AJCs Virtual Frogroom

The kaiseri saga

noreply@blogger.com (AJC) — Sun, 08 Nov 2009 09:07:00 +0000

My group of Neurergus kaiseri are still continuing to lay regularly, but I'm having problems raising any offspring. For a start, the adults have turned into ravenous egg and larvae eaters, so unless I'm quick, nothing survives for long. This is quite different from my previous experience with this species, where I was able to raise the offspring to metamorphosis quite easily in the same large, semi-aquatic vivarium as the adults.

I can find some of the eggs, but finding and removing larvae from the large, heavily planted vivarium is next to impossible. Nevertheless, since I figured out the eggs were being eaten, for the last month I've been trying to raise larvae in another vivarium, but without much success. Today, I discovered the reason why. There is a large and thriving colony of Gammarus (scuds) in the vivarium. I don't know what species of Gammarus this is (there are lots), but they are pretty voracious predators on newly hatched larvae.

Consequently, I'm having to resort to trying to raise the larvae in a plastic tub. Normally, I don't have a great deal of success with this method - I tend to do better raising caudate larvae in large, heavily-planted aquaria. However, this is a reasonably large storage box (~15 litres), stuffed full of plants and has been established for a while, so hopefully this will work. I'll let you know.

Another amphibian extinction

noreply@blogger.com (AJC) — Thu, 05 Nov 2009 16:31:00 +0000

Kihansi spray toad goes extinct in the wild:

This year's IUCN Red List has updated its assessment of the Kihansi spray toad, moving the species from Critically Endangered to Extinct in the Wild. With that another amphibian species has been lost to a combination of habitat loss and the devastating amphibian disease, the chytrid fungus. The Kihansi spray toad Nectophrynoides asperginis, which still survives in a number of zoos in the United States, had lived on just two hectares along the Kihansi gorge in Tanzania. The toad was specially adapted to the spray region of the Kihansi waterfall, which kept its small environment at a constant temperature and humidity."

One third of all amphibian species in danger

noreply@blogger.com (AJC) — Tue, 03 Nov 2009 11:48:00 +0000

Telegraph.co.uk

Flying frog and mountain mouse among new species in danger of going extinct Telegraph.co.uk
Already the golden toad from Costa Rica has gone extinct and hundreds of brightly coloured treefrogs in the Amazon are endangered. ...
Lizards, rodent, frog added to endangered listThe Associated Press
In pictures: Threatened speciesBBC News
Red alert: scientists identify 17000 endangered speciesIndependent
Scientific American -People & the Planet -AFP
all 148 news articles »

Frog embryos 'smell' predators

noreply@blogger.com (AJC) — Fri, 30 Oct 2009 12:21:00 +0000

Frog embryos 'smell' predators

BBC News

BBC News
Frogs learn to recognise the smell of their enemies while they are still developing as embryos, say scientists.

Researchers in the US and Canada found that woodfrog embryos were able to learn the "level of threat" posed by their future predators - salamanders.

Embryos put into water containing the odour of a salamander and the odour of injured tadpoles learned that the predator's smell was a threat.

And the stronger the odour, the more dramatic the tadpoles' reaction.

more »

Dartfrogs for sale (UK only)

noreply@blogger.com (AJC) — Thu, 22 Oct 2009 08:00:00 +0000

I currently have the following frogs for sale (sorry, UK only):

Dendrobates leucomelas: 3-6 months old, currently ~25mm SVL.
Not sexable at this age. £25 each

Email: alan dot cann at gmail dot com

New vivaria

noreply@blogger.com (AJC) — Sun, 18 Oct 2009 09:44:00 +0000

After a bit of a delay, I got around to setting up the two new vivaria I bought a while ago. Not very exciting yet, but they'll look better when they've grown in:

One contains juvenile Dendrobates leucomelas, the other D. tinctorius Patricia, but I hope to put something more exciting in there eventually.

dendrobates national geographic

noreply@blogger.com (AJC) — Mon, 05 Oct 2009 14:24:00 +0000

Si, it's in Spanish, but some very nice biotope shots:

Waxmoth Larvae

noreply@blogger.com (AJC) — Wed, 30 Sep 2009 08:39:00 +0000

The greater waxmoth (Galleria mellonella) and the lesser waxmoth (Achroia grisella) can both be cultured in the same way.
What's the difference? Galleria reproduces explosively, taking a long time to get going, then producing a very large number of 3-4 cm long larvae. Achroia grows faster initially but more steadily, with larvae and adult moths present in the culture at most stages, producing steady supply of 2-3 cm long larvae - more useful for dendrobatid keepers:

Both types of waxmoth can be cultured on a medium consisting of approximately:

3 parts wheatbran
3 parts wheatgerm
3 parts ReadyBrek
1 part dried yeast
Enough honey and glycerin (=glycerol) to produce a dry, crumbly mixture (*not* sticky).

Add lots of crumpled up paper towels to the culture for pupation. Cultures need lots of ventilation or you get condensation and they go moldy. I use plastic food storage containers the lids of which have a section removed and replaced by metal gauze glued in place with silicone adhesive, or better, melted into the lid with a soldering iron. Whatever culture vessel you use, bear in mind that the larvae have an amazing ability to chew through almost anything that is not made of either glass or metal.

When first set up, the culture appears to stand still. The original moths, however, will have laid thousands of eggs, and the larvae which hatch from these are extremely tiny, remaining well hidden for a few weeks. Then, suddenly, they seem to appear from nowhere and chomp through the food at an alarming pace. At the same time they generate a tremendous amount of heat, and the base of the culture will be distinctly warm. Not only that, but water produced from respiration will condense on the inside of the lid and sides of the container, even if it is well ventilated. This can cause the medium to become rather too wet and soggy if there is insufficient ventilation.

To feed, just pick the larvae out of the medium and offer them to your animals.

Dominance

noreply@blogger.com (AJC) — Sat, 19 Sep 2009 14:03:00 +0000

In most species of Dendrobates, the males tend to get along, although they will compete with each other by calling. With females however, it's a different matter. Two female Dendrobates will rarely tolerate each other in the same territory - and bear in mind that in the wild, Dendrobates territories are several metres in diameter (and in height), and probably separated by visual barriers. In a vivarium, more than one female usually results in the death of the weaker of. this is usually caused either by the stronger female droning th weaker one by pinning them down in water, or eventually by a stress-related condition brought on by constant harassment. This great video by stemcellsareawesome shows juvenile Dendrobates auratus beginning to sort out dominance by wrestling. At this stage, the females need to be separated in different vivaria:

A surprise egg

noreply@blogger.com (AJC) — Sun, 06 Sep 2009 08:51:00 +0000

At last this year's Mesotriton alpestris apuanus larvae have metamorphosed. Not too many this year, but this is where the fun starts! At this stage, these rather small (~3cm) metamorphs are the best escape artists I know, capable of squeezing through the tiniest cracks and incredibly persistent. For a few weeks after metamorphosis, they are quite hydrophobic and have a pronounced tendency to climb, so the lid of their mostly aquatic vivarium is now sealed with tape all the way round! Fortunately, this stage passes after a few weeks, and with good feedings of springtails and Drosophila, they soon lose interest in climbing and become more aquatically-oriented again.

I thought that was going to be the major interest for the day, but to my surprise when I was cleaning the Neurergus kaiseri vivarium, I discovered a lone egg. In February I moved my group of 2007 sub-adult Neurergus kaiseri from a terrestrial setup into a semi-aquatic vivarium with my adult pair. Although they have not been temperature-cycled, it seems as though the move from a terrestrial to a semi-aquatic setup was the trigger for this, and it seems to be one of the younger females which is laying. This tends to support my theory that cycling between terrestrial and aquatic phases as happens in their natural habitat is important for this species, possibly more so than temperatures.

Although I have seen male courting behavior, I can't tell yet if the egg is fertile, so the wait over the next week or so is going to be interesting...

Fighting Back

noreply@blogger.com (AJC) — Wed, 02 Sep 2009 11:49:00 +0000

In southeast Wyoming's Mortenson Lake, there's a death match going on between the amphibian chytrid fungus and the Wyoming toad, one of the most endangered amphibians in the United States. Observers had expected the fungus to kill off the species, but, while many toads have died, the population is slowly growing again...

Chytrid and the Mountain Chicken

noreply@blogger.com (AJC) — Fri, 28 Aug 2009 07:57:00 +0000

The dodo blog (from the Durrell Wildlife Conservation Trust) reports on efforts to save the mountain chicken (Leptodactylus fallax) in Montserrat. Video:

I've never met God, but if I did, I'm pretty sure he'd sound like David Attenborough

noreply@blogger.com (AJC) — Sun, 02 Aug 2009 08:34:00 +0000

Lost a leg? No problem!

noreply@blogger.com (AJC) — Sat, 04 Jul 2009 10:07:00 +0000

Cells keep a memory of their tissue origin during axolotl limb regeneration. Nature 460, 60-65 (2 July 2009)
During limb regeneration adult tissue is converted into a zone of undifferentiated progenitors called the blastema that reforms the diverse tissues of the limb. Previous experiments have led to wide acceptance that limb tissues dedifferentiate to form pluripotent cells. Here we have reexamined this question using an integrated GFP transgene to track the major limb tissues during limb regeneration in the salamander Ambystoma mexicanum (the axolotl). Surprisingly, we find that each tissue produces progenitor cells with restricted potential. Therefore, the blastema is a heterogeneous collection of restricted progenitor cells. On the basis of these findings, we further demonstrate that positional identity is a cell-type-specific property of blastema cells, in which cartilage-derived blastema cells harbour positional identity but Schwann-derived cells do not. Our results show that the complex phenomenon of limb regeneration can be achieved without complete dedifferentiation to a pluripotent state, a conclusion with important implications for regenerative medicine.

Invasive hybrid tiger salamanders impact native amphibians

noreply@blogger.com (AJC) — Thu, 02 Jul 2009 08:12:00 +0000

Although the ecological consequences of species invasions are well studied, the ecological impacts of genetic introgression through hybridization are less understood. This is particularly true of the impacts of hybridization on “third party” community members not genetically involved in hybridization. We also know little about how direct interactions between hybrid and parental individuals influence fitness. Here, we examined the ecological effects of hybridization between the native, threatened California Tiger Salamander (Ambystoma californiense) and the introduced Barred Tiger Salamander (Ambystoma tigrinum mavortium). Native x introduced hybrids are widespread in California, where they are top predators in seasonal ponds. We examined the impacts of early generation hybrids (first two generations of parental crosses) and contemporary hybrids derived from ponds where hybrids have been under selection in the wild for 20 generations. We found that most classes of hybrid tiger salamander larvae dramatically reduced survival of two native community members, the Pacific Chorus Frog (Pseudacris regilla) and the California Newt (Taricha torosa). We also found that native A. californiense larvae were negatively impacted by the presence of hybrid larvae: Native survival and size at metamorphosis were reduced and time to metamorphosis was extended. We also observed a large influence of Mendelian dominance on size, metamorphic timing and predation rate of hybrid tiger salamanders. These results suggest that both genetic and ecological factors are likely to influence the dynamics of admixture, and that tiger salamander hybridization might constitute a threat to additional pond-breeding species of concern in the region.

Invasive hybrid tiger salamander genotypes impact native amphibians. PNAS USA June 29, 2009

The mystery of the legless frogs

noreply@blogger.com (AJC) — Thu, 25 Jun 2009 14:41:00 +0000

Scientists think they have resolved one of the most controversial environmental issues of the past decade: the curious case of the missing frogs legs. Around the world, frogs are found with missing or misshaped limbs, a striking deformity that many researchers believe is caused by chemical pollution. However, tests on frogs and toads have revealed a more natural, benign cause. The deformed frogs are actually victims of the predatory habits of dragonfly nymphs, which eat the legs of tadpoles. In the late 1980s and early 1990s, researchers started getting reports of numerous wild frogs or toads being found with extra legs or arms, or with limbs that were partly formed or missing completely. The cause of these deformities soon became a hotly contested issue. Some researchers believed they might be caused naturally, by predators or parasites. Others thought that was highly unlikely, fearing that chemical pollution, or UV-B radiation caused by the thinning of the ozone layer, was triggering the deformations.

Meanwhile in Ecuador...

noreply@blogger.com (AJC) — Tue, 23 Jun 2009 13:32:00 +0000

More on chytrid

noreply@blogger.com (AJC) — Fri, 05 Jun 2009 08:31:00 +0000

Using itraconazole to clear Batrachochytrium dendrobatidis infection, and subsequent depigmentation of Alytes muletensis tadpoles.
Dis Aquat Organ. 2009 Feb 25;83(3):257-60
Batrachochytrium dendrobatidis (Bd) is a global threat to amphibian biodiversity. Current calls for conservation through captive breeding require that efficient and reliable antifungal treatments be developed for target species. Here we confirm that the antifungal itraconazole is an effective treatment for infection in larval Alytes muletensis (Mallorcan midwife toad). Exceptionally low doses applied as few as 7 times were effective at clearing infection from tadpoles for up to 28 days after treatment. However, we cannot recommend itraconazole as a treatment for this species as depigmentation of tadpoles was observed. Further research is required to determine the putative hepatotoxicity of this treatment.

Lack of Evidence for the Drought-linked Chytridiomycosis Hypothesis.
J Wildl Dis. 2009 Apr;45(2):537-41
A significant amount of recent research has focused on the potentially synergistic roles of climate change and disease in causing amphibian declines and extinctions. Herein I discuss the drought-linked chytridiomycosis hypothesis (DLCH), which states that prolonged or intensified dry seasons trigger or exacerbate epidemics of chytridiomycosis, a potentially lethal skin disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis. I demonstrate that the DLCH runs contrary to our knowledge of B. dendrobatidis physiology, biogeography, and host-parasite ecology and conclude that abnormally dry weather should actually favor amphibians by decreasing the prevalence, severity, and spread of chytridiomycosis.

Wild Dendrobate auratus in Costa Rica

noreply@blogger.com (AJC) — Tue, 02 Jun 2009 07:16:00 +0000

Breakfast for the Brazils

noreply@blogger.com (AJC) — Sat, 30 May 2009 10:23:00 +0000

I don't normally bother putting flies in a dish, but occasionally if a lot of crud comes out of the culture and mixes with the files I do in order to avoid too much getting in the viv. Still, it gave them a chance to be sociable :-)

Sobering discovery for Europe’s amphibians

noreply@blogger.com (AJC) — Wed, 20 May 2009 18:01:00 +0000

A new report commissioned by the European Commission and carried out by IUCN highlights alarming declines for a range of frogs, toads, newts, snakes and lizards. The study shows that of Europe’s 85 species of amphibian, 23% now feature on the IUCN’s Red List of Threatened Species:

Overall, nearly a quarter of amphibians are considered threatened in Europe. A further 17% of amphibians are considered Near Threatened. By comparison, 19% of European reptiles, 15% of European mammals and 13% of European birds are threatened. No other groups have yet been comprehensively assessed at the European level. More than half of amphibians (59%) have declining populations. A further 36% are stable, and only 2% are increasing.
The overwhelming majority of threatened and Near Threatened amphibian species are endemic to both Europe and the EU, highlighting the responsibility that European countries have to protect the entire global populations of these species. All species considered threatened (Critically Endangered, Endangered, or Vulnerable) at the European level are endemic to Europe and are found nowhere else in the world.
Amphibian species richness is greatest at intermediate latitudes (France, Germany, Czech Republic) as well as in the south and on islands. Habitat loss, fragmentation and degradation are the most significant threats to amphibians in Europe. Other major threats include pollution (including global climate change caused by greenhouse gas emissions) and invasive alien species.

Tylototriton kweichowensis

noreply@blogger.com (AJC) — Sun, 17 May 2009 14:22:00 +0000

Busy Saturday

noreply@blogger.com (AJC) — Sat, 16 May 2009 11:16:00 +0000

Most weekends, Saturday is my main day in the frogroom, and in addition to the regular maintenance schedule, today seemed to be particularly busy:

Two egg clutches from Dendrobates tinctorius Patricia and Dendrobates leucomelas
Lots of new Mesotriton alpestris apanus larvae
Set up some new rearing boxes for froglets:

But the funniest thing was moving an adult Dendrobates azureus female into a viv with a younger pair who haven't got the hang of the breeding thing yet. I wish I'd taken a video of the ensuing chaos. I had been slight;ly worried about the possibility that the females might fight, but instead, as soon as she clapped eyes on the male, she was after him, chasing him round the viv, stroking and generally behaving in a lustful fashion. He looked terrified!

I think I might be needing those new frog boxes soon :-)

Pacific Tree Frog - Pseudacris regilla

noreply@blogger.com (AJC) — Wed, 13 May 2009 08:00:00 +0000

Pacific Tree Frog via kwout

Vivarium for sale

noreply@blogger.com (AJC) — Sun, 10 May 2009 09:09:00 +0000

90 x 30 x 30cm (30 long x 12 wide x 12 inches), top opening vivarium.
Ventilated escape-proof lid, suitable for amphibians, reptiles, insects, rodents, etc.
£15, buyer collects from Leicester.

SOLD!