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Does aquatic performance = terrestrial performance?

15 December 2023

Laurie's work comes to fruition... again

It only seems a few weeks ago that Laurie was defending her thesis in Paris (see here), yet here comes a product of that exceptional work. By now we are all familiar with the African clawed frog, Xenopus laevis, and we know that it has to move overland between ponds in order to disperse (see Measey 2016). Otherwise, these frogs spend most of their time in water swimming around, finding food, mating and otherwise going about their lives. So when it comes to performance, we might expect that as they spend such a large portion of their time in water, they perform better there. In addition, their morphology suggests that these animals should be much better at performing in water.

Laurie measured the performance traits of African clawed frogs, using animals collected from the invasive population in France and those from iSimangaliso National Park in KZN. The results, shown in the figure below, are really clear. The frogs were found to perform equally well on land and in water. In fact, individuals that performed better on land also performed better in water. This suggests that there is no trade-off between some animals who do better in water, but worse on land.

Our findings did not meet our expectations, but what this shows us is that these animals do not have morphological specialisations that are exclusively for aquatic environments. Again this finding goes against the commonly held view that these are purely aquatic frogs, and instead shows that they are adapted well for moving on land.

This will not be the last we hear from Laurie or the products of her thesis.

Read more:

Araspin, L., J. Measey and A. Herrel (in press) Does aquatic performance predict terrestrial performance: a case study with an aquatic frog, Xenopus laevisJournal of Experimental Biology   jeb.246545. pdf

Measey, J. (2016) Overland movement in African clawed frogs (Xenopus laevis): a systematic systematic review. PeerJ   4:e2474

  Frogs  Lab  Xenopus

XTBG talk on rapid evolutionary change

28 November 2023

A talk at the amazing Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences.

Few venues to give a talk rival visiting the spectacular Xishuangbanna Tropical Botanical Garden (more commonly referred to as XTBG) research centre run by the Chinese Academy of Sciences. The location is within the Xishuangbanna Dai Autonomous Prefecture in southern Yunnan Province near the border with Laos. The gardens are set on an island in a meandering river, and are host to more than 4000 species of plants, including tropical forest native to the area.

I provided a summary of the MeaseyLab work on rapid adaptation in Guttural Toads and African Clawed Frogs, which went down very well with many rapid-fire questions. Afterwards, we had an amazing meal and discussion with many researchers also working on complementary themes around rapid evolution. Thanks to my hosts Kyle Tomlinson and Ahimsa Special thanks to Yiran, Niña, Thilina and Ade for all their kindness.

It is always a pleasure to visit and meet all of the enthusiastic researchers from all over south-east Asia. There is an amazing mixture of research projects including invasive plants and animals. I’m really looking forward to my next visit.


Measey, J. (2023) What can biological invasions teach us about rapid evolutionary change? 28 November 2023. Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences

Laurie's PhD examination

16 November 2023

Laurie becomes Dr. Araspin

Those of you who follow this blog will be very familiar with Laurie Araspin as she has been the subject of lots of posts over the years (for example, see here, here and here). 

It was a rainy day in Paris and the gig didn't start well with all the normal IT problems associated with trying to marry a live event with an online audience, but Laurie braved it out and presented her thesis work to a packed auditorium. 

Finally, after the presentation was done, the jury deliberated and pronounced Laurie to be Dr. Araspin. And then the party began. 

The jury consisted of some familiar faces to MeaseyLab members past and present.

Bottom right, Carlos Navas (on screen from Sao Paulo or perhaps on sabbatical in the USA) is having his audio checked by Anthony Herrel and Laurie. Bottom left, Raoul Van Damme admires Laurie's Kamasutra des grenouilles. Top right, Jean Secondi poses with a friend he found at the party. Top left, all jury members have lunch before the presentation (Sandrine Meylan, Laurent Coen) and online joined by Hannes van Wyk from South Africa. 

It was also fabulous to meet Lauries family and friends who supported her throughout her academic journey. 

The examination of a PhD is the end of a long journey and also a time to reflect on a set of great work accomplished by an individual working within a team. Laurie well deserves her new title, and we look forward to seeing what she will do with it.

Read the thesis:

Araspin, L. (2023) Thermal adaptation in an invasive frog (Xenopus laevis): impact of temperature on locomotion and physiology. PhD thesis. MNHN and Stellenbosch University

  Frogs  Lab  Xenopus

New insights on metamorphosis

16 September 2023

There's a frog in my tadpole

Sometimes a photograph can instantly give you a whole lot more information on a topic than you ever knew. 

This is a cropped close-up of a picture that I showed on the blog a few weeks back (see here). At the time that I took the picture, and later when I selected it for the blog post, I had completely failed to spot this metamorphosing frog in the image. I had never fully appreciated how the new frog in a metamorphosing tadpole was formed. Perhaps because of the colour of this Xenopus laevis frog from an invasive population in Tucson, Arizona, is so stark, you can clearly see through the transparent tadpole flesh the form of the frog coming through.

Note how the head of the tadpole and head of the frog appear to be completely different, yet the sensory organs (eyes, nares, etc.) are functioning on the tadpole and joined by nerves to those same sites on the frog head. Note also the way in which the fore-limbs (that always appeared to come at an odd place on the tadpole) are perfectly situated in relation to the frog head. 

Over the next week or so, the tadpole head will regress in size and the tail will start to shrink as the final stages of metamorphosis take place. Sensory organs will relocate into the frog head. 

  Frogs  Lab  Xenopus

Revisiting the Arthur Pack Desert Golf Course, Arizona

30 August 2023

Back catching Xenopus in Tucson, Arizona

In 1995, during my PhD at Bristol University, I visited Tucson Arizona to study the population of African clawed frogs at the Arthur Pack Desert Golf Course. The population is known to have dated to the late 1970's when a local academic seeded many impoundments in southern Arizona with Xenopus hoping that he could pick up breeding animals in the future for selling on. It seems that most of the introductions were failures, but at this one golf course the population took hold.

Back in 1995,  it was really hot when I visited this site, reaching 47 C on one of the days that I was there. That's still the hottest I've ever experienced.

I've long wanted to return to the site, and so I made it a priority on my North American leg of my world Xenopus tour.  

The picture above is from 1995 and is the southernmost lake on the golf course, featuring a canoe which I was allowed to use to paddle around this lake and set traps.

This is the same site now. The willow tree is gone, but you can see the same wall above the lake.

The canoe is still around and once again I was allowed to use it and paddle out to a pole in the deepest part of the northernmost lake to set some temperature loggers.

I remember the last time I sat in that canoe in 1995 a golf ball whizzed passed my ear making me very pleased that I was wearing a hard hat. 

With the help of Becca Cozad and her ARC crew: Karen & Maya, we were able to quickly run through the catch and process all the animals needed from Arizona. We were also joined by Randy Babb who bought his seine net which made really short work of bringing in a lot of tadpoles for sampling.

A special thank you to Brian Stevens and all his staff for making us so welcome at the Crooked Tree Golf Course. They really pulled all of the stops out and went out of their way to make sure that this was a successful mission. Strapping a canoe to the top of a golf cart and driving it across the course was unforgettable. We really are most indebted to them all.  

  Frogs  Lab  Xenopus
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