The science behind an 'uncrushable' beetle’s exoskeleton

Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week, the diabolical ironclad beetle…

Host: Shamini Bundell

And inequity in science. I’m Shamini Bundell.

Host: Benjamin Thompson

And I’m Benjamin Thompson.

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Host: Shamini Bundell

The diabolical ironclad beetle is, as the name might suggest, pretty tough. There have been reports of these insects being run over by cars and just shrugging it off and continuing about their beetley-business. For that reason, researchers have been very interested to discover the secrets of the diabolical ironclad beetle’s toughness, as Geoff Marsh has been finding out. First, here’s the Natural History Museum’s beetle curator, Max Barclay, speculating on how this hardy bug got its name.

Interviewee: Max Barclay

So, the diabolical ironclad beetle is quite a large beetle that is usually found in the Southwestern United States, and you get them along the Pacific Sea border of places like California. Now, the diabolical ironclad beetle was named by somebody called John Lawrence LeConte, and it’s obviously only speculation as to why he would have given it the name diabolicus, associated with devils or hell. It could be because it’s a sort of black, carunculated beetle that lives in dark places, but it could equally be because the exoskeleton of this species is so hard. Of course, entomologists preserve specimens by putting them on pins, and getting a pin to go through a specimen of the diabolical ironclad beetle is actually very difficult. I have tried to pin them before and it is extremely challenging to actually get a pin through the specimen.

Interviewer: Geoff Marsh

So, for two centuries or more, the extreme toughness of this beetle has been nothing much more than a nuisance to museum creators like Max, but more recently, these bizarre mechanical properties came to the attention of a materials scientist, David Kisailus at the University of California, Irvine.

Interviewee: David Kisailus

My student actually, Jesus Rivera, who’s the lead author on this paper, had visited an entomology museum at the University of California, Riverside, and he found out about these beetles, and we had heard from folklore, if you will, that they can be run over with a car and they don’t die and, of course, we had to test it.

Beetle versus car, take two. Still alive. Mechanically fine. Playing dead, but mechanically looks good.

Interviewee: David Kisailus

And so, we thought it was dead but then after a couple of seconds, it just started walking around again. So, we thought, wow, this beetle is super tough and we have to explore a little bit more about them.

Interviewer: Geoff Marsh

In a sense, you wanted to know, beyond those fun anecdotes you mentioned about the car and the mounting pins, exactly how tough the beetle really was. How do you do that scientifically?

Interviewee: David Kisailus

So, one of the first tests that we actually performed was taking a mechanical test stage and we basically placed the beetle on this metal plate and crushed it, and then measured the force required to crush the beetle. And of course, we had to have our control, so we looked at other beetles.

Interviewer: Geoff Marsh

What are we talking here? Give us some numbers.

Interviewee: David Kisailus

Well, I mean, in the study that we performed, it was 150 newtons of force required to crush the beetle. Other beetles only were able to get to 50 newtons, so three times stronger. So, for example, folks say that you can take your thumb and your forefinger and you can squeeze as hard as you can and you won’t be able to crush these beetles. The force that they can withstand before failing is 39,000 times their own body weight, which is pretty impressive.

Interviewer: Geoff Marsh

So, the first part was to push this beetle to its limits in your lab, but the second part was to understand what it was about the beetle that gave it this incredible toughness. What were its secrets?

Interviewee: David Kisailus

One of them, the first thing that we found, was that the edges around the elytra, these hardened forewings that we call lateral supports, actually provided, if you will, the first line of resistance to this compression, and that these structures were graded where there was more interlocking between the top half and bottom half of the exoskeleton, closer towards its organs, but that interlocking was reduced as you moved towards the tail end, which enabled the beetle to squeeze under rocks or in between bark.

Interviewer: Geoff Marsh

So, it has a bit of sort of suspension at the back, but at the front end where it needs to protect all its internal organs, it’s really rigidly held together.

Interviewee: David Kisailus

Indeed, that’s a perfect way of saying it. It’s more rigid near the organs and more giving near the tail end. And the other architectural feature that we discovered within this beetle was essentially where the two halves of the elytra are joined, the two halves are actually stitched together using this architecture where you have these bulbous structures that are integrated with the female side.

Interviewer: Geoff Marsh

I would have assumed that was a kind of weak spot.

Interviewee: David Kisailus

Yeah, you would imagine the failure would be at the seam, but indeed, that’s actually what we investigated, the sutural region. In fact, when my student first showed me the micrographs, we found that it looks very much like a jigsaw puzzle. So indeed, the reason it doesn’t fail at this interface is that it has this bulbous, jigsaw puzzle-like architecture that really provides a lot of strength to keep it from pulling apart.

Interviewer: Geoff Marsh

What is it about that that gives such toughness and strength to its forewings?

Interviewee: David Kisailus

Yeah, so we actually used some 3D printing to look at the different geometrical features that an interlocking structure might have, where we varied the angle of this ellipsoid, if you will, and what we found was that there was an ideal angle, that if you had two large an angle, it was too bulbous, let’s say, then upon pulling it, the neck region of that bulbous structure would fail. And in fact, it led to our next discovery, which was quite critical. When my student performed some experiments on the elytra in the synchrotron where we pulled it apart in situ, we actually found that those bulbous structures, those sutures, actually were not solid homogeneous pieces of, let’s say, a protein, but rather they have a microstructure within it that allows them to locally fail or slip. They have some give so that they don’t catastrophically fail but rather they fail locally within the blades or the sutures themselves.

Interviewer: Geoff Marsh

And that wasn’t the end of your experiment, was it, because you then wanted to see if you could be inspired by those architectures that you’d found in the beetle and make your own kind of bioinspired material and test your ability to improve toughness, and it worked, didn’t it?

Interviewee: David Kisailus

Indeed, and we realised there’s some issues in, for example, the aerospace industry where the newer aircraft are now integrating a lot of composite materials, carbon fibre reinforced plastics, into their air frames. So, how do you actually fuse carbon composite to, let’s say, an aluminium structure? And so, people will use rivets and fasteners and other types of structures to bind these two structures together and often, those structures will fail. So, we actually fabricated carbon fibre composites that mimicked the bulbous structure from the suture of the beetle, and joined it to an aluminium piece and compared the strength and toughness of this structure versus a standard aircraft fastener, and found that it had similar strength to an aircraft fastener that they actually had 100% more toughness than the aircraft fasteners, and the implication of that is, of course, it means they’re more reliable, that they would not fail catastrophically but they would fail more gracefully, which means that if an aircraft had some issue, people inspect these parts and you might actually see, oh, there’s damage, we should replace this, rather than catastrophic failure occurring.

Interviewer: Geoff Marsh

So, you translated some of those macro-architectural findings, that jigsaw shape of the blades, into your own engineered structures and that seemed to work pretty well, but what about those micro-structural details you saw within the blades in the beetle, those laminated layers that stopped those interlocking structures snapping at the neck? Can you mimic those micro details?

Interviewee: David Kisailus

In fact, that’s the next part of our study, Geoff, is to understand what are the proteins? Are they hyper-elastic? Do they allow for extreme extensibility? So, it could be a polymer, for example, that’s hyper-elastic, but we need to understand what these components are made of within the beetle. I think that’s the next step, to really understand the material components and determine whether or not the material components are, what role they play and whether or not we can translate that into perhaps new materials. That might be a different avenue that would be beyond these macro- and micro-architectures, for sure.

Host: Benjamin Thompson

That was David Kisailus from the University of California, Irvine in the US. To test the strength of your knowledge on these hardy beetles, you can find a link to his paper over in the show notes. Next up, it’s time for our weekly update on the coronavirus. It is, of course, Coronapod, and this week I’m joined by Noah Baker and Ewen Callaway. Hello to you both.

Ewen Callaway

Hi there.

Noah Baker

Hi Ben.

Host: Benjamin Thompson

Now, we’ve talked a bunch about vaccine trials here on Coronapod, how they’re done and the issues surrounding them – and one of those is they take an awfully long time, correctly, of course. But there’s been an announcement in the UK this week that’s maybe trying to shortcut how long a vaccine trial takes, and it’s not something we’ve talked about on the show before, and it’s called a challenge trial and, Ewen, it’s something that you’ve been looking at. What is a challenge trial?

Ewen Callaway

Yeah, a challenge trial, or a human challenge trial in this instance, is an experiment where you intentionally infect or challenge volunteers with an infection, and then you follow the infection and see how it develops, and in some cases, you may want to study whether you can modify the course of that infection with either a therapy or, as you suggest, with a vaccine. Yeah, it’s a way of studying human infections in a very, very controlled setting.

Host: Benjamin Thompson

And as I said, there’s been an announcement in the UK this week about one that’s going to be undertaken. What can you tell us about what this trial is and what does it look like?

Ewen Callaway

Yeah, human challenge trials are kind of bread and butter for infectious disease science. They have decades, even centuries, of history. The announcement in the UK is that the UK government’s vaccine taskforce has announced an intention to fund a challenge trial for COVID-19, and it’s not definitely going forward – it still needs to have regulatory and ethical approval – but it seems like the ducks are lining up and they’re hoping to move forward on this challenge trial. I guess the way it will work initially, before you go about testing vaccines or therapies – in this case, I think the focus will be on vaccines – you need to figure out what to expect from your challenge. So, they’re going to be establishing what dose of SARS-CoV-2 to infect people with and what kind of response you get from that, so that way you can know, if you’re giving someone a vaccine or a therapy, whether you’re changing the course of that natural progression. These experiments are only open to young, healthy people. I think 18-30 is the target range for this group, so those people who are at lowest risk of severe disease and death. But as I write in our story, it’s kind of unchartered territory. We’ve done challenge trials for lots of diseases that can be deadly, but they’re things that we know more about, like malaria and influenza, cholera, for example. So, this is, I think in some ways old, and in some ways quite new, and I think that’s why it might be a little bit controversial.

Noah Baker

I’m kind of interested in this, right. I would really like to talk a little bit about the participants. But before we get to it, I guess I’m kind of keen to know what researchers are hoping to gain out of this that they aren’t going to gain from the many vaccine trials that are ongoing because phase II trials are partially designed to work out an appropriate of vaccine, phase III trials are there for efficacy. There’s quite a few advanced vaccine trials. Why do we need the challenge trials at this stage?

Ewen Callaway

I don’t know if ‘need’ is the right word. I think there are a lot of people, including people who have conducted challenge trials on other infections, who say that the time might not be yet right, that we don’t know yet enough about the disease, that we don’t know enough with very, very high certainty guaranteed that people will not get sick or die. But those people who are I wouldn’t say advocating is the right word but think that now is the time say that they’re not a replacement for these phase III field trials of vaccines that you’re talking about. They’re kind of a supplement. They go hand in hand, maybe, and we’ve got I don’t know how many phase III trials ongoing – half a dozen at least, I guess – and they’re going to deliver results, and hopefully they’ll be smashing successes. If they are smashing successes, it might be a little bit more difficult to test additional vaccines because you’ve got an effective vaccine so why do you go to the expense and trouble of running another very large, costly trial, and so some people have suggested that challenge trials could be a way of vetting this kind of next generation of vaccines or comparing the efficacy of vaccines side by side. Another thing is that challenge trials – because you know exactly when you give somebody an infection – you can very closely monitor their body’s response to both the infection and the vaccine and correlate those two in a much, much more powerful way than you can in a field trial. You could use them to predict whether other people might respond well to a vaccine without having to run a large trial, so that’s an important insight that you can get from a challenge trial that people touting them up are saying.

Host: Benjamin Thompson

It does seem like useful information then, potentially, Ewen, but it also seems like it could be quite the ethical minefield to do this in the first place.

Ewen Callaway

Oh, yeah, for sure. Challenge trials have a long history of being run safely and ethically. I’ve spoken to some people, including bioethicists who say now is the time because you have to think about not only the risk to the participants that are in the trial, which they think can be mitigated and very low, but you also have to think about the risks of not proceeding with such a trial. Some researchers have calculated that by speeding the development of a vaccine by just a month, we could avert thousands of lives lost and many more thousands of years in poverty for people, so there’s that calculus. But then again, other people say that until we really can de-risk these trials significantly where we have a real blockbuster treatment available, we shouldn’t be running them. And maybe those things are coming soon and maybe in a year we’ll be able to run a really powerful and safer SARS-CoV-2 challenge trial. People have a lot of different opinions on this and UK government has made the decision to move forward pending regulatory and ethical approval, so maybe these trials could fall through. They may not go ahead if there are hurdles that can’t be surmounted, so we have to remember that.

Noah Baker

In the meantime, I guess one of the safety precautions that’s been suggested so far is to try to use participants in these trials that are young, that are very healthy, that are sort of deemed to be at lowest risk of developing severe infection in order to be able to try to keep this as safe as possible. But additionally, these participants will also be paid, and I suppose there can always be a concern that as soon as someone’s being paid for something then they may not completely think through the risk and it might be hard to communicate a risk if we don’t know that much about how the disease works. I mean, what kind of steps can be taken to try to make sure that these trials would be deemed ethical and safe and fine to go ahead?

Ewen Callaway

I mean, there’s a lot in there. We talked about trying to identify participants who are at the lowest risk of severe disease or death, and some people have told me that participant selection is the single biggest thing you can do to make a challenge trial safe. But the therapy you give could be really important, and some could argue that these monoclonal antibody therapies that are hopefully coming online soon could be helpful, but those are things that can make it safer. And to get to your other question about compensating participants and whether by giving them some amount of money people participating for the wrong reasons, that’s a tricky discussion. I’ve spoken with bioethicists, including bioethicists who have worked on challenge trials and surveyed people who have been involved in challenge trials for other infections, and I think the consensus is people don’t have a problem with compensating participants for their time. These are people who are economically active and they’re going to be asked to spend more than two weeks in quarantine, and this is a lot of trouble to go to so they should be compensated. And at the same time, you don’t want people necessarily ignoring the risks because of the level of compensation. You want to set the compensation so it doesn’t have to blind people. Interestingly, I spoke with a bioethicist who made me aware of some research on malaria challenge trial participants, and he said that people a have mix of motivations for participating, from pure altruism, which maybe is the purest reason, people were curious, and some people, mostly in these trials, were in it for the money, they said in surveys. And interestingly, according to this researcher, those people who were mostly in it for the money, they were more attuned to the potential risks of participating. So, there are surprises and it’s an area that is sensitive, and I think once this study goes through ethical review, it will be looked at very closely by a very broad set of researchers and experts.

Noah Baker

And the participants that are being chosen, they’re all likely to be young, healthy, deemed low risk. Does that have any impact on the value of what you learn at the end of this trial because if you’ve deliberately chosen people that are most likely to be unaffected by the virus or less affected by the virus, then how applicable are those results to the average Joe in the street or, even worse, someone who is at high risk of being affected by the virus in a severe way?

Ewen Callaway

Yeah, that’s an open and important question, and you’re exactly right. At the time being, I think we most want therapies, and vaccines especially, to prevent people from developing severe COVID, and those happen to be mostly people who are older and have pre-existing health conditions, the kind of people that you exactly would not want to participate in this trial. And so how valuable is what you learn in 20-year-olds to their infections. And I think that’s an open question, and I think the researchers conducting this study will need to demonstrate the relevance to that. One reason why they might be useful is that in the field trials ongoing for vaccines, the researchers conducting them have gone to great effort to enrol at-risk groups – people who are older and people with pre-existing conditions. It’s likely that these people will be trying to avoid SARS-CoV-2, shielding to some extent, and so when we go to look at the data, we might not have a lot of evidence of directly how vaccines protect older and at-risk participants. We might have to go on the infections mostly in these lower risk categories. That’s just speculation. And so, what people have suggested is that challenge trials might, by identifying the nature of the immune response in young people albeit that is associated with protection, they could infer in a more powerful way whether vaccines are likely to protect other groups. That remains to be shown, but that’s one possibility.

Host: Benjamin Thompson

Well, several questions then that we’ve come up with so far today. What’s the timeline on this? When do these questions need to be answered and what happens next?

Ewen Callaway

Well, the timing for these sets of trials is that, pending ethical and regulatory approval, they could begin in January, and that’s a few months away, which is a world in COVID times, so we don’t really know where it will be. Hopefully, we’ll have some phase III results so we have a better sense of what these challenge trials could tell us and maybe some questions in mind with phase III results in hand. And then I guess, going forward, the UK government hopes to be able to test vaccines in this human challenge model. I’m not aware of any timings with those. Through 2021 would be my assumption, but yeah, I think it’s going to be in the context of what happens. I should also note that the UK isn’t the only country or funder that’s looking at human challenge trials for COVID-19 or SARS-CoV-2. The US government and its National Institute for Allergy and Infectious Disease is laying the groundwork, I would say, to running challenge trials. They’re preparing special challenge strains of virus that could be given to people and developing protocols for these trials should they be needed. I think their approach is let’s wait and see how the phase III trials look and then we’ll better be able to evaluate what we could gain from challenge trials and whether it’s worth it, I guess, is what they’re telling me.

Host: Benjamin Thompson

Well, let’s leave it there, both. Let’s reconvene on this one in January and see how things are going. But for the time being, Noah and Ewen, thank you so much for joining me.

Ewen Callaway

Thanks so much for having me.

Noah Baker

Cheers, Ben. Thank you.

Host: Benjamin Thompson

More from Coronapod next time. Coming up in this week’s show, we’ll be hearing about a new book which looks at how science institutions can address ingrained imbalances in diversity and equality. Now, though, Noah’s back with this week’s Research Highlights.

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Noah Baker

Researchers have created a cellular timestamp which can reveal the age of an RNA molecule down the hour. When a gene switches on, it triggers the production of RNA molecules that carry the information needed to make proteins. By sequencing this RNA, scientists can build a picture of the cellular processes that are going on at any given moment in the cell. But that didn’t let them reliably work out when a specific gene became active, until now. The new technique tags genes with a specific genetic sequence that binds an RNA editing protein. That way, when the gene is transcribed, the RNA editing protein will detect the RNA and set to work editing it, creating more and more edits over time. Then when the researchers sequence the RNA strands, they can simply count the edits. The older the RNA, the more edits it will have accumulated. The system can specify an RNAs age to within roughly one hour. Read more over at Nature Biotechnology.

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Noah Baker

Elephant seals have helped to discover pockets of ultra-frigid seawater in the Southern Ocean, and it appears that they’re much more common than expected. Seawater generally freezes at around −1.85°C, but the icy waters around Antarctica can remain liquid at even lower temperatures. This can occur when submerged ice on the underside of ice shelves melts, generating what’s known as ‘supercooled’ water. But the extent of this phenomenon has previously been unknown. Researchers used data collected in the Southern Ocean from research ships, autonomous floats and sensor-wearing southern elephant seals to identify supercooled regions. To their surprise, up to 5.8% of the water they analysed classified as supercooled. In many cases, the ultra-chilly water penetrated down to the depths of the ocean. The authors say that these supercooled plumes could represent an important pathway for heat loss in the deep ocean that’s currently not represented in climate models. Cool. Check it out over at Geophysical Research Letters.

Host: Shamini Bundell

Around the world, organisations have been taking a long overdue look at their practices when it comes to encouraging diversity and equality. Not least in the sciences, where many universities and societies have taken up the baton and started to address ingrained historical imbalances. Julie Posselt, an associate professor of higher education at the University of Southern California, has been investigating these efforts in her new book, Equity in Science: Representation, Culture, and the Dynamics of Change in Graduate Education. Dan Fox caught up with her, and she explained why, in many cases, institutions have been so slow to change.

Interviewee: Julie Posselt

There’s a tendency to want diversity but not to want to change the rules of what they do, rather to be selecting people on the basis of rules that ultimately don’t serve historically under-represented populations. And as a result of this, you get people admitted on the margins, but then coming and checking things out and picking up on the fact that there isn’t deep change going on, so even those who have the chance to join departments often will choose to go elsewhere. So, what I wanted to do with this book was understand what’s going on in organisations that have become more diverse, either with respect to race, ethnicity and or gender. And basically, what I found is there’s lots of good work going on, but even the best-case scenarios are works in progress.

Interviewee: Dan Fox

So, before we move on to the success stories, what were the sorts of problems you were finding in general, and were these recurring problems throughout different research faculties?

Interviewee: Julie Posselt

Some of the recurring problems that I saw had to do with the ways of knowing that science encourages and values being mismatched to the kinds of social issues that were in play. So, they’re basically working within a domain where there is research about these issues, but they’re not necessarily trained to interpret that research and, in some cases, are trained to actually sort of dismiss that work relative to the natural science of research. So, one of the recurring problems is just a need for greater knowledge about what the current evidence space is. Another current problem is that in every organisation, I found that there tended to be a few people really making a case for change, championing change, and a lot of people who were quite passive in the middle and then usually a few recalcitrant folks, as you might expect anywhere. And it was as much the passivity of the people who were just leaving it to the few folks who were really invested in change as it was the recalcitrant obstructionists that were preventing real change from occurring. So, I can see this in part because in the places where there was more of a sense of collective engagement in trying to bring about positive change, the whole process was much smoother and it was much more sustainable.

Interviewee: Dan Fox

So, could you tell me a little bit about some of the success stories that you found, and do you think these are reproducible?

Interviewee: Julie Posselt

There were common patterns that I think are reproducible, even if the specifics of the organisational histories, even if the specifics of the kinds of policy constraints that they were under, varied. I’ll tell you a story about a really good one. So, this is a chemistry department that had once been ranked very highly. As you know, in the United States, they’re obsessed with the rankings. And unfortunately, as a result of failing to tenure and promote a number of women professors, they quickly and precipitously dropped in their rankings. It became this huge matter of public shame and it was the shame involved that motivated people to take a really hard look at what was going on. So, they began to look systematically at data. They began to look systematically at their policies and practices around hiring and promoting women. And very importantly, they were careful to select new department chairs at this point who were very active advocates and who weren’t afraid to take what might be unpopular steps in the interests of making change. So, as a result of this kind of learning-based process that they went through, they were really engaged not only in policy change but culture change, and because they became more confident about the change process because they were engaging deeply in it, hey were then able to translate it to graduate education. And then once they started to improve things with respect to gender, they gained confidence to begin making change with respect to race, and that’s the story, in this particular department, that’s still unfolding.

Interviewee: Dan Fox

So, what do you think STEM institutions need to do to develop the tools that they need to make these cultural changes?

Interviewee: Julie Posselt

Because the composition of so many of these departments is white and male, it means many of the people who want to be most involved don’t have the personal experience with lived inequalities, so it has to come from learning outside of their own experience. So, one of the main areas of finding a need, I think, is to develop capacity for what we call racial literacy, and racial literacy in the United States is the ability to talk openly and comfortably about the dynamics of race and racism, and to see how it’s operating in the spaces that we work within. And racial literacy isn’t something that is really encouraged at all in the United States within white communities, but I do think it’s really important. Another area of need, I think, is to have just a chance to see what the current evidence is about some of these topics. Faculty really do need access to current research and current evidence to inform even their understanding of what the problem is.

Interviewee: Dan Fox

Finally, our audience here at the Nature Podcast tends to be working scientists across a variety of fields. What would your key point for them to take back to their labs be if they were trying to tackle these sorts of problems in their institutions?

Interviewee: Julie Posselt

If there’s a single thing that working scientists can do to begin making change, it’s to engage in a combination of activity. One is reflection and, following that reflection, discussion. Find people to talk about it with and begin applying the insights that you’re getting. Really, I think, it’s simply making time for this and being willing to be a little bit self-critical. Be willing to question the assumptions that you were trained with. Be willing to question the way that you were socialised.

Host: Shamini Bundell

That was Julie Posselt. You can find a link to Nature’s review of her new book in the show notes.

Host: Benjamin Thompson

Finally on the podcast, it’s time for the weekly Briefing chat, where we discuss a couple of articles that have been highlighted in the Nature Briefing. Shamini, what have you got for us this week?

Host: Shamini Bundell

So, the story that I saw this week jumped out at me because it’s quite relevant to what Dan and Julie were talking about in our earlier segment. It’s a new story in which Princeton University in the United States has agreed to back pay wages for some female professors who may have been being paid less than their male counterparts.

Host: Benjamin Thompson

Right, and what sort of figures are we talking about and what areas of academia?

Host: Shamini Bundell

So, this is across Princeton, and it’s based on a review by the Department of Labour in the US that looked across the board and said these 106 women in full professor positions were being and are being paid less than their male counterparts. Now, Princeton doesn’t accept that finding. Their position is that this difference is because the Department of Labour were looking sort of across the board and not on a department basis. They said that they had done their own assessment and they said that according to their statistical assessment, there is no issue with the gender pay gap there. But they have agreed to back pay this nearly US$1 million and adjust future salaries in order to avoid what they said was potential lengthy and costly litigation.

Host: Benjamin Thompson

Well, zooming out, Shamini, we know the gender pay gap exists. What are some of the figures more broadly?

Host: Shamini Bundell

Well, yeah, I think it’s hard to deny that the gender pay gap continues to be an issue. There’s obviously always questions about exactly how you measure that and what you’re measuring. So, for example, there was a figure from a few years back from across the US, in all employment, the gender pay gap is around 20%, according to one study. And then in universities, if you’re talking about full professors, 15% in the US and maybe 10% in the UK. And it depends on what jobs people are doing, what education they have, what department they’re in and whether things are balanced within each of these subsections but, of course, the overall inequalities also point to broader societal problems, things like leaky pipelines and lack of women in senior management and the sort of effects that has, as was sort of mentioned in our earlier segment.

Host: Benjamin Thompson

Well, thanks for shining a spotlight on that one, Shamini. For my story today, well, we heard at the top of the show about the diabolical ironclad beetle, and I’ve got a story that was reported in Science about another seemingly indestructible animal – the tardigrade.

Host: Shamini Bundell

That’s our new podcast, the Indestructible Animal Podcast. I’m very here for this. And I love tardigrades. Tardigrades are great. What have they done this time?

Host: Benjamin Thompson

Well, before I tell you what they’ve done, let me just give you some tardigrade facts. They’re little animals, less than a millimetre long, and they can seemingly survive anything you throw at them. You could desiccate them, totally dry them out. Tardigrades don’t care. Put some water on them and off they go again. You can subject them to freezing temperatures, to super-hot temperatures. Tardigrades don’t care. You can expose them to the vacuum of space. Tardigrades don’t care. And adding to that list of extraordinary feats of endurances, another superpower, some of these tardigrades seem very resistant to UV light.

Host: Shamini Bundell

Right, I mean I go out in the sun and there’s UV light so how impressed should I be?

Host: Benjamin Thompson

Well, do you know what, that’s an absolutely fair statement. What I will say is that this isn’t kind of any old UV light because when it’s really, really intense, it can be used to sterilise things. It can be used to kill bacteria and viruses. I myself have used it in the lab to sterilise pieces of equipment, and that’s what we’re talking about in this instance, and some tardigrades have resisted being absolutely battered by this ultra-strong UV light.

Host: Shamini Bundell

Was this discovery accidental or are there scientists out there whose job is to see what tardigrades can survive, like whatever they throw at them?

Host: Benjamin Thompson

Yeah, I think you might be right in this instance, Shamini. Let me explain what happened here then. So, some researchers in India exposed different species of tardigrades to UV light and to a strength that killed bacteria and roundworms after five minutes, so pretty strong. This UV light was lethal to one species of tardigrade after 15 minutes. Pretty good, they’re pretty strong as always. But this one reddish-brown species just survived, like no impact at all, and kept doing so as the researchers upped the strength of the UV.

Host: Shamini Bundell

And is this an evolutionary adaptation that they’ve got?

Host: Benjamin Thompson

Yeah it seems to be. I mean, the researchers involved in this work from the Indian Institute of Science, they reckon that this could be an adaptation to withstand the really high levels of UV that are found in tropical southern India where this species was found, and in fact, it was found on some moss on a concrete wall, which I really, really like.

Host: Shamini Bundell

And how does one actually make oneself more UV resistant?

Host: Benjamin Thompson

Well, in this case, this new species, and it appears to be a new species, has this pigment and this pigment absorbs UV light and turns it into harmless blue light, so that’s what sort of protects them. So, they have this inbuilt UV shield, and when the researchers took this pigment and used it to coat C. elegans worms, these worms themselves survived twice as long under strong UV. It’s such a neat thing.

Host: Shamini Bundell

Oh, that is clever, and sounds like it could be useful for like sun cream, if not many other applications.

Host: Benjamin Thompson

As a very pale man who can get sunburnt at night, I’m very much looking forward to whether that may be the case. But let’s leave the Briefing chat for the time being. Thank you, as always, Shamini. And listeners, if you’d like to know more about both of the stories we discussed, you’ll find links to them in the show notes. And if you want even more stories like this but delivered straight to your inbox, then make sure to sign up for the Nature Briefing and, once again, head over to the show notes where you’ll find a link to do so.

Host: Shamini Bundell

That’s all for this week. But before we go, just time to tell you about an immersive article featuring videos and photos which looks at how farming and food supply in different parts of Africa have been affected by the COVID-19 pandemic. Head over to the show notes for the link. I’m Shamini Bundell.

Host: Benjamin Thompson

And I’m Benjamin Thompson. Thanks for listening.