Expanding populations of toads shit in the woods

A recent study by CIB MSc student, Carla Wagener, and CIB researcher John Measey, found that the gut microbiome on invasive toads shifts in expanding populations. 

The study, published this month inMicrobial Ecology, examined the faecal microbiome of three invasive populations of the Guttural Toad,Sclerophrys gutturalis, Mauritius, Reunion and Cape Town, as well as their origin population in Durban. The Mauritius and Reunion populations, despite being introduced ~100 years ago, contained a microbiome that most closely resembled the native Durban population. 

Guttural toads from Cape Town had the most distinct microbiome recorded for these toads. Although this population is only ~20 years old, the animals are believed to have arrived accidentally in Cape Town as eggs or tadpoles. This would mean that the gut microbiome of the adults was acquired after metamorphosis in their new environment. Moreover, toads collected from the periphery of the invasion were found to have a microbiome that had shifted from those at the invasion core. 

This is the first time that a study has shown rapid alteration of the faecal microbiome during a population expansion, such as that during the movement of individuals during an invasion. It seems likely that this difference is due to the proximity of other Guttural Toads during the expansion process. 

Read the article here:

Wagener, C., du Plessis, M., Measey, J. (2021) Invasive amphibian gut microbiota and functions shift differentially in an expanding population but remain conserved across established populations.Microbial Ecologyhttps://doi.org/10.1007/s00248-021-01896-4

A session dedicated to the Guttural Toad (Sclerophrys gutturalis)

The Conservation Symposium (1-4 November 2021) had a special session on the morning of 4 November 2021 where five MeaseyLab members presented their work on Guttural Toads. Because these presentations were recorded ahead of time, we are able to share them for your interest in a playlist here.

The humble guttural toad (Sclerophrys gutturalis): Lessons of plasticity and adaptation following invasion: John Measey

Introduction of guttural toads (Sclerophrys gutturalis) produces marked shifts in the endemic western leopard toad (Sclerophrys pantherina) gut microbiome: Carla Wagener

Does urban adaptation enhance invasiveness? A case study of tadpoles of a successful invasive amphibian: Max Mühlenhaupt

Conqueror toads: Comparing behaviour, performance and competitive potential in a successful invader and its native congeners: Andrea Melotto

An army marches on its stomach: Diet composition and prey preference of guttural toad (Sclerophrys gutturalis) populations along a native-invasive and natural-urban gradient: Sam Peta

The session was well attended with 140 people online. You may recognise some of the people below who showed up to face the questions...

Catch Xenopus in the Matroosberg

Although we had already collected African clawed frogs ( Xenopus laevis ) at 3,300 m asl in Lesotho (see here), at 1650 m asl in Sutherland (see here), these only represented two of the clades in the region. In order to get animals at high altitude from the southeastern clade, we needed a high altitude site with African clawed frogs. Happily, the areas around Matroosberg are at 1,300 m asl, and we managed to find frogs at the farm and in a mountain stream.

The stream water is a deep 'tea brown' from the phenols that come from the fynbos in the mountain catchment. The pools in the stream were several meters deep. That's a long way down for a trap to sit. 

As you can see, we missed one frog as it escaped from the trap as we pulled it from the water. But there were more than enough animals captured to complete the sample size that we were looking for.

African clawed frogs from the Southwest altitudinal transect

Any attempt to collect animals across an altitudinal transect is going to involve going high and low. Getting high, often involves getting cold, and that's exactly what we got when we made our highest collections at Sutherland. In driving rain, and temperatures below 10 C, we managed to get a good sample of frogs from ~1600 m asl, just outside of Sutherland town. 

From there it was down hill. We collected tadpoles using a colander in Prince Albert, drove through the Swartberg Pass, and finally ended up in the beautiful Nature's Valley where we captured the first ever record for Xenopus laevis   from the area, as well as completing our sampling and our transect. At every stop, we unpacked huge suitcases to form a fully functioning lab to make sure that the samples were tip top.

The research was driven by Boissinot Lab postdoc Dareen Almojil, who will stay on in Stellenbosch for some more sampling. Also featured is the very able Sandra Goutte, and of course, the Boissinot Lab boss, Stephane Boissinot.

Read about the Northeastern transect that was completed in March 2021 with Laurie Araspin and Carla Wagener here.

We look forward to seeing what comes of these samples once they are sequenced back in NYU-AD!

A talk for Stellenbosch University library

I was invited by the library at Stellenbosch University give a talk for their Open Access week. The theme was UNESCO's "It Matters How We Open Knowledge: Building Structural Equity."

As this theme fitted perfectly with my forthcoming book "How to publish in the Biological Sciences", I provided a talk giving a brief outline of the state of publishing.