Algemeen

Across host–parasite systems, there is evidence that pesticide exposure increases parasite loads and mortality following infection. However, whether these effects are driven by reductions in host resistance to infection or slower rates of parasite clearance is often unclear. Using controlled laboratory experiments, we examined the ability of larval northern leopard frogs (Lithobates pipiens) and American toads (Anaxyrus americanus) to resist and clear trematode (Echinoparyphium sp.) infections following exposure to the insecticide carbaryl.

A deadly fungal disease that’s infecting snakes in the eastern and midwestern United States doesn’t appear to discriminate by species, size or habitat, researchers report online December 20 in Science Advances. The infection, caused by the fungal pathogen Ophidiomyces ophiodiicola, can cover snakes’ bodies with lesions that make it hard for the reptiles to do normal snake things like slither and eat. Many eventually die from the infection. Fungal spores hang around in the soil and can spread to snakes that pick the particles up.

Nach den Amphibien jetzt die Reptilien: Jetzt haben Frank Burbrink vom American Museum of Natural History in New York und seine Kollegen eine weitere Pilzseuche entdeckt – und eine weitere gefährdete Tiergruppe: die Schlangen. Im Osten der USA sind bereits 23 Schlangenarten befallen, darunter drei Arten, die in Europa vorkommen. Das Bedrohliche daran: Der Erregerpilz scheint weder auf bestimmte Schlangengruppen noch auf spezielle Lebensräume oder Lebensweisen spezialisiert zu sein.

Die Deutsche Gesellschaft für Herpetologie und Terrarienkunde (DGHT) hat den Grasfrosch (Rana temporaria) zum Lurch des Jahres 2018 ernannt. Die Arbeitsgemeinschaft Fledermaus- und Amphibienschutz (AGFA) Seligenstadt und Mainhausen hat sich deshalb für nächstes Jahr die Kartierung, Zustandsbewertung, Dokumentation und eine mit der Naturschutzbehörde und dem Forst abgestimmte Pflege der Gewässer im Waldgebiet zum Ziel gesetzt.

Amphibian chytridiomycosis, caused by infection with the Batrachochytrium dendrobatidis fungus, is the most devastating vertebrate disease on record. The fungus infects more than 600 species of amphibian and has been implicated as the primary cause of decline in more than 200 species. A new Animal Conservation study indicates that the common eastern froglet, Crinia signifera, can carry infections without experiencing mortality. Therefore, the presence of the froglets at sites where species have become threatened or extinct inhibits efforts to reintroduce these species.

A recent assessment of higher tier studies on the toxicity and risks of neonics in honeybees by Solomon and Stephenson reported a colony-level NOAEC of 25 μg/kg (ppb) for imidacloprid and clothianidin. The toxicity of these insecticides to honeybees is however known to be reinforced with chronic exposure, and extrapolation of time-to lethal-effect toxicity plots compiled from published studies indicate that an imidacloprid level of 0.25 ppb, i.e. one-hundredth of the reported colony NOAEC, would kill a large proportion of bees nearing the end of their life.

Bees and butterflies are experiencing widespread population decline, creating public concern in recent years. Data collected in Germany suggest that it’s not just bees and butterflies at risk: insect populations overall have plummeted by more than 75 percent since 1989. Scientists have known about the population decline for several years. However, they didn’t know how many species were declining, and they didn’t expect it to be happening so fast.

Amphibians, a unique group of vertebrates containing over 7,000 known species, are threatened worldwide. A 2004 global assessment found that nearly one-third (32%) of the world's amphibians are threatened, representing 1,856 species. Amphibians have existed on earth for over 300 million years, yet in just the last two decades there have been an alarming number of extinctions, nearly 168 species are believed to have gone extinct and at least 2,469 (43%) more have populations that are declining.