Fatal chytrid fungus found in caecilians

This is really bad news. New research shows that chytrid fungus now infects all the major groups of amphibians and means that scientists now need to consider it as a potential threat to caecilians in the wild.

Because most species of caecilians live buried in the soil, they are rarely studied and very little is known about most of them. As a result, more than two thirds of caecilian species are 'Data Deficient' on the IUCN Red List because there is too little information to know if they are threatened or not. The last thing we need is massive species loss due to chytrid.

Keeping Sticky

How do frogs' toe pads stay sticky to stop them falling? Why don't they get clogged with dirt and stop sticking? Tree frogs' sticky toe pads remain clean after thousands of uses while sticky tape is useless after one. It turns out that the simple act of walking is sufficient to clean their toe pads.

First scientists tested how well contaminated and uncontaminated White's tree frogs clung to a glass plate as they rotated it from horizontal, through vertical to upside down. Because the frogs tended to want to jump off when they began to feel insecure, they gently encouraged the frogs to hold tight by shielding them with their hands and caught them when the plate became too steep and the frog's hold failed. Monitoring the plate's angle, the team found that the frogs with uncontaminated feet only began to slip as the plate tipped over (106 deg) and finally lost their grip at 142 deg. However, when they dusted the frog's feet with microscopic glass beads, the animals began slipping soon after the glass plate began to tilt. They had lost adhesion, so how could they recover?

Holding a tree frog on a computer-controlled stage and carefully applying a single layer of glass beads to one of its toe pads, they carefully pressed the contaminated toe onto a glass coverslip and then pulled it free. Measuring the adhesion force as they pulled the frog away, they found that it had fallen to zero: the frog was completely incapable of clinging on to the smooth surface with its contaminated feet. Simply dabbing the toe onto a surface was not sufficient to clean it. However, when they simulated real tree frog footsteps, by gently dragging the toe pad sideways after contact with the coverslip, the situation was completely different. Over the course of eight simulated footsteps the toe pad gradually recovered adhesion, slowly at first, returning to normal by the final contact.

So the keys to the tree frog's self-cleaning success are the sliding motion – which shears particles away from the toe pad and increases the contact area with the surface – and the sticky mucous secretions – which help flush away contaminants.


Self-cleaning in tree frog toe pads; a mechanism for recovering from contamination without the need for grooming. (2012) The Journal of experimental biology, 215(22), 3965-3972
Tree frogs use adhesive toe pads for climbing on a variety of surfaces. They rely on wet adhesion, which is aided by the secretion of mucus. In nature, the pads will undoubtedly get contaminated regularly through usage, but appear to maintain their stickiness over time. Here, we show in two experiments that the toe pads of White's tree frogs (Litoria caerulea) quickly recover from contamination through a self-cleaning mechanism. We compared adhesive forces prior to and after contamination of (1) the whole animal on a rotatable platform and (2) individual toe pads in restrained frogs mimicking individual steps using a motorised stage. In both cases, the adhesive forces recovered after a few steps but this took significantly longer in single toe pad experiments from restrained frogs, showing that use of the pads increases recovery. We propose that both shear movements and a 'flushing' effect of the secreted mucus play an important role in shedding particles/contaminants.

• Treefrog Glue
• Sticky Gecko Feet: The Role of Temperature and Humidity

Complex history of chytrid

Scientists have just published a complicated scientific paper on the devastating amphibian pathogen Batrachochytrium dendrobatidis (Bd - chytrid). The full version is below, but here's the summary:

They sequenced the genome from 29 isolates of Bd from around the world and found a lot more genetic variation than previously reported. So what? This means that the worldwide chytrid "pandemic" is more complicated than previously thought, and one size does not fit all outbreaks.

The major disease-linked amphibian population declines predate the late 20th century emergence of this pathogen in amphibians. Is Bd was simply an unrecognized member of amphibian communities that suddenly turned lethal and is it a new pathogen? This new data Bd shows that Bd has been in some amphibian populations for a very long time. In others it is a recent introduction. Proteases are confirmed as important in Bd infection of amphibian skin and in causing the disease.

The history of the chytrid pandemic is complex and a long way away from the idea that a "new" disease suddenly wiped out many of the world's amphibians.



Complex history of the amphibian-killing chytrid fungus revealed with genome resequencing data. PNAS USA 06 May 2013, doi: 10.1073/pnas.1300130110
Understanding the evolutionary history of microbial pathogens is critical for mitigating the impacts of emerging infectious diseases on economically and ecologically important host species. We used a genome resequencing approach to resolve the evolutionary history of an important microbial pathogen, the chytrid Batrachochytrium dendrobatidis (Bd), which has been implicated in amphibian declines worldwide. We sequenced the genomes of 29 isolates of Bd from around the world, with an emphasis on North, Central, and South America because of the devastating effect that Bd has had on amphibian populations in the New World. We found a substantial amount of evolutionary complexity in Bd with deep phylogenetic diversity that predates observed global amphibian declines. By investigating the entire genome, we found that even the most recently evolved Bd clade (termed the global panzootic lineage) contained more genetic variation than previously reported. We also found dramatic differences among isolates and among genomic regions in chromosomal copy number and patterns of heterozygosity, suggesting complex and heterogeneous genome dynamics. Finally, we report evidence for selection acting on the Bd genome, supporting the hypothesis that protease genes are important in evolutionary transitions in this group. Bd is considered an emerging pathogen because of its recent effects on amphibians, but our data indicate that it has a complex evolutionary history that predates recent disease outbreaks. Therefore, it is important to consider the contemporary effects of Bd in a broader evolutionary context and identify specific mechanisms that may have led to shifts in virulence in this system.

Dendrobates azureus

Frogroom Weekend - 14th April

Magnificent brood frog (Pseudophryne covacevichae). Endangered on the IUCN Red List.


The Big Newt Count - Monday 22 April, Fens Pool, Dudley. Join ecologists for an interesting evening of newt counting on the Fens Pools near Dudley.




Saviors or villains: controversy erupts as New Zealand plans to drop poison over Critically Endangered frog habitat.



Who’s afraid of the big fat frog? A man with a phobia of frogs has won $1.6million in damages after run-off water from a neighbouring property turned his home into an amphibian-friendly wetland.



Nasikabatrachus sahyadrensis - the Purple Frog, or the Pignose Frog.



Not all frogs come from tadpoles. All tadpoles grow into frogs, but not all frogs start out as tadpoles, reveals a new study on 720 species of frogs.



The Panamanian golden frog (Atelopus zeteki) is a small species of “true toad” native to the mountainous rainforests of Panama — although now thought to be extinct in the wild, and currently surviving only in captivity.



Dead frogs, drowning mice, sick dogs – it’s not a jolly spring for some creatures. Frogs … the pit canaries of the planet. If they go, we’ve probably all had it.

To Understand the Springtail, you must Become the Springtail

In 2005 Steve Hopkin, God of All Things Springtail, published this great review about my favourite springtail species (whaddya mean, you don't have a favourite springtail species?), Folsomia candida.

Folsomia candida (Collembola): A “Standard” Soil Arthropod. (2005) Annual Review of Entomology 50: 201-222

Among the great snippets of information it contains are the following gems:


Folsomia candida is parthenogenetic and is easy to maintain in the laboratory on a diet of granulated dry yeast.


F. candida has been used as a “standard” test organism for more than 40 years for estimating the effects of pesticides and environmental pollutants on soil arthropods.


F. candida is considered a tramp species (54). Because it has been carried all over the world in plant pots and soil its original biogeographical locations are difficult to ascertain.


Populations of F. candida consist exclusively of parthenogenetic females.


At 20°C they take between 21 and 24 days to reach the sixth, or adult, instar when they are sexually mature. At lower temperatures, the time span for each developmental stage is extended. For example, the average lifespan of a female at 15°C is 240 days, whereas at 24°C it is only 111 days.


About 30 to 50 eggs are laid in each batch, which take 7 to 10 days to hatch.


The optimal temperature for hatching success is 21°C. Eggs maintained above 28°C fail to hatch.


At 15, 21, and 27°C, the average number of eggs laid by a female during her lifetime is around 1100, 900, and only 100, respectively.


Eggs are often laid in communal heaps, in which females add to previously laid batches.


An adult female may go through 45 molts in her lifetime with short reproductive instars (duration 1.5 days) alternating with longer nonreproductive instars (duration 8.5 days).


All life stages of F. candida are well adapted to dry soil conditions. The species possesses physiological adaptations to desiccation and absorbs water vapor and remains active below 98.9% relative humidity (the permanent wilting point of plants).


Oxygen uptake is via the cuticle - F. candida does not possess tracheae.


The gut passage time of F. candida at 20°C is approximately 35 min.


F. candida feeds on fungal hyphae and exhibits strong preferences for particular species


The fungus on which F. candida feeds influences its growth and fecundity. Laboratory experiments with F. candida held in different microcosms, with only one species of fungus available in each, have shown that some taxa of fungi are more nutritious than others.


F. candida shows a mild preference to settle on soils of pH 5.6, at which females achieve their highest level of reproduction compared with more acidic or alkaline conditions.

Bumper Box of Plants

(Sorry, UK Only)

Starting a new viv? You need: Bumper Box of Plants (box not included)
Large well-rooted cuttings of:

Pellionia daveauna
Scindapsus aureus (Pothos)
Scindapsus pictus
Selaginella plana
Syngonium rayii
Tradescantia zebrina

Suited to a damp amphibian vivarium. Will thrive in moderate lighting. If you'd like more info, Google the names for pictures, and in some cases searching for the names on YouTube will work.
£15 (+ £5 P&P if needed, or collect from Leicester).

Daddy takes baby for a walk

New species of tiny frog is world’s smallest vertebrate

Researchers have found two new frog species in New Guinea, one of which is the new smallest known vertebrate on Earth. The new smallest vertebrate species is called Paedophryne amauensis, named after Amau Village in Papua New Guinea, where it was found. The adult body size for these frogs ranges from just 7.0 to 8.0 millimeters. The previous smallest vertebrate was a fish, called Paedocypris progenetica, with an adult size of 7.9 to 10.3 millimeters.


Rittmeyer EN, Allison A, Gruundler MC, Thompson DK, Austin CC (2012) Ecological Guild Evolution and the Discovery of the World’s Smallest Vertebrate. PLoS ONE 7(1): e29797. doi:10.1371/journal.pone.0029797
Living vertebrates vary drastically in body size, yet few taxa reach the extremely minute size of some frogs and teleost fish. Here we describe two new species of diminutive terrestrial frogs from the megadiverse hotspot island of New Guinea, one of which represents the smallest known vertebrate species, attaining an average body size of only 7.7 mm. Both new species are members of the recently described genus Paedophryne, the four species of which are all among the ten smallest known frog species, making Paedophryne the most diminutive genus of anurans. This discovery highlights intriguing ecological similarities among the numerous independent origins of diminutive anurans, suggesting that minute frogs are not mere oddities, but represent a previously unrecognized ecological guild.