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Rapid adaptation of French Xenopus

15 September 2020

Laurie's new paper shows rapid adaptive shifts for invasive Xenopus to cooler France

In the first paper of her PhD, MeaseyLab student Laurie Araspin (jointly supervised by Anthony Herrel of the NMHN Paris) shows how adult Xenopus laevis introduced to France in the 1980s have already shifted their temperature dependence of locomotor performance.

The work has particular interest as it shows how rapid adaptations in invasive species allows them to function in different environments to that of their native range. In this study, Laurie used adults collected from the South African Cape and subtropical KwaZulu-Natal (watch a video of that collection here). Despite these massive differences in collection localities, once they were acclimated in the lab there was no difference in their performance. The French animals, however, maintained a massive difference left shift (to cooler temperatures) in their thermal performance. 

This is just the start of Laurie's exploration into the rapid adaptive physiological shifts shown by invasive populations of X. laevis when compared to their native South African populations. Despite COVID restrictions, Laurie's work continues in Paris and in 2021 we hope to have her in South Africa sampling some of the more extreme environments for African Clawed Frogs.

To read the paper in full:

Araspin, L., A. Serra Martinez, C. Wagener, J. Courant, V. Louppe, P. Padilla, J. Measey and A. Herrel (2020) Rapid shifts in the temperature dependence of locomotor performance in an invasive frog, Xenopus laevis, implications for conservation. Integrative and Comparative Biology   60(2):456–466 pdf  

  Frogs  Lab  Xenopus

James & Natasha present in Canada

12 September 2020

MeaseyLab at the 7th Annual Meeting of the Canadian Herpetological Society

Drs Natasha Kruger and James Baxter-Gilbert both presented their work at the 7th Annual Meeting of the Canadian Herpetological Society online today. 

Perhaps the most remarkable event was that Natasha's talk coincided with local loadshedding (a South African term for a scheduled electricity blackout). Natasha then delivered the entireity of her presentation using her phone as a modem and with a flashlight on her desk. Super impressive!


There was a great shuffling of seats and reaching for (Canadian) beer when Natasha settled down to give her presentation on perceptions of predators for invasive African Clawed frogs in France


Natasha Kruger, Anthony Herrel, Jean Secondi, and John Measey

Invasive species are exposed to novel predators after their establishment in a novel environment. Defences against novel predators may not be efficient at least at an initial stage. The presence of an anti-predator defence is an important parameter that may determine the ability of local communities to control the expansion of invasive populations. The African clawed frog, Xenopus laevis, is a globally invasive amphibian. In western France it faces predators functionally similar to predators found in its native range (South Africa), however, its invasive range has expanded to overlap the range of an invasive crayfish predator. We tested whether naïve X. laevis tadpoles from the invasive French population exhibit anti-predator response to local predators, and whether the response depends on the degree of relatedness with predators encountered in the native range of the frog. Alternatively, if naïve tadpoles may express generic neophobia to any cue they are not familiar with. We exposed naïve lab-reared tadpoles to a non-predator water snail, Planorbarius corneus, a native beetle, Dytiscus dimidiatus, and an invasive crayfish, Procambarus clarkii. Species of the Dytiscus genera are present across southern Africa while no related species to crayfish occur in X. laevis’ native range. We found that X. laevis tadpoles innately reduce their activity when exposed to D. dimidiatus and P. clarkii stimulus cues. The innate response to P. clarkii indicates that X. laevis tadpoles are not naïve to the invasive crayfish. Thus, limiting the effects of these predators on the control of X. laevis, however, previous studies have found that P. clarkii mitigate the effects of other invaders. The complex interactions between co-invaders are essential to explore.

Then James provided his overview on the rapid exolution of size in invasive island populations of Guttural Toads:


James Baxter-Gilbert, Julia L. Riley, Carla Wagener, Nitya. P. Mohanty, and John Measey

Island ecosystems have traditionally been hailed as natural laboratories for examining phenotypic change, including dramatic shifts in body size (e.g., island gigantism or insular dwarfism). Similarly, biological invasions can drive rapid localised adaptations within modern timeframes. Here we compare the morphology of two invasive guttural toad (Sclerophrys gutturalis) populations in Mauritius (est. 1922) and Réunion (est. 1927) to their genetic source population from Durban, South Africa. We found that female toads on both islands were significantly smaller than mainland counterparts (reduction in body size by 33.9% and 25.9%, respectively), as were males in Mauritius (22.4%). We also discovered a significant reduction in the relative hindlimb length of both sexes, on both islands, compared to mainland toads (ranging from 3.4 - 9.0%). Our findings suggest that the dramatic reshaping of an invasive amphibians’ morphology, leading to insular dwarfism, can result in less than 100 years.

James and Natasha during the meeting with their fellow delegates

...and who could forget how James dressed up for his travelogue. All in the name of the show folks...

Everything you ever wanted to know about Indian Bullfrog invasions

10 September 2020

All about Indian Bullfrog invasions

Sometimes is great to have all the information in one place, and here we can see a great example of this with a synthesis of research on the Indian Bullfrog by Nitya Mohanty. In this study, Nitya partnered up with Angellica Crottini who had extensive data about the bullfrog invasion on Madgascar, and Raquel Garcia who introduced the SDM modelling know how. 

In this paper, Nitya suggests that these bullfrogs are potential problems in more parts of the world, should they be introduced there. This is an important lesson in a time when we are still seeing the intentional introduction of American Bullfrogs for farming in different parts of the world.

Hopefully, this publication will highlight the potential problems of the Indian Bullfrog, and it won't end up being introduced to lots more places.

Read the entire article here:

Mohanty, N.P., Crottini, A., Garcia, R.A. & Measey, J. (in press) Non-native populations and global invasion potential of the Indian bullfrog Hoplobatrachus tigerinus: A synthesis for risk-analysis. Biological Invasions pdf

  Frogs  Lab

A talk on Cane Toads by Georgia Ward-Fear

30 August 2020

A talk on Cane Toads - by Georgia Ward-Fear

At the end of 2019, Georgia and I began writing a chapter together on ethics in amphibian invasions. This turned out to be quite an undertaking, and it was a great privaledge to work with Georgia on this now accepted manuscript (see here for link to come...). I mentioned to Georgia that I was giving a class on Invasion Biology to our 3rd year undergraduates at Stellenbosch University, and she immediately volunteered to give them a talk all about Cane Toads. She recorded this ahead of time, and so I share it with you below:

Cane Toads have become a specially important group to the MeaseyLab since we started studying Guttural Toads some five years ago. The two species both belong to the family Bufonidae, but are not otherwise closely related. However, both being large bufonids we became interested in whether the same adaptations that have been extensively researched in Cane Toads could also be found in Guttural Toads. Indeed, so much work has now been done on Cane Toads, that we can use this as inspiration for questions for a long time to come.

Thanks so much to Georgia for stepping forward and volunteering to present for the BDE345 students - I'm sure that they really appreciated it. You're a star!

Opinion piece: HAA

29 August 2020

Time to speak out...

Late in 2019 I was doing some field work and found myself sitting in a car chatting with someone from another SA lab about their experience at the latest herp meetings in September (see here) and October (see here). I was shocked by what I heard as the experiences of this person had been so different than my own. They felt that they were not welcome and that other attendees has actually made them feel unwelcome by making comments about the way they dressed. I talked to more people about the meetings and was again surprised to hear that this wasn't an isolated incident but that several more people felt that the atmosphere was not welcoming. I asked whether they felt that something should be done, and they said that they felt it should be raised but that it would be better raised by someone more senior as they didn't feel  that their opinions would be taken seriously. So over the summer I wrote a piece for the African Herp News that tried to set out the experience of these folk and how this fitted into a general backdrop in science, technology, engineering and mathematics (STEM) subjects that have been dominated by white men. 

Early in 2020 a number of other things happened. A commentary published in the South African Journal of Science (SAJS) by Nicoli Nattrass entitled: "Why are black South African students less likely to consider studying biological sciences?" inflamed the South African biological sciences community as it purported to explain the continued biased racial uptake of biological sciences in South Africa from a poorly devised and sparsely sampled survey. My opinion is that in view of the contents, this piece should never have been submitted, and that it was particularly poor editorial judgement to publish it in SAJS. The backlash resulted in a great many popular articles written, as well as a special issue of SAJS with responses (seehere for some great responses). Unsurprisingly, this very public outpouring was only the tip of a much larger undercurrent of discussions that began in South African departments of Biological Sciences up and down the country. 

Meanwhile, the police killing of George Floyd in the US city of Minneapolis (seehere) saw a resurgence in the international movement #blacklivesmatter that resulted in many groups and organisations thinking again about their history. For example, the Board of Governors of ASIHvoted to change the name of their society journal fromCopeiatoIchthyology & Herpetology

But the old voices in STEM still persist and to some extent there has been a push back against the tide of inclusivity that has swept the world. It is important that we don’t let these voices advocating the persistence of power to a predominantly white male elite continue. Instead, I encourage you to lend your support ( to open up the wonderful world of STEM to be completely inclusive of the diversity of human thinking and ingenuity available. After all, we need everyone we can get to solve the increasingly complex problems of our modern world.

Here is the text of my piece recently published in the HAA newsletter:

Measey, J. (2020) Make everyone welcome in our HAA. African Herp News 74: 40-43. pdf

Make everyone welcome in our HAA

When you read the new HAA Code of Conduct last year, did you think that it was addressing an active problem in our society? Did you feel that it meant you’d have to change your behaviour at HAA (or other) meetings? When I made comments on the draft code after it was circulated in April 2019, I knew that it was well intentioned, but I wasn’t sure that it was needed. As a result of talking about these issues with colleagues, and becoming more aware of how a mainstream culture has suppressed a huge diversity of people in many sectors of science, technology, engineering and mathematics (STEM disciplines), I now see that the Code of Conduct is needed for the HAA, and more broadly to make our working environment more professional. Moreover, many of us need to reflect on our own past behaviours to make the HAA a more welcoming place to a greater diversity of people. In this piece, I aim to place some of these issues into the context of how the HAA Code of Conduct is applicable to each one of us. The mainstream culture that permeates STEM disciplines affects behaviours still seen in our meetings, interactions through peer review and our collaborative circles. 

As I talked to more colleagues I became aware that at our own African herpetological meetings, comments are made that make people feel uncomfortable and unwelcome. When I first heard these points being raised, I did so with the feeling that they surely couldn’t have come from the same HAA meetings that I attended. Could it really be that inthe same herp communityothers were experiencing comments that they thought were snide,unwelcoming, or ignorantasides?For example, having an encyclopaedic knowledge of African herpetofauna, as some of our members do, should never be used as a barrier to exclude others from conversations or discussions. Instead, that knowledge should be used to encourage others to join our HAA community. Comments on how someone’s appearance isn’t appropriate for African herping might not make you feel unhappy, or be the one thing that you remember at the end of the day’s meeting, but they do to other people. That funny picture that you included in your presentation of a bunch of scantily clad people in the field: did it make everyone laugh? Or did you just alienate half of your audience? 

Our new code-of-conduct, ratified by the HAA membership, is very clear in this regard. The following section is taken from the section on “Courtesy and respect” (HAA 2019:19)

“The HAA characterises unwelcome behaviours as those which are offensive, intimidating, malicious or insulting, an abuse or misuse of power through means intended to undermine, humiliate, denigrate or injure the recipient, or sexual advances and other actions that cause embarrassment, fear, humiliation or distress.”

This isn’t an attempt to take all the fun or laughs out of our meetings, but more thought, care and reflection is needed on how we conduct ourselves, as it does affect how other people feel (no matter what was intended). Instead, we need a culture that welcomes and unites in our strengths, interests, and generates enthusiasm for African reptiles and amphibians. Knowing that there are these problems at our meetings is important, because once we acknowledge the presence of a problem, we can start to tackle the issues involved. Societies all over the world are losing members, and this is also true of our own HAA membership. If we want to retain as many people as possible, then we need to make every single person feel welcome within our organisation.

The problem is clearly widespread, and permeates a number of aspects of academia.On December 12th 2019, a study published inPeerJunveiled an inconvenient truth about peer review. Silbiger & Stubler (2019) obtained responses from >1000 scientists in STEM disciplines about their experience with unprofessional peer reviews, showing that 58% had received such responses. Their questionnaire went on to ask what impact scientists felt that such reviews had had on their aptitude, productivity and career advancement. The results were fascinating, and they throw some important light on a real problem that we have in our own area of science. Essentially, people with demographics over-represented in STEM disciplines had little or no problem with the comments, but under-represented groups perceived them as being negative. Knowing that there are these problems in peer review is important, because once we acknowledge the presence of a problem, we can start to tackle the issues involved. 

So, why do scientists make disparaging or unprofessional remarks to their colleagues in peer review? Whenever two or three scientists get together, you hear tales of recent woes associated with peer review. The retelling of such stories is all part of the collective, cathartic unburdening of what can be a traumatic experience especially when we put so much effort into each piece of work (see Hyland & Jiang 2020). Reading through a lot of these reviewers’ comments, I can see that there is an attempt at humour  (see This humour is not appreciated by those who receive the reviews. Perhaps I understand the humour, because I also come from that same culture that dominates STEM, but that is not understood or even recognised as humour by others. Writing humorous reviews is unprofessional, especially if it is used to accentuate negative aspects. Needless to say, we could all do without unprofessional reviews. But this problem with peer review is illustrative of the problems at our meetings; we need to be more inclusive.

Last year, I was privileged to attend a presentation in which Karen Warkentin (2019) talked about the amazingly diverse world of herpetology, and how diversity enriches not just what we study, but increases the perspectives and insights of what we choose to study and how we study it. I was personally inspired by her call to collaborate diversely to produce diversity within our own research. It was one of those presentations that made me reflect, recognise times when I might have been not-inclusive and decide to change, and also to encourage others to make a change toward inclusivity. We all need to think more about welcoming everyone into the wonderful world of herpetology. We need as many members as we can find. 

At the heart of our actions should be the science that we do, and sharing the knowledge base that is so rich in our association. I have benefitted massively from local knowledge, and from HAA members that had already spent a lifetime working with this diverse but polyphyletic group. I feel very privileged to be employed to work on these animals, and I receive monthly reminders in the form of pay-checks that underline exactly how fortunate I am. Being employed comes with the responsibility to act as a professional first, at the cost of sharing a joke at a meeting or an attempt at humour in peer review. The upside is that there is more to be gained from being inclusive, and profiting from the diversity of herpetologists as there is in being engaged in the amazing diversity of African herpetology.

In the HAA, we cannot afford for those under-represented in STEM subjects, especially our junior members, to be repelled and estranged at our meetings, excluded from collaborations or alienated by peer review. Humour can do this, because what you find funny might well be offensive or misunderstood by someone else. We want to retain our image as a friendly and welcoming association, but not at the cost of the diversity of African herpetologists, or through leaving behind our professionality. And before you dismiss this article and feel that it must apply to someone else, please reflect and think again. 


HAA 2019. HAA Code of Ethics and Conduct. African Herp News. 71: 18-20.

Hyland, K. and Jiang, F.K., 2020. “This work is antithetical to the spirit of research”: An anatomy of harsh peer reviews. Journal of English for Academic Purposes, 46. 

Silbiger, N.J. and Stubler, A.D., 2019. Unprofessional peer reviews disproportionately harm underrepresented groups in STEM. PeerJ, 7, p.e8247.

Warkentin, K. 2019 Queering Herpetology: On human perspectives and the study of diverse animals – Plenary for the Brazilian Congress of Herpetology, Campinas, SP, Brazil, July 2019: 

Post Script

Since writing this piece in April 2020, a number of global and regional events have highlighted the need for awareness of the inequalities still present in herpetological communities. While at the HAA we may not need to change the name of our journal, the Board of Governors of ASIHvoted to change the name of their society journal fromCopeiatoIchthyology & Herpetology. We should still use this time individually and collectively to reflect on how the inequalities of the past can be corrected to improve our association today.

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