Spectacular Autumn migrants: ringed salamanders

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A gravid female ringed salamander (Ambystoma annulatum) en route to her breeding pond.

It’s that time of year again. The wind starts to get a certain chill, pumpkin lattes are being sold at every coffee shop, and the leaves are beginning to change color. This is also the time of year that an Ozark native salamander, the ringed salamander (Ambystoma annulatum) migrates to breed. Like the spotted salamanders (Ambystoma maculatum) and jefferson salamanders (Ambystoma jeffersonianum) mentioned in an earlier post, ringed salamanders are members of the family Ambystomatidae (the lunged salamanders) and they breed in ephemeral ponds. However, ringed salamanders breed in the fall, so their migrations take place mostly on rainy nights during the month of October. Like other Ambystomatid salamanders, they spend most of their time hidden and are difficult to see when they are not migrating.

A male ringed salamander (Ambystoma annulatum) with complete rings almost all the way down his body.

A male ringed salamander (Ambystoma annulatum) with complete rings almost all the way down his body.

Photos do not do ringed salamanders justice, as they are rather large and impressive salamanders, longer in body than spotted salamanders but still not nearly as large as their relatives, the tiger salamanders. The yellow rings on their body give them an almost exotic look and on top of that, they have adorable little faces with pop-out eyes. Yet, like many other amphibians, they are highly vulnerable to road mortalities during their migration. One gravid female hit by a passing vehicle represents the loss of an entire clutch of eggs as well as her future reproductive potential. So please, if you live in ringed salamander territory, watch the roads carefully for salamanders this month and help across any that you find!

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My new favorite North American salamander, the ringed salamander (Ambystoma annulatum)

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Captive conditions influence amphibian skin microbes

The Panamanian golden frog (Atelopus zeteki) currently only exists in captivity. Photo by Matthew Becker.

The Panamanian golden frog (Atelopus zeteki) currently only exists in captivity, meaning that its microbial skin community has probably changed considerably. Photo by Matthew Becker.

As amphibians decline around the globe, more and more species are being pulled into captivity to initiate breeding programs for population insurance purposes. However, there is some speculation as to whether this is actually a viable method of species conservation, since captive frogs are eventually going to become different from their wild counterparts. In fact, their microbial communities most likely dramatically change within a matter of weeks of them being taken into captivity. A new study by in the open access journal PLoS ONE reveals that microbial diversity not only declines precipitously in captivity, but diet can have a significant effect on the microbial community. The authors conducted a simple experiment where captive bred red-eyed tree frogs (Agalychnis callidryas) were fed either crickets gut-loaded with a carotenoid-rich diet, or crickets that were not gut-loaded with carotenoids. The results showed that captive red-eyed tree frogs fed carotenoids had more diverse skin microbiota, indicating that carotenoids could influence the survival of skin bacteria.

Antwis et al. fed captive  red-eyed tree frogs (Agalychnis callidryas) diets rich in carotenoids and carotenoid-free diets to test the effect of diet on skin microbe communities.

Antwis et al. fed captive red-eyed tree frogs (Agalychnis callidryas) diets rich in carotenoids and carotenoid-free diets to test the effect of diet on skin microbe communities.

Amphibian guts are thought to serve as a reservoir of microbial diversity for the amphibian skin (see Wiggins et al. 2011 for an example from redback salamanders). Therefore, not only environment but also diet in captivity could be resulting in the dramatic declines in microbial biodiversity seen on amphibian skin. This has a lot of conservation implications since species being maintained in captivity may lose disease resistance due to having a less diverse skin community. Further studies are needed to tease apart the diversity = disease resistance hypothesis regarding amphibian skin microbes. If it is the case that all of the captive frogs are becoming less resistant to the amphibian chytrid fungus, perhaps there are husbandry changes that can be made to boost the skin microbe communities of the frogs, such as including probiotics into the substrate used for housing the frogs, or utilizing more natural tank conditions rather than just sanitary paper towels and plastic dishes.

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Amphiumas, mudpuppies and sirens, oh my!

Sirens (Siren sp.) retain larval gills throughout their life and also lack hind limbs.

Sirens (Siren sp.) retain larval gills throughout their life and also lack hind limbs.

Among the ever-growing list of those amphibian species found to be infected with chytrid are a few fully aquatic species of salamanders. In the southeastern U.S. there are several species of aquatic paedomorphic salamanders that retain larval characteristics, such as gills, throughout their life. This is also known as neoteny. Although hellbenders (Cryptobranchus alleghaniensis) are fully aquatic, they are not paedomorphic since they undergo metamorphosis. Axolotls (Ambystoma mexicanum), common in captivity but virtually extinct in the wild, are a pretty well-known example of neoteny or paedomorphosis. As in the popular song, though, a few rare aberrant axolotls can actually metamorphose into a salamander (this is not because they drank “salamander goo” but more likely due to a genetic mutation).

Two-toed amphiumas (Amphiuma means) may serve as reservoirs for Bd in aquatic environments.

Two-toed amphiumas (Amphiuma means) may serve as reservoirs for Bd in aquatic environments. Photo by J.D. Willson.

Several species of  southeastern paedomorphic salamanders in the U.S. were swabbed for chytrid fungus  in a 2012 study. The authors found a relatively high rate of infection, with an overall prevalence of 0.34 (so about 34 out of 100 individuals swabbed were found to be infected with Bd on average). Among the different kinds of salamander that they swabbed, amphiuma (Amphiuma sp.; eel-like salamanders with tiny legs) and sirens (Siren sp.) seemed to have the highest average Bd prevalence values relative to dwarf sirens (Pseudobranchus) and mudpuppies (Necturus sp.; large paedomorphic salamanders similar to axolotls). No declines in these aquatic species were recorded and the authors suggested that amphiumas, sirens and mudpuppies could serve as reservoirs of Bd since they are in water bodies where chytrid may be present all the time.

Frog: 11, Fungus: 17

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Projects on microbes and chytrid at JMIH 2014

For the past few days I have been at the 2014 Joint Meeting of Ichthyologists and Herpetologists, which met in Chattanooga, TN this year. To my slight surprise, there were a large number of talks and posters on chytrid and on microbial communities of amphibian skin. Here is some information on just a couple of those.

1. Grace from the Karen Lips lab at University of Maryland presented evidence that Atelopus zeteki was a “super-shedder” of Bd that could potentially amplify the number of chytrid zoospores in the environment. This was due to the high concentrations of Bd found on their skin following infection, and, when soaked in water, high concentrations of zoospores were detected from the water. The Pacific chorus frog (Pseudacris regilla) is also thought to be a carrier of the chytrid fungus, but it does not die as quickly as the Panamanian golden frog does in the presence of the fungus so it might function more in allowing the fungus to persist rather than amplifying it.

2. Bd was detected in the Virgin Islands for the first time on Eleutherodactylus sp. by Dr. Renata Platenberg from the University of the Virgin Islands.

3. Skin microbe communities from 8 different species of plethodontid salamanders were examined by Amanda Allison and Ben Fitzpatrick. They found no significant differences between the different species of salamanders, but the bacterial communities were different from the environment, suggesting that a generalized probiotic could be used to protect several species of plethodontids at once.

It was clear from the number of posters and talks on bacteria at the meeting that microbial communities of reptiles and amphibians are becoming more widely studied. This is unsurprising, given the recent discoveries of the role of symbiotic bacteria in the human gut. I am optimistic that further breakthroughs in the study of symbiotic microbial communities will be forthcoming in the next few years.

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Immune resistance and avoidance of deadly fungus by frogs

A new study published this year in the journal Nature provides evidence that vaccinations against Bd may be an effective measure of protection. The researchers found that frogs exposed to the chytrid fungus would avoid it during a second exposure, or gain acquired immunity through the production of white blood cells. Since even dead Bd strains set off an acquired immune response in the frogs, it might be possible to inoculate some species of frogs with dead chytrid strains to equip them against the living pathogen, much like how our vaccinations work. More research needs to be done to explore this study’s findings, but it seems very promising.

Frog: 11, Fungus: 16

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Fabulous frog videos

Do you like David Attenborough? Do you like frogs? If your answer to one or more of these questions is a resounding “Yes!” then you need to watch this video. PBS Nature’s “Fabulous Frogs” is full of stunning footage of some of the most spectacular frogs and toads, including the Panamanian Golden Frog in the wild. The only thing that I felt was lacking was a little bit more on conservation and the importance of frogs to society. I had also hoped that there was going to be something on the Kihansi spray toad since that is one of my favorite species of conservation concern (they are just too cute!). Nevertheless, seeing David Attenborough interact with monkey tree frogs and African bullfrogs was far too priceless to pass up watching.

Anyway, if you enjoyed that video and are hankering for more frog videos, SavetheFrogs.com has an entire page devoted to them. Hope you enjoy!

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Spectacular salamanders of the U.S. and other things

The peaks of otter salamander (Plethodon hubrichti) is endemic to a small range in the Blue Ridge Mountains.

The peaks of otter salamander (Plethodon hubrichti) is endemic to a small area in the Blue Ridge Mountains

This month I have added several species of salamanders to my life list. Many of these salamanders are endemic to relatively small mountain areas and are pretty special in coloration. Although locally common, I had not yet seen the Peaks of Otter salamander (Plethodon hubrichti) until earlier this month we finally ventured over to an area we knew was likely to contain them. The Peaks of Otter salamander looks similar to a redback salamander, only with a back flecked with gold-green. While on the same trail I had seen the Peaks of Otter salamander on, I happened to come across another fabulous salamander species that I had not seen yet, although this one was not an endemic – the spring salamander (Gyrinophilus porphyriticus). These relatively large and robust salamanders can often be found in cool water springs and streams.

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Spring salamander (Gyrinophilus porphyriticus)

Continuing my search for new species, I ventured to Grandfather Mountain in North Carolina in search of the Yonahlossee Salamander (Plethodon yonahlossee), another species with a relatively small range. Although I saw this species in North Carolina, they are also believed to occur in southwest Virginia. The Yonahlossee salamander is another large terrestrial salamander species with a beautiful reddish-brown stripe running along the middle of the back.

The colorful Yonahlossee salamander (Plethodon yonahlossee)

The colorful Yonahlossee salamander (Plethodon yonahlossee)

The Southeastern United States is a hotspot for fabulous salamander species such as these. One major reason for this is all of the mountain ranges that isolated salamander populations so that they became new species, such as the Peaks of Otter salamander. If you’re looking for lungless salamanders in particular, this is the country to be in.

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A cope’s gray treefrog (Hyla chrysoscelis) calling from the rim of a highly eutrophic pool of water.

But of course, this blog would not be “Frog vs Fungus” without frogs. While in North Carolina, I also tracked down a group of Cope’s gray treefrogs (Hyla chrysoscelis) that I heard calling. To my surprise, they were calling from what appeared to be a sewage pond. I am not sure if any tadpoles would survive in that disgusting pool of water, but I was amazed once again at the apparent resilience and adaptation of amphibians to changes in their environment.

 

Lastly, this is a little late in coming, but here is a link to a radio interview with Reid Harris & Candace Hansen on the Amphibian Survival Alliance. The radio show is called “Herpin’ Time”. Enjoy!

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Frog vs Fungus: Keeping score

So I just decided to do something that I probably should have started a long time ago. To go along with the theme of this blog’s title (“Frog vs Fungus”) I have decided to keep score of the outcomes of the articles and information that I review. If the study showed that amphibians were able to defend themselves from chytrid or if it killed Bd, then I scored it for “Frog”. If the fungus was found on something new or killed something, then it was a score for “Fungus”. There are a number of posts that either were not directly related to the chytrid problem or where the interactions were so complex that it was not clear whether the frog or the fungus won. In those cases, I did not include the score at the bottom of the post. As it stand right now, our current score is Frog: 10, Fungus: 16. This does not bode well for frogs, but hopefully there will be some new probiotics studies this year that might turn the tide. Stay tuned to find out!

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Save the Frogs Day: Knitted frogs for sale

 

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Happy Save the Frogs Day! For a limited time only I have four handknit miniature frog plushies available for sale. Three are made with rainbow yarn and one with orange. Two of the rainbow frogs have their hind legs sewn so that they are curled, but that could easily be changed if desired. They are $10 each or $32 for all four together, plus shipping if needed. All proceeds from the sale will go towards Save the Frogs, a nonprofit organization dedicated to amphibian conservation. If you are interested, please email me at mswart175@gmail.com with “Save the Frogs knitted frogs” in the subject line.

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Earth Day Amphibian Highlight: Hellbenders!

The eastern hellbender (Cryptobranchus alleghaniensis) has a face some think only a mother could love. Photo by Brian Gratwicke.

The eastern hellbender (Cryptobranchus alleghaniensis) has a face some think only a mother could love. Photo by Brian Gratwicke.

Happy Earth Day, everyone! To celebrate this occasion, I want to kick it off with some information on the largest salamander in the United States, the eastern hellbender (Cryptobranchus alleghaniensis alleghaniensis). Hellbenders (a.k.a. snot otters, lasagnasides, etc.) are believed to be from a more primitive and ancient lineage of salamanders that is found only here in the U.S. and in Asia. There are two kinds of hellbenders here in the States: our Eastern hellbender and the Ozark hellbender (Cryptobranchus alleghaniensis bishopi). In Asia, there are two species: the Japanese giant salamander (Andrias japonicus) and the Chinese giant salamander (Andrias davidianus). All are highly threatened by habitat loss and pollution of waterways.

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In Virginia, hellbenders are found more in the Southwestern part of the state and prefer habitats with lots of rocks. If you want to see them, you will quickly find that those who know where they can be found are protective of that knowledge, and for good reason. The eastern hellbender is listed by the Virginia Wildlife Action Plan as Tier II: Very High Conservation Need, and they are thought to be found in only a few waterways.

There are several characteristics that make hellbenders completely unique among other salamanders in Virginia. First, they are entirely aquatic, with the adults using cutaneous respiration to absorb dissolved oxygen from the water (this is why their sides are so wrinkly – to create more surface area for oxygen absorption). Second, the father hellbender guards the eggs in a den, usually formed under a large rock or in a burrow. Thirdly, they are extremely slimy! This can help them escape from predators, as they are very hard to hold on to and can exude nasty-tasting slime.

Baby hellbenders basically look like adorable miniatures of the adults.

Baby hellbenders basically look like adorable miniatures of the adults.

Eastern hellbenders are one of Virginia’s most unique and fascinating amphibians, but unfortunately they are in danger from a myriad of threats. Diseases such as the amphibian chytrid fungus (Batrachochytrium dendrobatidis) and ranavirus may be negatively affecting some populations. In some areas, people may kill hellbenders due to fear, misconceptions or prejudices against them (imagine if you did not know about hellbenders and were fishing when you pulled in a huge salamander – you would probably be frightened, too). These large salamanders, like many other amphibians, are also sensitive to pollutants in their environment (see this awesome animated video). One of the greatest problems, however, is siltation and development of waterways. Silt is the number one pollutant in Virginia and originates from runoff and erosion. It can cover up or fill in the rock crevices that hellbenders use as dens or homes. There are several initiatives such as Help the Hellbender that seek to educate others and to provide funding for research and conservation of these amphibians. I hope that we will be able to conserve hellbenders for future generations to appreciate and be awed by.

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