French Guiana 2015: What, where, why?

So two weeks later, and fieldwork is complete! We’ve collected swabs and, in many cases, toe clips from 286 frogs and one cecilian, covering over 12 species during 11 collecting days.

What we sampled:

70

In addition to these, we swabbed 1 Adenomera andrese, 1 Leptodactylus langirostris, 1 Anamoglossus rivicolus (scientific description of this species is not yet compete), and 1 Hypisboas boans.

What we did:

We swabbed every individual to test for the presence of Bd using the standard diagnostic of qPCR. We’ll also be testing these swabs with a new qPCR diagnostic which can indicate the likely lineage of Bd in the sample. From some individuals we also took toe clips to attempt to isolate live Bd zoospores for culturing and genomic sequencing. The toe clips (or tadpole mouthparts) were cleaned in agar plates with antibiotics and then put onto plates of solid media or tubes of liquid media. After this it’s a case of watching them closely every day, throwing away any that show sign of contamination with other microorganisms, and keeping any that look promising safe until they can be looked at under a microscope in the lab!

Cleaning toes
Cleaning toes and taking swabs

Where we sampled:

The samples were taken at a range of altitudes, from under 100m asl, at the Pararé camp, to above 400m asl, at the top of the Inselberg.Some of the species were found across the entire altitudinal gradient, some had a restricted altitudinal distribution.

IMG_6111
The top of the Inselberg, our highest sampling point
OLYMPUS DIGITAL CAMERA
At a low altitude sampling point, a river valley

Why?

Bd has been detected in French Guiana within the Nourages Reserve, but it’s never been isolated and cultured and the lineage has never been typed. The aim of the study is to see what chytrid is present in the reserve, to isolate and culture that chytrid if possible (from toe clips and tadpole mouthparts) and to use DNA from the swabs to test for presence or absence of Bd and the most likely lineage using new qPCR diagnostics.

Next steps are to keep watching the cultures for contamination or zoospores and extract the DNA from the swabs for qPCR testing and keeping fingers firmly crossed!

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