Batting a Billion

Did you know that 2011-2012 is the Year of the Bat? Thanks to classic literature and popular culture, bats are thought to be nocturnal, creepy, winged rats. Probably every fear people have concerning bats is based on centuries of myths and misinformation. As part of my what-is-becoming-typical subject introduction I thought I'd give some facts and dispell a few of the myths about bats with a little round of True or False. As I plan to present a paper here and not just a bunch of bat facts I'll try to keep to some of the most popular myths and at the end of this post I'll have some links where you can find out more information.

True or False?: Bats are mammals.

TRUE

Bats are flying mammals belonging to the order Chiroptera. There are more than 1,100 species (that's 1/5 of all mammals!), including the world's smallest mammal, a bat the size of a bumblebee.

True or False?: Bats are blind.

FALSE

Actually many bats have very good eyesight. However, because many species are nocturnal (active at night) they have an extra sense that helps them to navigate and find food: echolocation. They send out sound which bounces back off of objects and creates a sort of map for the bat.

True or False?: All bats feed on blood.

FALSE

Well, mostly. Admittedly there are three species of vampire bat: the Common Vampire Bat (Desmodus rotundus), the Hairy-legged Vampire Bat (Diphylla ecaudata), and the White-winged Vampire Bat (Diaemus youngi); all of which are found in Latin America. But don't worry, they don't require much blood and typically like to feed on livestock. More than two-thirds of bat species are primary predators of night-flying insects, this includes agricultural pests and many insects humans find to be particularly disruptive or annoying. A single bat can eat up to 1,000 mosquito-sized insects in a single hour! The other third of bat species feed on the fruit and nectar of plants. As such, they serve as pollinators and seed dispersers for many plant species. A small percentage are also known to eat fish, frogs, mice, birds and/or other small vertebrates.

True or False?: Bats are found everywhere.

FALSE

Close but no. Bats are a very diverse group that take advantage of a wide variety of habitats, but they do not inhabit extreme desert and polar regions.

True or False?: Bats live in caves.

TRUE

You can find many bat species living in caves. This is because one of the most basic requirements for bat is a safe roost. As such, bats can be found living in almost any conceivable shelter, from caves to buildings to leaf cavities and even in animal burrows. As their habitats shrink, more and more species, and individuals, can be found living in buildings. Building bat houses, the same concept as a bird house, is a backyard conservation technique that is catching on with the public. (Learn how to build you own bat house here: http://www.batcon.org/index.php/get-involved/install-a-bat-house.html)

The questions that I've listed here are not only some of the most popular concerning bats, they are also directly related to today's topic. A new Policy Forum paper published in Science this week takes a look at bat conservation from the aspect of their economic importance.

It is known that White-nose Syndrome (WNS) and the increased development of wind-power facilities are threatening populations of bats in North America. WNS is a fungus (Geomyces destructans) that infects the skin of cave-dwelling bats while they hibernate, particularly around the nose, ears, and wings. It is associated with a high mortality rate and is estimated to have killed over a million hibernating bats in more than 15 U.S. states and 2 Canadian provinces. Little Brown Bats (Myotis lucifugus) are sustaining the highest mortality rates, showing a 93% decline in 23 caves at the epicenter of the WNS outbreak. Other species affected include the Big Brown Bat (Eptesicus fuscus), Northern Myotis (Myotis septentrionalis), Tri-Colored Bat (or the Eastern Pippistrelle, Pipistrellus subflavus), Eastern Small-Footed Myotis (Myotis leibii), and Indiana Bat (Myotis sodalis).

Our growing concerns about climate change mixed with our desire to break our dependance on oil have resulted in the construction of more wind turbines. As a source of alternative energy wind turbines are a wonderful thing. However, for species of migratory tree-dwelling bats they are a flight, and life, hazard. In North America, these species include the Eastern Red Bat (Lasiurus borealis), the Hoary Bat (Lasiurus cinereus), and the Silver-haired Bat (Lasionycteris noctivagans). Other species that are ssusceptible to wind turbines include the Tri-colored Bat (L. subflavus), the Little Brown Myotis (M. lucifugus), and the Big Brown Bat (E. fuscus), species names that should sound familiar after reading about WNS. Included in this list of affected species includes bats with a relatively small range sizes, the Mexican Free-tailed Bat (Tadarida brasiliensis) and the federally endangered Indiana Myotis (M. sodalis). High numbers fatalities in species with small range sizes has a greater impact on the survivability of the species than the same number of fatalities in populous, large-range species. It is still unclear why these species are so susceptible to wind turbines. There is no continental-scale monitoring programs for assessing wildlife fatalities caused by wind turbines, but it is predicted that by 2020 an estimated 33,000 to 111,000 bats will be killed by wind turbines just in the Mid-Atlantic Highlands of the U.S.

This article focuses on these two sources for declining bat populations, leaving out sources such as habitat degradation. The numbers of bat fatalities are, in and of themselves, pretty staggering, but many people in political and policy making positions still consider it an academic interest rather than an economic problem. That is where this article becomes particularly interesting. In fact, the economic consequences of losing so many bats could be substantial. One example the authors use is the Big Brown Bat (E. fuscus). A single colony of 150 bats in Indiana as been estimated to eat nearly 1.3 million pest insects per year. Think about it: That is one relatively small colony of bats eating a whole lot of insects. Other estimates have a single Little Brown Myotis (M. lucifugus) consuming 4 to 8 grams of insects each night. Doesn't sound like much, but if you extrapolate that from one bat to one million bats that is 660 to 1320 metric tons of insects. This is a huge disruption to the population cycles of agricultural pests, and to say that bats are unimportant is just ignorant. 

The paper goes on to discuss the economic importance of bats in agricultural systems, estimating the value of the pest suppression services provided by bats. Previously published estimates have the value at anywhere from $12 to $173 per acre, with a likely value at $74/acre in a cotton-dominated landscape in south-central Texas. The authors here took these values and extrapolated the estimates to the entire United States. They estimated that the value of bats to the agricultural industry at between $3.7 billion and $53 billion per year with a likely value of approximately $22.9 billion per year. This cost does not include any downstream impacts of bat loss such as the impact of pesticides, secondary predation, and the predator release of insect populations.

A figure describing the worth of bats. Yellow being low cost to red being high cost.

 In terms of policy, the authors suggest that wait-and-see approach to the issue of widespread declines of bat population is unacceptable as the life histories of these mammals suggest that population recovery is unlikely for decades or centuries, if at all. They suggest management actions to restrict the anthropogenic spread of WNS, taking additional steps toward developing improved diagnostics to detect early stage infections and fungal distribution, investigating biological or chemical control of the fungus, increasing disease resistance through habitat modification, potentially culling infected bats, altering wind turbine operations during high-risk periods for bats, and continued research into these problems.


Here's the article:
Justin G. Boyles, Cryan Paul M., McCracken Gary F., and Kunz, Thomas H. (2011) Economic Importance of Bats in Agriculture. Science: 332 (6025), 41. (DOI: 10.1126/science.1201366)

GENERAL INFORMATION ABOUT BATS:
Description of bat species from the Smithsonian National Museum of Natural History:
http://www.mnh.si.edu/mna/image_menu.cfm?order=4
Info on bats from the Natural Science Research Laboratory at the Museum of Texas Tech University: http://www.nsrl.ttu.edu/tmot1/ordchiro.htm
The Year of the Bat website:
http://www.yearofthebat.org/
From Boston University's Bat Lab: http://www.bu.edu/cecb/bats/bat-facts-and-folklore/
From the Museum of Palentology at UC Berkeley:
http://www.ucmp.berkeley.edu/mammal/eutheria/chiroptera.html
A list of academic "bat labs": http://www.science.mcmaster.ca/psychology/faurelab/links

BATS AND WIND ENERGY:
From Bat Conservation International:
http://www.batcon.org/index.php/what-we-do/bats-and-wind-energy.html?utm_source=internal&utm_medium=five_icon&utm_campaign=5IBats%2B%26%2BWind%2BEnergy
Bats and Wind Energy Cooperative (BWEC): http://www.batsandwind.org/
Video and information from Boston University about bats interacting with wind turbines:
http://www.bu.edu/cecb/wind/video/
U.S. Department of Interior, US Fish and Wildlife Wind Turbine Guidelines Advisory Committee:
http://www.fws.gov/habitatconservation/windpower/

WHITE-NOSE SYNDROME (WNS):
Buzbee's Bathouse Page:  http://www.batbox.org/
Info from the U.S. Fish and Wildlife Service: http://www.fws.gov/WhiteNoseSyndrome/
From the Organization for Bat Conservation:
http://www.batconservation.org/drupal/white-nose?gclid=CKy6l6rO-6cCFUNl7Aod6R0srw
USGS National Wildlife Health Center WNS Page:
http://www.nwhc.usgs.gov/disease_information/white-nose_syndrome/
The National Speleological Society's WNS Page:
http://www.caves.org/WNS/

BAT CONSERVATION ORGANIZATIONS:
Bat Conservation International: http://www.batcon.org/
Organization for Bat Conservation: http://www.batconservation.org/
Bat Conservation and Management, Inc.: http://www.batmanagement.com/main.html
Lubee Bat Conservancy: http://www.batconservancy.org/
Bat World Sanctuary: https://batworld.org/
Bat Conservation Trust (in the UK): http://www.bats.org.uk/
The Warwickshire Bat Group (UK):  http://www.warksbats.co.uk/
The Norfolk Bat Group (UK): http://www.norfolk-bat-group.org.uk/index.html

(image from discoverlife.org)

The Buzz on the Bees

I was flipping through (or rather, scrolling through) a few popular news sites and noticed that a recent paper published in PLoS ONE has gained some traction. It is a story about honey bees and Colony Collapse Disorder.

The European honey bee (Apis mellifera) is a common pollinator worldwide. You can find them where there are flowers to feed on and suitable hive-building sites. Most of the individuals you see buzzing around your garden collecting pollen are females (workers), the males are significantly bigger and are very few in number. These social insects heat their hives with body heat and cool it by fanning their wings, this way they can live year-round in a place surviving on their honey reserves through the winter.

As you may have guessed by their common name, these honey bees are not native to the western hemisphere. They were brought over by early European colonists for their honey and wax production. Over time, beekeepers have experimented with the about two dozen subspecies, but they've found that Apis mellifera ligustica (a subspecies brought over by early Spanish settlers) is favorable.

Beginning in October 2006, beekeepers started reporting the losses of 30-90% of their hives. Some loss is normal, but this amount is highly unusual. Colony Collapse Disorder (CCD) is the name that has been given to this serious, mysterious die-off of honey bee colonies across the U.S. CCD is characterized by sudden colony death with a lack of adult bees in front of the die-outs. Honey stores and recent brood rearing are often evidenced, and sometimes the queen and a small number of survivor bees remain. Although there have been published incidences of honey bee disappearances - in the 1880's, 1920's, and 1960's - it is unclear if this same phenomena has happened before. Descriptions are similar to CCD but as it is yet unknown what causes CCD it is difficult to tell.

This year, 2010, CCD has once again devastated honey bee colonies in the US, at rates that are potentially higher than the occurrence in 2006-2007. Previous scientific studies, using sensitive genome-based methods, have found small RNA bee viruses and the microsporidia, Nosema apis and N. ceranae in healthy and collapsing colonies alike. However, no single pathogen has been linked to hive losses.

The study published this week in PLoS ONE used mass spectrometry-based proteomics (MSP) to identify and compare proteins from healthy and collapsing honey bee colonies. This particular method revealed two previously unreported RNA viruses, Varroa destructor-1 virus (VDV-1) and Kakugo virus. They also identified an invertebrate iridescent virus (IIV) (Iridoviridae), a DNA virus, and linked it to the CCD colonies. The CCD colonies were found to not only contain  IIV but also Nosema (specifically N. ceranae). The IIV, in particular, is interesting because it was thought until now that small RNA viruses were the cause of bee diseases. The pairing of IIV and N. ceranae and their correlation with CCD colonies suggests that they track each other and they do not occur concurrently in healthy colonies. Laboratory cage trials add more evidence to support this hypothesis.

It is hypothesized that damage to the bees' gut epithelial tissue and other host cells by N. ceranae allows entry to IIV. Or, perhaps, the replication of N. ceranae in honey bee cells may decrease the bees' ability to ward off viral infections. The presence of IIV may prove to be a useful tool in identifying colonies in the early stage of CCD or a possible resistance to the virus in a strong colony. IIV's are not completely unstudied. In fact, a good amount of study has been done on them for use as biopesticides. IIV-3 and IIV-6 have had a complete genome sequencing, and 24 other IIV's have been partially characterized. Viral diseases are currently only manageable rather than curable, with infected bee populations needing culling. Nosema, however, is treatable with current management techniques. Since their pairing suggests increased lethality, disrupting the relationship may be an option to help reduce bee mortality.

You can read the paper here:
Bromenshenk, Jerry J., et al. (2010) Iridovirus and Microsporidian Linked to Honey Bee Colony Decline. PLoS ONE: 5(10): e13181. (DOI: 10.1371/journal.pone.0013181)

Also, here's a NY Times article on the subject:
http://www.nytimes.com/2010/10/07/science/07bees.html

Also, check out these links for more information on Colony Collapse Disorder:
Mid-Atlantic Apiculture Research and Extension Consortium (MAAREC)
United States Department of Agriculture: Agricultural Resource Service
United States Department of Agriculture: National Agricultural Library
The Ohio State University's Agriculture Network Information Center's Bees and Pollination Page

(image from nycgovparks.org)

Cellulotastic

A colony of the fungus Neurospora crassa (left) growing on cellulose and the yeast Saccharomyces cerevisiae. Sugar transporters from Neurospora that have been inserted into the yeast are tagged with green fluorescent protein. (Image: Jamie Cate and Susan Jenkins, UC Berkeley & EBI)

Reseachers at the University of California, Berkeley have been working on how and what yeast can digest. They have taken genes from a grass-eating fungi (Neurospora crassa) and put them into yeast. This new set of genes allows the yeast to produce alcohol from cellulose, a material that is normally indigestible. N. crassa is one of the rare yeasts that can digest cellulose because its preferred diet is fire-damaged plants. The genes were located by doing a genome-wide systems analysis to see which genes are turned on when the fungus grows on cellulose. The researchers were able to locate a family of genes which produces proteins that transport sugars into the Neurospora cell to be used a fuel and some transporters, in particular, that allow the cell to import a few types of cellodextrins (specifically cellobiose, cellotriose, and cellotetraose), simple-ish sugars.

Why should we care what yeast are able to digest? The biofuels industry has been struggling to make cellulosic ethanol economically feasible. Right now the industry is using brewers yeast, the single-celled fungus (Saccharomyces cerevisiae) to turn sugar or other simple carbohydrates into alcohol. So far cellulose has been a bit of a problem as it is a pretty tough molecule; it is composed of glucose (simple sugar) molecules all linked together into long chains. Its a molecule that you can find in abundance in various materials such as corn stalks, leaves and cobs (and the US uses a whole lotta corn!) as well as paper waste or any other plant material. Normally these long chains have to be broken up into smaller cellodextrins by enzymes called cellulases using a method called saccharification. Then another enzyme called beta-glucosidase is added to break down the cellodextrins into their simple sugar components. That's all before the yeast even get introduced to the system! If the N. crassa genes (cellodextrin transporters) can be inserted into the industrial strains of yeast that are currently being used for ethanol production the efficiency of the fermentation process can be greatly improved.

The paper appeared in this weeks ScienceExpress:
Galazka, Jonathan M., et al. (2010) Cellodextrin transport in yeast for improved biofuel production. Science: published online. (DOI: 10.1126/science.1192838)

Here is UC Berkeley's new article about the paper:
http://berkeley.edu/news/media/releases/2010/09/09_neurospora.shtml

A Sparkle Motion

While hugging trees during field work yesterday I was listening to the latest podcast of NPR's Wait Wait Don't Tell Me. Towards the end of the episode they talked/joked about a story about the National Pork Industry and their search for a new slogan to replace the well known "The Other White Meat." This reminded me of a story I had read just that morning in The Washington Post regarding the the case of the National Pork Board v. ThinkGeek Inc (website).

The case involves the website's use of the trademarked slogan "The Other White Meat." According to the letter sent to the website by the lawyers representing the National Pork Board: "We are writing you in connection with your activities at the Web site www.thinkgeek.com, wherein you have been marketing a product called 'Radiant Farms Canned Unicorn Meat' using the slogan 'Unicorn -- the new white meat.' A copy of the Web site page is attached for your reference."

Let me give you a second to read that again and let it really soak in...

Yeah, unicorn meat. Apparently the "meat" in question was a prank product launch for April Fool's Day and is described by the website as "...the sparkling, crunchy, savory meat of today's elite." And ok, I get that the industry is just trying to protect its slogan, but really April Fool's Day + unicorns = not worth the legal expenses.

See the offending website "ad" here:
http://www.thinkgeek.com/stuff/41/unicorn-meat.shtml

and their response to the ordeal:

http://www.thinkgeek.com/blog/2010/06/officially-our-bestever-cease.html

and here's The Washington Post story:
http://www.washingtonpost.com/wp-dyn/content/article/2010/06/22/AR2010062201657.html

Update! The New York Times just posted about this on their Bits Blog:

http://bits.blogs.nytimes.com/2010/06/22/unicorns-theyre-not-the-other-white-meat/

(image from knowyourmeme.com)

Bull City Locovores

Living in Durham, North Carolina I can tell you, there is some yummy yummy food in this city.

"... hundreds of outlying acres of rich Piedmont soil have 'transitioned' from tobacco, and now sprout peas, strawberries, fennel, artichokes and lettuce. Animals also thrive in the gentle climate, giving chefs access to local milk, cheese, eggs, pigs, chickens, quail, lambs and rabbits."

"... a drive around town might yield the smell of clams from the coastal town of Snead’s Ferry, steaming in white wine, mustard and shallots at Piedmont restaurant; pungent spice and sweet fennel from the 'lamby joe' sandwich at Six Plates; and seared mushrooms and fresh asparagus turned in a pan with spring garlic at Watts Grocery."

A lot of that food is obtained locally by many of the most popular restaurants in the area. A new(ish) article in The New York Times highlighted Durham's shift to local foods. This shift is particularly intriguing considering that not all that long ago the area and its farms was focused on the growing, harvesting, selling, and manufacture of tobacco. Many of those tobacco farms have switched to produce or livestock such as cattle and sheep.

"There are still plenty of good places for a barbecue plate, excellent French bistros like Vin Rouge and Rue Cler, and some white-tablecloth dining rooms, both traditional and modern."

"But the most intriguing cooks here have a few things in common: an understanding of how to give a menu a sense of place; a true love of pork and greens in all their forms; and a lack of interest in linens and glassware. Watts Grocery, for example, looks like an upscale sports bar, but it tastes like a Southern-artisanal Union Square Cafe."

Chefs take advantage of the locally grown products by visiting farms and farmers markets. This allows the restaurants and chefs to serve fresh, often organic, foods at very affordable prices.

"The food at Neal’s Deli is resolutely everyday and American — like breakfast biscuits stuffed with egg and sausage — but the eggs are steamed tender with a touch of pepper and parsley, and the wide, crisp biscuits are mixed from high-fat local buttermilk and organic flour from a nearby mill that’s been held by the same family for nine generations. The sausage patty is from Cane Creek
Farm in Alamance County, where Eliza MacLean, an owner of the farm and a former veterinarian, advises farmers across the state on the transition from tobacco to pork. Every bit of that care comes through in the flavor of the finished product, a stunning bargain at $3.25."

Farmers are also benefiting from this local food movement:

"Mr. Brinkley, [a] farmer, says that his family’s farm, and many others, might not have made it through the loss of the tobacco cash crop without the lucky coincidence of the rise in the local food movement. Now, chefs compete over his lady peas, pink-eyed peas and butternut squash — a relatively exotic vegetable here, he said, where the sweet potato was once the king of the winter table."

Read more here: http://www.nytimes.com/2010/04/21/dining/21carolina.html?8dpc

(image from visitsouth.com)

Ant Farms

Ant-fungus mutualism is one of the many interesting interactions in the animal kingdom. It is a highly evolved symbiosis observed in certain species where the ants cultivate or farm fungus for food -- fungiculture and/or fungivory, if you will. The ants grow, fertilize, clean, and weed patches or gardens of fungi in their underground tunnels and caverns. This mutualism is thought to have originated approximately 45-65 million years ago in the ancestor of fungus-growing ants (Formicidae, tribe Attini). In the course of evolution, a switch was made from the hunter-gatherer lifestyle to a farming strategy. This switch has evolved only twice in ants: (1) in the attine ants and (2) in some species of the solenopsidine genus Megalomyrmex. In this second case the ants either coexist as trophic parasites in the fungal gardens cultivated by attine ants or they take over the gardens from the attine ants. (Read more here) It is estimated that there are more than 200 species of New World ant fungiculturists.

A new study in The American Naturalist reports that these ants update the crops they grow over time. The authors compared the multigene phylogeny to the fossil phylogenies of attine ants as well as the phylogenies of associated fungal clades. Basically, they looked at the accumulations of mutations in short stretches of DNA to see when certain species or strains of ant and fungi emerged. The researchers discovered that the fungi were significantly younger than the ants. For example, leaf cutter ants (one of the best known farmers) diverged from their anty ancestors 12 million years ago, they are significantly younger than the corresponding ant genera. It was thought that the fungus that they cultivate would have to be older, evolutionarily speaking, so that the ants could aquire and domesticate it. However, the fungus these ants farm only arose only 2-3 million years ago. This time difference suggests that the ants are cultivating a new fungal strain, a strain which has been spread to other colonies throughout the ants' range.

The article:
Mikheyev Alexander S., Ulrich G. Mueller and Patrick Abbot (2010) Comparative Dating of Attine Ant and Lepiotaceous Cultivar Phylogenies Reveals Coevolutionary Synchrony and Discord. The American Naturalist: 175, E126–E133. (DOI: 10.1086/652472)

and http://news.sciencemag.org/sciencenow/2010/04/farming-ants-update-their-crops.html

Sushi Love

A recent study in the journal Nature suggests that genes from a marine microbe have been transferred to human gut bacteria. This is the first clear case of gut microbes taking genes from ingested bacteria, allowing them to exploit a new niche. These genes encode for algae-digesting enzymes which break down carbohydrates, carbohydrates that are found in the red algae of the genus Porphyra, known to sushi lovers as nori. What makes this story important? It the clear-cut nature of the transfer, a pretty rare event.

Get more information about the encoded enzymes and their actions here: http://www.nature.com/news/2010/100407/full/news.2010.169.html
The Nature article: http://www.nature.com/nature/journal/v464/n7290/full/nature08937.html (DOI: 10.1038/nature08937)

(image from weblogs.fox40.com)