Worldwide amphibian declines have reached crisis proportions. In many areas, habitat loss is the likely culprit but, in 1996, it was suggested that some unknown disease had spread through the populations. In 1998, the fungus Batrachochytrium dendrobatidis was identified from sick and dead frogs and, since then, several lines of laboratory based evidence have suggested that B. dendrobatidis is to blame for the dramatic frog declines. But with little information about how the disease impacts frogs in the wild, the causal role of this chytrid fungus remains unclear. In the open access journal PLoS Biology, Australian researchers Richard Retallick, Hamish McCallum and Rick Speare now "show unequivocally" that remaining populations of T. eungellensis, a rainforest frog listed as endangered, can persist in the wild with stable infections of this fungus.
To evaluate the effects of the fungus on frogs in their natural habitat, the authors focused on six species living in the high-elevation rainforest streams of Eungella National Park in Queensland, Australia, where frog losses were "particularly catastrophic". Two species vanished between 1985 and 1986: the Eungella Gastric-Brooding Frog (Rheobatrachus vitellinus), which is now thought extinct, and the Eungella Torrent Frog (Taudactylus eungellensis), which later reappeared in a few small populations. In the PLoS Biology study, Retallick et al. tested tissue samples taken from frogs between 1994 and 1998 - before the disease had been identified. The marked frogs were released back into the wild at the time the samples were collected. The authors found fungal infections in the samples of two species, including T. eungellensis. An analysis of tissue from recaptured frogs during the same period showed that the prevalence of infection did not vary from year to year, suggesting that the infection is now endemic. McCallum and colleagues also found no evidence that survival differed between infected and uninfected frogs, suggesting that this potentially devastating amphibian disease now coexists with the frogs, with little effect on their populations.
While these findings do not exonerate the fungus as the agent of mass declines, they can rule out the possibility that the fungus caused the decline, then vanished from the area, allowing frog populations to recover. Although its possible that B. dendrobatidis did not cause the initial T. eungellensis declines, surviving frog populations may have developed resistance to the pathogen, or less virulent strains of the fungus may have evolved. If it turns out that frog populations can develop resistance to the chytrid fungus, the researchers point out, then a conservation program of captive breeding and selecting for resistance could potentially thwart the extinction of these, and other, critically endangered frogs.
Paul Ocampo | EurekAlert!
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy