of plant cells has sensors that sense microbial invasion. One of the best understood plant receptors is FLS2, found in the common laboratory plant Arabidopsis.

FLS2 could sense the bacterial flagellin, which is a part of the flagellum, or tail-like projection on cells which help it to move. When FLS2 perceives flagellin, a series of "evolutionary conserved immune responses" is activated to fend off bacterial attack, Shan said.

But the immune response can not stay activated or the plant will stop growing and producing.

"To avoid detrimental effects of long-lasting immune activation, plant and animal hosts need a way to switch the activation off," she noted. "How that can be has been a mystery to scientists."

The team discovered that the flagellin perception recruited PUB12 and PUB13 to the receptor FLS2 complex.

Those two enzymes could add a biochemical signature tag, ubiquitin, to the FLS2 receptors which inform sells to degrade the immune senors, she added. As a result of these actions, immune signaling decreased.

Knowing how immune signaling works may help researchers devise ways to help plants and animals -- including humans -- regulate their immune systems. Shan said the mechanism her lab discovered is very broad in that it can be found in both plants and animals.

"We needed to understand the mechanism so that we can regulate it better," she said. "The host needs to know when the signal is triggered (to fight off a pathogen). Then the immune response needs to go quickly up and then back down when it is no longer needed."

Shan believes that this ability could lead to cures, rather than medical relief, from an assortment of ailments including allergies and autoimmune diseases.

"Plants have figured out how to survive in terms of disease and pest resistance," she added. "And what we learn from them at the molecular level might help us understand animal pathogens better."

Dongping Lu, Wenwei Lin, Xiquan Gao, Shujing Wu, Cheng Cheng, Julian Avila, Antje Heese, Timothy P. Devarenne, Ping He, Libo Shan. Direct Ubiquitination of Pattern Recognition Receptor FLS2 Attenuates Plant Innate Immunity. Science, 2011; 332 (6036): 1439-1442 DOI: 10.1126/science.1204903

Source: Texas A&M AgriLife Communications.

New Finding In Plant Cell Membranes Signaling

Every living plant cell and animal cell is surrounded by a membrane. These cellular membranes contain receptor molecules that serve as the cell's eyes and ears, and help it communicate with other cells and with the outside world.

The receptor molecules accomplish three basic things in the communication process: 1) recognize an outside signal, 2) transport that signal across the cell's membrane and 3) initiate the reading of the signal inside the cell and then initiate the cell's response to that signal. These steps are collectively known as transmembrane signaling.

Transmembrane signaling in animal cells has been significantly more studied and observed than that in plant cells. But now, with support from the National Science Foundation, researchers from Joanne Chory's laboratory at the Salk Institute have published new observations about transmembrane signaling in plants; their paper appears in the June 12, 2011, advanced online edition of Nature.

Transmembrane signaling in a plant cell aided by a steroid. (Credit: Zina Deretsky, National Science Foundation).

According to the study, transmembrane signaling mechanisms used by plants differ from those used by animals. Specifically, Michael Hothorn of the Salk Institute reports that a small steroid molecule on the outside of the plant cell assists in the transmembrane signaling process. By contrast, this sort of molecule and its receptor is generally located inside the nuclei of animal cells.

While studying transmembrane signaling in plants, Hothorn and colleagues observed the steroid, shown in yellow, attach to a membrane-bound receptor, shown in blue. This attachment enabled the steroid's counterpart--a co-receptor protein, shown in orange--to bind to the blue receptor. Once bound, the orange co-receptor and the blue receptor become glued together by the yellow steroid, allowing their intracellular domains to touch and initiate communication.

In the case observed by Hothorn, transmembrane signaling initiated plant growth.

Michael Hothorn, Youssef Belkhadir, Marlene Dreux, Tsegaye Dabi, Joseph. P. Noel, Ian A. Wilson, Joanne Chory. Structural basis of steroid hormone perception by the receptor kinase BRI1. Nature, 2011; DOI: 10.1038/nature10153

Source: National Science Foundation.

Top Dirty And Clean Foods To Buy

The list of clean and dirty foods, percentage of pesticides in them, is out as published by Environmental group.

Four New Viruses Affecting Bees Identified

A 10-month study of healthy honey bees by University of California, San Francisco scientists has identified four new viruses that infect bees, while revealing that each of the viruses or bacteria previously linked to colony collapse is present in healthy hives as well.

The study followed 20 colonies in a commercial beekeeping operation of more than 70,000 hives as they were transported across the country pollinating crops, to answer one basic question: what viruses and bacteria exist in a normal colony throughout the year?

The results depict a distinct pattern of infections through the seasons and provide a normal baseline for researchers studying a colony -- the bee population within a hive -- that has collapsed. Findings are reported in the June 7 issue of the online journal PLoS ONE, published by the Public Library of Science.

The study tracked 27 unique viruses that afflict honey bees, including four that previously were unknown and others proposed as causes of the Colony Collapse Disorder that has been wiping out colonies for the past five years, according to senior author Joe DeRisi, PhD, a Howard Hughes Medical Institute investigator and professor of biochemistry and biophysics at UCSF.

"We brought a quantitative view of what real migrating populations look like in terms of disease," DeRisi said. "You can't begin to understand colony die-off without understanding what normal is."

Because the colonies in this study remained healthy despite these pathogens, the research supports the theory that colony collapse may be caused by factors working alone or in combination, said Michelle Flenniken, PhD, who jointly led the research.

Working in the lab, from left, are Michelle Flenniken, a postdoctoral scholar, Joseph DeRisi, PhD, a Howard Hughes Medical Institute investigator and professor of biochemistry and biophysics at UCSF, and Charles Runckel, a graduate student. (Credit: Lab photo by Cindy Chew).

"Clearly, there is more than just exposure involved," said Flenniken, a postdoctoral scholar in the laboratory of UCSF microbiologist Raul Andino, PhD. "We noticed that specific viruses dominated in some seasons, but also found that not all of the colonies tested positively for a virus at the same time, even after long-distance transport in close proximity."

Honey bees are critical to U.S. agriculture, which depends upon them to pollinate 130 different crops, representing more than $15 billion in crop value each year and roughly one-third of the human diet, according to the U.S. Department of Agriculture.

For the California almond crop to be successfully pollinated, DeRisi said, roughly half of the honeybees in the country -- about 1.3 million honeybee colonies -- must be in the Central Valley by the first week in February, when the trees begin to bloom. That need is echoed throughout the country, as different crops come due for pollination, resulting in semis traversing the nation for most of the year, each bearing hundreds of hives.

Since 2006, however, the bee industry has reported a mysterious phenomenon involving the sudden disappearance of most of a hive's worker bees, which leaves the queen and young bees without enough workers to support them. The disorder is one factor in the growing decline of U.S. honey bees -- an estimated 30 percent of the population is lost each year and some beekeeping operations cite 90 percent losses, the USDA reports.

Researchers nationwide have identified various possible causes of that collapse, mainly based on pathogens found in the affected hives. While this study did not identify the cause of colony collapse, it did offer a measurement of the normal levels of pathogens.

In addition to viruses, the research revealed six species each of bacteria and fungi, four types of mites and a parasitic fly called a phorid, which had not been seen in honey bees outside California. One of the new viruses, a strain of the Lake Sinai virus, turned out to be the primary element of the honey bee biome, or community of bacteria and viruses.

"Here's a virus that's the single most abundant component of the bee biome and no one knew it was there," DeRisi said, noting that hundreds of millions of these viral cells were found in each bee in otherwise healthy colonies at certain times of the year.

Flenniken jointly led the work with doctoral student Charles Runckel, in DeRisi's lab. The team used a broad range of molecular detection tools for the study, including gene sequencing and a custom-designed microarray to detect insect pathogens. The microarray was designed using the same principles used for detecting human viruses, which DeRisi pioneered with UCSF professor Donald Ganem, MD. It was built in the Center for Advanced Technology on the UCSF Mission Bay campus.

The research was primarily funded by Project Apis m., which includes members of the American Honey Producers Association, the American Beekeeping Federation, the National Honey Board, California State Beekeepers Association and California almond farmers. DeRisi is supported by the Howard Hughes Medical Institute. Flenniken's research was supported by the Häagen Dazs post-doctoral fellowship in honey bee biology, through University of California, Davis. Other funding sources and data can be found in the full paper.

Co-authors include Andino, in the UCSF Department of Microbiology and Immunology; Juan C. Engel, in the UCSF Sandler Center for Drug Discovery and UCSF Department of Pathology; and J. Graham Ruby and Donald Ganem, in the Howard Hughes Medical Institute and UCSF departments of Biochemistry & Biophysics, and Microbiology.

Charles Runckel, Michelle L. Flenniken, Juan C. Engel, J. Graham Ruby, Donald Ganem, Raul Andino, Joseph L. DeRisi. Temporal Analysis of the Honey Bee Microbiome Reveals Four Novel Viruses and Seasonal Prevalence of Known Viruses, Nosema, and Crithidia. PLoS ONE, 2011; 6 (6): e20656 DOI: 10.1371/journal.pone.0020656

Source: UCSF.