Hey, Excuse Me… Is This Guy Boring You?

pone.0100366 Featured Image

Imagine that you’re sitting on a Cretan beach. The sun’s shining and waves are lapping on shore, when suddenly a set of jaws dripping copious amounts of saliva appear above you like some sort of CGI horror masterpiece, wanting to bore a hole in you big enough to crawl through. While this is hopefully not something you need to worry about, it is in fact a concern for the Albinaria land snails that inhabit the Greek islands. Who are the boorish culprits? No other than small beetle larvae of the genus Drilus (shown above), a land snail predator.

In a study recently published in PLOS ONE, researchers aimed to gain a better understanding of the predator-prey interactions between Drilus beetle larvae and Albinaria land snails. They predicted that land snail species with a greater number of ribs on their shell were better protected from invasion; if correct, this would mean the type of predation may affect shell evolution in this species.

The authors surveyed over 1,000 groups of land snail shell samples from a museum and mapped, by region, the frequency of land snail deaths by beetle larvae. Then, using DNA sequencing, they found that while some species of beetle larvae only prey on Albinaria, others take a more generalist approach and feed on a variety of land snail species.

The authors also found that beetle larvae can kill without ever actually having to bore a hole in the snail’s shell. In fact, of the ~170 Albinaria shells the authors collected that showed evidence of a beetle larvae attack, 60 shells had no holes. The researchers suggest that despite the potential challenges of entering through the main opening, such as encountering the clausilium—essentially a front door that the snail can shut (as drawn above)—boring into the shell is still a more rigorous task.

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The scientists’ also directly observed the beetle larvae preying on the land snails, which reinforced that it was not necessary to bore a hole for entry; however, they found that the beetle larvae almost always exited by boring. While there does not seem to be an obvious explanation for why this variation in entry/exit method exists, each choice has its own advantages and disadvantages. The observation period further revealed that the beetle larvae took its time leaving the shell, often living inside it for 22-32 days after each kill before molting and moving on.

Though we still do not have a clear understanding of how these interactions directly impact shell evolution, the authors hope this research provides a basis for future work to build upon. Regardless, I think it’s safe to say that this ‘boring’ research yielded some rather informing results.

Citation: Baalbergen E, Helwerda R, Schelfhorst R, Castillo Cajas RF, van Moorsel CHM, et al. (2014) Predator-Prey Interactions between Shell-Boring Beetle Larvae and Rock-Dwelling Land Snails. PLoS ONE 9(6): e100366. doi:10.1371/journal.pone.0100366

Images: All images are from the article.

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Worms in the Big Apple: Identifying Patterns of Toxocariasis Infection in New York City

For thousands of Americans, roundworm infection may pose a serious threat to their health. Toxocariasis, an illness caused by a parasitic roundworm, can potentially cause chronic health problems, including ocular infections, diminished lung function, and poor cognitive development. It is estimated to be one of the most prevalent neglected infections of poverty (NIP) in the United States, a group of “under the radar” infections that cause major problems for those living in poverty.

Public health officials know that toxocariasis is highly prevalent in urban areas and inner city neighborhoods, but beyond that, this disease isn’t tracked or treated like other illnesses where extensive background research is more accessible. The authors of a paper published in PLOS ONE in June of this year attempted to take a step closer to addressing this issue by looking at how data like ethnicity, education level, or neighborhood size in New York City can provide clues to the likelihood of toxocariasis occurrence.

Figure 1

The researchers in this study used the only source of population-based and location-specific information about toxocariasis that was available: a 1988-1994 National Health and Nutrition Examination Survey (NHANES) that contains a collection of data used to estimate the prevalence of this infection around the United States. By applying these statistics to highly detailed census data from urban areas of New York City, the authors could estimate the probability of toxocariasis in different demographics or neighborhoods. The results of this are shown in the map above.

Figure 2

As this second map indicates (click to enlarge), several different ethnicities in inner cities are at a higher risk for this infection. For instance, African Americans in New York City show a 64% greater risk of infection, and immigrants had a 92% greater chance of infection in comparison to those born in the US. Not only that, New Yorkers’ education levels also correlated with infection: the risk of toxocariasis was about 6% among US-born Latino women with a university education, and up to 57% among immigrant men with less than a high school education. These populations appear to be at particularly high risk for infection, and might be among the first groups surveyed in targeted sampling.

The results of this study are particularly telling for the US’ largest city, which holds almost 8.4 million people in all of its diverse neighborhoods. Wandering the streets of New York at any moment, you might hear one of 800 spoken languages. The dense populations of this city are key to understanding where and why these neglected infections of poverty can develop. More specifically, the colorful areas of these maps can be used to guide testing in inner city neighborhoods.

A few limitations of the study might be that the nationwide (NHANES) survey was conducted 15 years earlier, and it captured far fewer details than the New York City census data. Still, the vivid depictions of these statistics can provide us with much-needed maps for further research and potential surveillance. With more surveillance of this illness, we can gather more data, track, and study this disease. Once we have improved sampling methods, we can better address the public health needs of our urban areas.

Citation: Walsh MG, Haseeb MA (2014) Small-Area Estimation of the Probability of Toxocariasis in New York City Based on Sociodemographic Neighborhood Composition. PLoS ONE 9(6): e99303. doi:10.1371/journal.pone.0099303

Images: All images are from the article.

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Catch the Katydid if You Can


Katydid pic 1

It’s too fast to catch, spears smaller insects with spiny legs, and sings a song that mirrors the syllables of its name, “Ka-ty-did, Ka-ty-didn’t.­ Its music is so catchy, it has even been used as the chorus of popular songs.

Listroscelidinae are a group of insectivorous katydid hunters from South America whose fast and aggressive behavior makes them difficult to capture, let alone identify. According to the authors of a recent PLOS ONE study, these Neotropical katydids have been understudied, partly because we haven’t been able to get our hands on them. However, the authors of this study managed to collect more than 100 specimens from one of the world’s most threatened ecosystems, the Brazilian Atlantic Forest.

They compared these new specimens to existing samples from museums by collecting DNA samples and creating simplified illustrations to document the differences between the physical characteristics in each species. In addition to measuring the phalluses and abdomens, they traced the placement of stridulatory files on their wings, shown in the image below, which katydids rub together to make noise. The different placement of these bands allowed the researchers to distinguish between related species.

After examining the physical characteristics and DNA samples, researchers were able to identify and name eight new species of Neotropical katydids, which have been very difficult to classify and have been re-categorized several times in the last century.

The most distinctive feature of these Neotropical katydids is their spiked legs, which they use to skewer and ensnare insect prey. A close relative of the Listroscelidinae, the Red-eyed Devil, has been documented performing the katydid hunt.

Katydids blogpost

The authors caution that these species may be seriously endangered as they are found only in highly-preserved sections of this threatened forest. Identifying these species has helped reshape how researchers think about them, but there is still much research to be done on this group of Neotropical katydids, as long as researchers can catch up with them!

Citation: Fialho VS, Chamorro-Rengifo J, Lopes-Andrade C, Yotoko KSC (2014) Systematics of Spiny Predatory Katydids (Tettigoniidae: Listroscelidinae) from the Brazilian Atlantic Forest Based on Morphology and Molecular Data. PLoS ONE 9(8): e103758. doi:10.1371/journal.pone.0103758

Images: All images are from the article.

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Detection by Dung: Don’t Eat the Brown Snow


Researchers in Antarctica on a mission to locate penguin colonies found two groups of seabirds, thanks to a little help from satellites, helicopters, and the detection of more “primitive” evidence: penguin poop.

Our favorite tuxedo-clad Emperor penguin is native to Antarctica, but harsh winter conditions and the remoteness of some colonies can make it difficult for biologists to gain a comprehensive population assessment of this “hiding” bird. The first breeding penguin colony was discovered in Antarctica in 1902, and in 1999 thousands of birds were sighted near the Mertz glacier in Antarctica, but for the last century, suspected colonies of Emperor Penguins in the area had yet to be confirmed.

In this recently published PLOS ONE study, the authors used both survey- and satellite-based methods to locate the presence of Emperor penguin colonies on the Mertz glacier, where a previous sighting of thousands of birds had occurred 15 years ago, but a drastic habitat change—the glacier’s “tongue” broke off in February 2010—may have disrupted.


Aerial surveys captured two new potential breeding grounds for colonies, the Eastern and Western (~7,400 breeding pairs total).  Satellite images from a thousand feet in the sky helped the authors detect the Eastern colony by the presence of fecal marks—or in bird specialist speak, “guano”—in the snow.

The red arrow in the image above points out the lovely brown streak of guano strewn across the ice shelf, which indicates the Eastern colony’s previous breeding ground. The authors used this streak as an indication that the Eastern colony was likely close by. Below the guano-streaked, snow-packed shelf, the presence of the Eastern colony was confirmed by researchers trekking across treacherous terrain to visually confirm the presence of the birds.

Unlike the Eastern colony, who mobilized to a fresh home post-breeding, the Western colony seemingly didn’t mind remaining in their breeding muck. This colony was discovered not by satellite but by chance during helicopter flight operations in Antarctica. Although the authors had difficulties finding the Western colony by aerial footage, as pictured in the below image, these social gatherers appeared to differ from the Eastern colony in that they inhabited a large flat surface, and the colony appeared to be much larger.


In the cases of both colonies, aerial surveys appeared to be very effective for locating them. So, until humans evolve warmer winter coats, scientists conducting surveys by foot are still limited by frigid conditions and isolated locations in future South Pole endeavors. To obtain a more accurate picture of total penguin counts, the authors suggest taking multiple aerial images during the breeding season and conducting several-year surveys to confirm numbers in suspected Antarctic penguin colonies. But for now, the game of Hide and Go Poop will continue.

Citation: Ancel A, Cristofari R, Fretwell PT, Trathan PN, Wienecke B, et al. (2014) Emperors in Hiding: When Ice-Breakers and Satellites Complement Each Other in Antarctic Exploration. PLoS ONE 9(6): e100404. doi:10.1371/journal.pone.0100404

Image 1: Emperor Penguins by Lin Padgham

Image 2-3: Figures 1 and 2 from article

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Article-Level Metrics Highlight: Top 10 of the Summer

summerHaving just published our 100,000th article, the staff at PLOS ONE realizes that easily finding research papers among our wide selection is very important to our diverse community. This is one reason we’ve now joined forces with the PLOS article-level metrics (ALMs) team to regularly identify and present a selection of our recently published papers that demonstrate high ALM activity*. This post will be the first in a series that highlights new content for our readers.

From genetics to paleontology and microbiology to ecology, all the papers featured here have drawn the attention of the general public and scientific community over the past four months. This list is just the tip of the iceberg and if you haven’t already perused these papers, we encourage you to explore the work here and join the rich conversations already ongoing surrounding them.

Without further ado, this month’s top papers include the following:

1. Investigating “knockin” and “knockdown” in a human cell line

Using CRISPR/Cas9, a biological gene editing system that has allowed rapid and efficient modification of an organism’s DNA—as well as captured the imagination of biomedical researchers in the last two years—the authors of “CRISPR/Cas9 Allows Efficient and Complete Knock-In of a Destabilization Domain-Tagged Essential Protein in a Human Cell Line, Allowing Rapid Knockdown of Protein Function” were able to add a destabilizing element to “knockdown” an essential gene ( TCOF1) in a human cell line, effectively impairing cell growth and controlling protein levels. This strategy will hopefully allow the authors to investigate this gene further, as it is critical for cell growth and viability and has been associated with Treacher Collins–Franceschetti syndrome.

Published 4/17/2014, Image from the article

2. The shapes of 2.1 billion year-old macroscopic marine biota

The authors of “The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity” analyzed the shapes and structures of fossilized material from the Paleoproterozoic Era—when the Earth’s surface and atmospheric environment was still in flux—found in the Francevillian black shale rocks in southeastern Gabon in Central Africa. The results suggest a biota fossilized during the formation of sedimentary rocks, likely following the rise and fall of atmospheric oxygen. These 400 biota may represent the oldest known macroscopic organisms.

Published 6/25/2014, Image from the article

3. Musical training may benefit young brains

The authors of “Behavioral and Neural Correlates of Executive Functioning in Musicians and Non-Musicians” put working adult musicians, adults with no musical training, and kids with a couple years of musical training through a series of tasks to measure various cognitive capabilities. They found that the adults and children with musical training showed enhanced performance in working memory and processing speed compared to those without training.

Published 6/17/2014, Image from the article

4. Cheers for the “bugs” in Lambic beers’ (yeast and bacteria)

Traditional Lambic sour beers ferment for one to three years before bottling using wild yeast and bacteria from the air of the Senne river valley in Belgium. To dive into the microbial diversity in fermenting Lambic sour beer in a brewery in Belgium, the authors of “The Microbial Diversity of Traditional Spontaneously Fermented Lambic Beer” analyzed over 2000 bacterial and yeast isolates. They found a wide variety of bacterial species and only minor variation between batches. The authors also observed a pattern in the way the “bugs” changed during the fermentation process, which started with a mostly Enterobacteriaceae, replaced by Pediococcus damnosus and Saccharomyces spp. in the second month, and finally replaced at 6 months by Dekkera bruxellensis. Understanding the progression of “bugs” might allow breweries from around the world to replicate this region-specific fermentation process.

Published 4/18/2014, Image: Brakspear Oxford Gold Organic Beer by Christer Edvartsen

5. Latent virus reactivation in patients with sepsis

Reactivation of latent viruses may occur with prolonged sepsis. The authors of “Reactivation of Multiple Viruses in Patients with Sepsis” analyzed blood samples from critically-ill septic, critically-ill non-septic, and healthy patients to see if certain latent viruses—herpesviruses, polyomaviruses, and the anellovirus TTV—reactivated in these patients. The results suggested latent virus reactivation may be common with prolonged sepsis, consistent with development of an immunosuppressive state.

Published 6/11/2014, Image: Model of a Virus by Tom Thai

6. Prehistoric crocodiles may have dined on each other

The authors of “An Additional Baurusuchid from the Cretaceous of Brazil with Evidence of Interspecific Predation among Crocodyliformes” have discovered the fossils of a new crocodyliformes (crocodilians), Aplestosuchus sordidus, from the Late Cretaceous in Brazil.  Not only did the researchers find a new species, but they also discovered fossilized remnants of another crocodylian inside its stomach, suggesting that Aplestosuchus sordidus likely feasted on other crocodyliforms.

Published 5/8/2014, Image from the article

7. Microbes hitching a ride on the skin of a humpback whale

Humpback whales live in oceans around the world and the authors of “Humpback Whale Populations Share a Core Skin Bacterial Community: Towards a Health Index for Marine Mammals?” genetically sequenced over 500,000 bacteria collected from humpback whale skin from different geographical areas, as well as in various health conditions to explore the role these microbes play in their health. They found that in general, two bacterial species, Tenacibaculum and Psychrobacter, were hitching a ride on most healthy whales, but the overall composition of the bacterial populations differed depending on their various geographical locations, as well as on whether individual whales were stressed or deceased. These results indicate that scientists may be able to monitor these widespread whales’ health using microbes in the future.

Published 3/26/2014, Image from the article

8. Up close with 3D insects

Scientists working to develop a cost-effective method to create natural-color 3D models of insects in “Capturing Natural-Colour 3D Models of Insects for Species Discovery and Diagnostics” have used “off-the-shelf” equipment to image and model the insects in 3D. The 3D models are compact in size (~ 10 MB each); have excellent resolution; and can be embedded into documents and web pages, as well as mobile devices. The authors report that the system is portable, safe, and relatively affordable; complements existing imaging techniques; and opens up opportunities to use images of these delicate specimens for research, education, and art.

Published 4/23/2014, Image from the article

9. Mass extinction may not have resulted in slow recovery of prehistoric predators

Organism recovery after the end-Permian mass extinction is thought to have been slow, lasting up to eight million years or more. The authors of “Early Triassic Marine Biotic Recovery: The Predators’ Perspective” surveyed the global distribution and size of Early Triassic and Anisian marine predatory vertebrates—fishes, amphibians and reptiles—to take a closer look at organism recovery after the mass extinction event. Scientists observed no significant predator size increase from the Early Triassic to the Anisian, as would be expected with slow or stepwise recovery. These results likely indicate that from the Early Triassic onward, marine ecosystems were comprised multiple trophic levels.

Published 3/19/2014, Image from the article

10. Let’s study lions, tigers, and bears (and more?)

Scientists work hard to understand the role carnivores play in ecosystems, but all carnivorous species may not receive the same amount of attention. To investigate further the patterns in carnivore research, the authors of “Correlates of Research Effort in Carnivores: Body Size, Range Size and Diet Matter” combined bibliometric information they obtained from ~16,500 published papers on the Order Carnivora, a well-known group of nearly 300 species. The researchers found that scientists tend to study carnivores with large bodies and large geographic ranges, like bears and walruses, moreso than species with greater adaptability and broader diets.

Thank you for taking a moment to enjoy these PLOS ONE papers from the past four months. We’re looking forward to next list and meanwhile, you may explore our ALMs report to make your own lists.

* This list will be selected each month from a report of papers generated based on the following ALMs ratio: PDF downloads/HTML ratios.  Only papers published within the last four calendar months were eligible for inclusion. (This list was pulled from March 15, 2014- July 15, 2014)

First image: Llegó el verano – Summer is here by Guillermo Viciano

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I Smell Green, You Smell Blue

Color Palate

In elementary school, we all learn about our five senses: taste, smell, touch, sight, and sound. Together, they continuously provide us with massive amounts of sensory input. One way we make sense of all this is by forming associations: between sights and smells, feelings and tastes, and so on. For instance, we may associate the sound of waves to the smell of the ocean, the feeling of sand between our toes, or a salty taste. But to what extent do sensory associations change based on where we are from, and to what extent are they universal? It turns out that two people from opposite sides of the globe may draw very different connections from the same stimulus. That’s according to the authors of new research published in PLOS ONE, who investigated how people from different parts of the world associate colors with smells.

The researchers divided study participants into six populations based on geographic categories: Dutch, Netherlands-residing Chinese, German, Malay, Malaysian-Chinese, and US residents. Participants smelled a series of scents—14 total, including smells like “meat,” “soap,” and “burnt”—and were subsequently asked to choose from a palate of colors which one they most closely associated with the smell.

Odor-color associations chosen by the different groups

After the experiments were performed, the researchers compared the smell-color associations of individuals within each groups, and then compared the results between groups. While people from the same geographic group tended to make similar smell-color associations, color choices differed significantly between the cultural groups.  Some smell-color associations were generalizable across groups.  For instance, participants who smelled a “fruity” odor largely picked a pink or red color, and people chose oranges and browns for the “musty” smells.  The most similar groups to each other were the US and Germany, and the Germany and Malay samples.  Overall, the Malay group’s color choices were the most different from all the others. The authors had also predicted that the geographically-close test groups would lead to similar smell-color associations, but that didn’t appear to be borne out by the data.

So, what may be happening when someone smells a scent, and then chooses a corresponding color? The authors offer several possible explanations of what could be at work:

  • There could be an underlying neural basis for the association of reds and pinks with fruity smells that lead people to associate the two. In other words, the associations are inherent and that’s just how our bodies and our brains work.
  • There could also be a statistical correspondence, which means that a particular color and smell often accompany one another. Example: “I see red and I smell fruit… perhaps the two are related.” Over time, these patterns may start to leave their mark on our brains.
  • Sometimes people make strong associations with colors and words (perhaps “sky” and blue), called semantically mediated correspondences. Language and how it is used can influence these associations, so this experiment was designed to use as few words as possible to minimize language-based associations.

In this particular study, the authors suggest that the variation between the different cultural groups may be evidence that color-smell associations are not inherent or universal, but are informed by other factors that could include culture, language, and experience. More work remains to better understand all the factors that influence these connections, but for now, it seems that the color of a smell may depend on where you’re from.

Related links:

The Color “Fruit”: Object Memories Defined by Color

From Understanding to Appreciating Music Cross-Culturally

Which Colors Do You Smell?

Reference: Levitan CA, Ren J, Woods AT, Boesveldt S, Chan JS, et al. (2014) Cross-Cultural Color-Odor Associations. PLoS ONE 9(7): e101651. doi:10.1371/journal.pone.0101651

Images: The images come from Courtney Rhodes via Flickr and Figure 2 of the published paper

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Sharing is Caring: Varied Diets in Dinosaurs Promoted Coexistence


Everyone loves a good dinosaur discovery. Though they’re few and far between, sometimes we get lucky, finding feather imprints, mohawks, or birthing sites that reinvigorate public interest and provide bursts of insight about how they ruled the Earth before our arrival.

Dinosaurs must have been doing something right because they coexisted for millions of years, much longer than we humans have even been on the planet. In an article recently published in PLOS ONE, University of Calgary researchers studied markings on dinosaur teeth to determine how a diverse group of megaherbivores—plant-eating species whose adults weighed in at over 1,000kg—was able to coexist in Canada for at least 1.5 million years. The authors’ findings suggest that these dinosaurs managed to last so long by eating things that the others didn’t, thereby reducing competition for food and promoting a more harmonious (if dinosaur life could be considered so) coexistence.

The authors of this study started by taking a look at general tooth shape and any markings visible to the naked eye before moving onto examine the microscopic markings on teeth. The presence of certain small shapes or marks on teeth may indicate what type of food an individual ate during its lifetime, and can be analyzed using a technique called microwear analysis. As you might guess, foods with different textures or hardness leave different markings on our teeth. For instance, pits in the teeth suggest consumption of hard foods like nuts, while scratches are linked to the ingestion of tough leaves or meat. A combination of both reflects a varied diet.

The researchers analyzed a group of 76 fossils from 16 species in three ancestral groups, focusing on teeth still connected to skulls to provide more accurate species identification. These three groups lived together during the Cretaceous period in the Dinosaur Park Formation of Alberta, Canada, which at that point was on an island continent called Laramidia.


Ankylosaur Teeth

Ankylosauria, whose teeth are seen above, were a group of armored, stocky dinosaurs. One subgroup, the ankylosaurids, had small, cusp-like teeth (marked A) good for eating fruits and softer plant tissues, while another, the nodosaurids (marked B), had blade-like teeth useful for tougher and more fibrous plant tissues. Microwear analysis showed no significant difference between these two subgroups, meaning that, despite differences in general tooth shape, results indicate that their diets did not differ significantly. The evidence of both pits and scratches on their teeth suggests that both ate a variety of fruits and softer foliage.


Hadrosaurid Teeth

Hadrosauridae—identifiable by their duckbill-shaped face—had similar microwear to the Ankylosauria, suggesting that they also had a generalized diet, though their broad teeth, likely used for crushing food, may have made it easier for them to consume all parts of targeted plants, including stems and seeds, than the cusp or blade-like teeth found in the Ankylosauria.


Ceratopsid Teeth

Ceratopsidae, a family of thick-skulled, horned dinosaurs, including the well-known Triceratops, had teeth that functioned as shears, suggesting that they consumed particularly tough plants. Microwear analysis supports this idea, indicating more scratches than pits, and showing that these dinosaurs may have subsisted on mainly rough foliage, like twigs and leaves.

The evidence provided by microwear analysis, incorporated with other known facts about these species, such as height, skull shape, and jaw mechanics, helps paint a broader picture of the dinosaur food scene in Laramidia, and supports previous research suggesting that the varied diets allowed these large species to coexist for 1.5+ million years. Maybe we can take some cues from them to make sure we are at least as successful. Fingers crossed no meteors come along to ruin our chances.

Citation: Mallon JC, Anderson JS (2014) The Functional and Palaeoecological Implications of Tooth Morphology and Wear for the Megaherbivorous Dinosaurs from the Dinosaur Park Formation (Upper Campanian) of Alberta, Canada. PLoS ONE 9(6): e98605. doi:10.1371/journal.pone.0098605

Image 1: Triceratops prorsus skull by Zachi Evenor

Images 2-4: Figures 1, 9, and 6 from article

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The 2014 Ecological Impacts of Climate Change Collection

Ecology ColectionPost authored by Collection Curator Ben Bond-Lamberty

The impacts of climate change on global ecology, in its many forms and fields, were well represented by PLOS publications in 2013-2014. The articles chosen for the Collection were published by PLOS ONE and PLOS Biology and encompass several broad areas: experimental manipulations and observations, modeling, paleoecology, long-term studies, and support for mitigation and adaptation.

Experimental manipulation and observation are fundamental to understanding climate change impacts. For example, Anadon-Rosell et al. used a six-year soil warming experiment to examine how three dwarf shrubs may respond to high-altitude climate change, while Tair and Schiel use laboratory manipulations to study primary production and respiration in algae. Both studies point out that communities may be more severely affected than what might be expected based on the response of individual species. Such species interactions feature in a fascinating study by Pringle et al., who survey a Mesoamerican precipitation gradient and report that trees invest more in ant defenders when water is scarce; they conclude that rare but extreme herbivory events interact with water limitation to reinforce this mutualism. The interactive effects between species are studied in a theoretical setting by Northfield and Ives, who use simple models to show that coevolution can result in feedback loops that either dampen or amplify climate change effects. Modeling is also used by Riordan and Rundel in a very different arena, to examine how land use and climate change may interact in California sage scrub ecosystems across the 21st century.

The ecological past holds many clues for the present and future. For example, paleobotanical evidence has shown rapid post-glacial movements of many tree species, faster than current observed migration rates. Feurdean et al. address this uncertainty using a macrofossil database, literature estimates, and process models to highlight the importance of microrefugia. Migration rates are partly a function of demographic processes, a subject examined by a 2014 PLOS ONE study on growth-mortality relationships in piñon pines of the U.S. southwest. Moving to the Mediterranean, Kaniewski et al. also mine the past for information, using radiocarbon, tree cores, and pollen records to reconstruct millenial changes and vulnerabilities of coastal ecosystems in northern Israel.

Long-term observational datasets are relatively rare and extremely valuable. A 26-year study of Magellanic penguins near Argentina found that climate change–in particular, increased rain–has lowered reproductive success in the world’s largest breeding colony of these birds. The authors conclude that similar patterns may undermine the resilience of other species in the region. The complexity of species’ responses to climate changes is emphasized by Ryan et al., who updated a 42-year-old survey of Costa Rican forest frogs. Population declines were linked with changes in temperature, rainfall, and leaf litter depth, but without any consistent pattern across the sites and species surveyed.

Møller et al. use decadal data on European birds and their parasites to examine how both hosts and parasite populations can change with climate shifts. (We humans are of course hosts as well, as Thomassen et al. emphasize in examining the predicted range shifts of human monkeypox in response to central African climate change.) Striking similar notes, Zografou et al. report on changes in butterfly communities between 1998 and 2012 in Dadia National Park, Greece, which were found to correlate with longer-term environmental change, with different patterns at high and low elevations. Butterflies and elevation effects are also the subject of Roth et al., who report significant community shifts in vascular plants, butterflies, and birds over eight years in Switzerland.

Given that a great deal of climate change is inevitable in the coming century, it is important to understand how we can mitigate and adapt to the inevitable impacts. Writing in PLOS Biology, Mora et al. provide an assessment of changes in future ocean biogeochemical variables, and the broader implications of these changes for marine biota and people. A conceptually similar study in PLOS ONE looks at climate change impacts on terrestrial vertebrate hotspots, emphasizing the threat this poses for conservation of European biodiversity. Amorim et al. examine how monitoring networks can be designed to detect potential range shifts, taking into account species’ occurrence, conservation status, and unpredictable volunteer commitment. Finally, Rout et al. ask how we decide to move species threated by climate change, applying a qualitative decision framework to the case study of tuatara, a New Zealand reptile.

As I wrote a year ago, the broad range of these papers emphasize both the multi-faceted impacts of climate change on natural and human systems, as well as the breadth and depth of research on these subjects being published in PLOS journals.

BBLDr. Bond-Lamberty is a Research Scientist at the Joint Global Change Research Institute, a partnership of the Pacific Northwest National Laboratory (PNNL) and the University of Maryland, College Park. His research focuses on carbon cycling in terrestrial ecosystems, particularly boreal and other northern forests, and their response to natural and human-initiated disturbances. He has extensive experience modeling biogeochemical cycling in these systems, as well as in manipulative field and lab experiments. He also acts as a Section Editor for PLOS ONE.

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“Low T” and Prescription Testosterone: Public Viewing of the Science Does Matter

testosterone_grayOn January 29th 2014, researchers from UCLA, NCI, and Consolidated Research, Inc. published an observational study in PLOS ONE detailing increased cardiovascular risks associated with men taking testosterone therapy. Only three days later, on January 31st, this study in combination with another, published in JAMA in November 2013 with similar findings, triggered a Food and Drug Administration (FDA) Drug Safety Communication and evaluation that is currently ongoing. Since then, lawsuits against testosterone drug makers have been filed in both the US and Canada, and the FDA has set up a joint advisory committee who will meet this fall to evaluate potential health risks associated with testosterone therapies to determine whether any regulatory measures are required.

Why all the commotion around one or two scientific articles? The authors of the PLOS ONE study report that men aged 65 years and older who filled a testosterone prescription had double the risk of heart attack within three months. The study is based on a sample of 55,000 men from a dataset of enrollees in a health market database during the years 2006-2010. For younger men with pre-existing heart disease, the increased risk was two- to three-fold higher within the same period.

For matters relating to public health, this study is both relevant and controversial due to the skyrocketing of testosterone prescriptions to men, an industry now valued at $2 billion USD. Unfortunately, testosterone is often prescribed without a blood test for the medical diagnosis that warrants its use (hypogonadism), as it is also claimed to have other health benefits, including improved sex drive, mood, energy levels, and anti-aging effects.

Testosterone molecule

Testosterone molecule

While it’s clear that this PLOS ONE article impacted the actions of regulatory agencies and issues pertaining to public health, we wondered whether this influence was reflected in the paper’s article-level metrics (ALMs). Or, as Roli Roberts asked in a recent PLOS Biologue post, “how do you know when you’ve published a great paper?” Or even a good paper?

As it turns out, this paper did have an interesting, atypical trajectory post-publication. Rather than gaining traction first in the media, riding a flurry of social media activity, and then eventually attracting the attention of health regulators, immediate action was taken by the FDA within days of publication. Concurrently, the article received an explosion of media coverage within a week post-publication, including news pieces in the New York Times: Well Blog, NPR: Health News, and The Wall Street Journal MarketWatch, among others, and was continuing to receive coverage in the BBC News and NPR as late as April 2014. All of this coverage was recorded by our media tracking tool, which can be found under “Related Content” here.

Is the influence of this article captured in its ALMs? If we glance at individual measures, the article had ~ 21,000 views in the first month of publication, and currently has well over 36,000 HTML page views, 17% of which have resulted in PDF downloads. If we compare this view number to that of all other PLOS ONE articles published in the same timeframe, we see that this article is ranked 12th most-viewed. Additionally, a PDF download percentage of 17% is roughly average for a PLOS ONE article, where a higher percentage may indicate increased scholarly usage relative to other, more mainstream types of usage. On social media, this article was shared well over 100 times, which is substantial but less than occurred for other articles published since, with a few papers currently at well over 1000 shares.

However, if we examine citations and post-publication commentary seven months since publication, the study has already accumulated 20 citations, more than any other article published in this timeframe. In addition to accumulating citations, the article has prompted researchers to call for additional, more definitive studies: an article published in The Lancet Diabetes and Endocrinology cited the PLOS ONE and JAMA articles and declared an urgent need for large clinical trials of testosterone. Last but not least, the article has stimulated significant post-publication commentary from readers who have analyzed and critiqued the methodology and characteristics of the cohort, spurring further discussion and research,   and effectively moving post-publication peer review in a forward direction.

Therefore, the value of this article may not lie strictly in its views, shares, citations, or even saves, or any combination or calculation thereof, but instead in its open access visibility to the public, healthcare providers, federal agencies, and media outlets. Anyone, anywhere in the world with Internet access can read this article and its surrounding discussion and then decide for themselves how to respond and react, and that alone is worth more than any level of metrics combined.


Finkle WD, Greenland S, Ridgeway GK, Adams JL, Frasco MA, et al. (2014) Increased Risk of Non-Fatal Myocardial Infarction Following Testosterone Therapy Prescription in Men. PLoS ONE 9(1): e85805. doi:10.1371/journal.pone.0085805

Vigen R, O’Donnell CI, Barón AE, et al. Association of Testosterone Therapy With Mortality, Myocardial Infarction, and Stroke in Men With Low Testosterone Levels. JAMA. 2013;310(17):1829-1836. doi:10.1001/jama.2013.280386

Piszczek J, Mamdani M, Antoniou T, Juurlink DN, Gomes T (2014) The Impact of Drug Reimbursement Policy on Rates of Testosterone Replacement Therapy among Older Men. PLoS ONE 9(7): e98003. doi:10.1371/journal.pone.0098003


Rx image from Ano Lobb on Flickr.

Testosterone image from Benjah-bmm27.

Category: Aggregators, Article-Level Metrics, Images, Internet/Blogging, Media, Open Access, Peer review, Social Media | Tagged , , , , , , , , , , , , , , , , | 2 Comments

Does the Fox Say, “I Love Living in the City?”

flickr fox Steve K CCBY


Most wild animals move away from areas heavily populated by humans, noisy cars, and sparse natural habitat. Some, however, thrive in the city, learning to hustle to provide for themselves and their families just like the rest of us. Urban wildlife like raccoons and turkeys roam my neighborhood in the San Francisco bay area, stealing food from the compost heap and perching on top of administrative buildings. Other parts of the world see monkeys, moose, or even foxes in their urban centers. Recently, researchers teamed up with citizen scientists to investigate the distribution of urban red foxes in Great Britain. They published the results of their survey in an article in PLOS ONE, “Changes in the Distribution of Red Foxes (Vulpes vulpes) in Urban Areas in Great Britain: Findings and Limitations of a Media-Driven Nationwide Survey.”

Keeping track of animal populations in cities is important for wildlife management and public health, but it is by no means an easy task. Cities are crazy quilts of fences, private residential property, public areas, and commercial property, all with varying degrees of accessibility that can make research on animal distribution a challenge. For these reasons, the authors of this study recruited volunteers to help with the fox survey. Utilizing the eyes and attention of citizen scientists allowed the scientists to evaluate a wide urban area without stomping through everyone’s gardens.

The authors recruited participants using television programs about foxes, with each program including information about how to participate in the fox survey. Participants were asked to submit records and locations of fox sightings with photos via a website. Citizen science makes research like this possible, but it does have drawbacks, including that the  data quality relies on the accurate reporting of many untrained individuals who are much more likely to report positive data points (such as the presence of a fox in their area) rather than negative data points (an absence of foxes), which can skew results.

To improve data reliability, researchers double-checked for errors in location and date. They focused on determining how widespread the foxes were, which is easier to gauge with this method, rather than how densely populated the foxes are, which would be more difficult with potentially skewed data.



The results of this study indicated that, compared to their distribution in the 1980s, foxes have further spread out over Britain, with sightings reported in 91% of 65 cities that were previously thought to have few or no foxes. It is unclear why they have expanded their colonization of British urban areas, but according to the authors they do seem to prefer private backyards to public green spaces. More fox sightings were reported in cities with higher human population densities, as can be seen in the graphic above, but the researchers noted that this result could easily be due to increased reporting and not necessarily related to a higher number of foxes. All in all, more research is needed to determine why the distribution of red foxes in Britain is changing, and whether the fox population is increasing or just spreading out. In the meantime, the authors have made their data available for anyone to have a look.


Scott DM, Berg MJ, Tolhurst BA, Chauvenet ALM, Smith GC, et al. (2014) Changes in the Distribution of Red Foxes (Vulpes vulpes) in Urban Areas in Great Britain: Findings and Limitations of a Media-Driven Nationwide Survey. PLoS ONE 9(6): e99059. doi:10.1371/journal.pone.0099059

Flickr image “Oops, I woke up the Fox asleep by my backdoor” by Steve K

Fox sightings map figure is from the article

Category: Aggregators, Images, Worth A Thousand Words | Tagged , , , , , | Leave a comment