Posts Tagged ‘biological invasions’

yes, better than Starwars and World of Warcraft together, the wars of ants. Last year in our lab, we set up wars between different species, among the most aggressive in the world.

I’m sure you can imagine. Monstrous armies of millions of Unsullied warriors, impervious to danger, dedicated to the death, working together with the efficacy given by millions of years of evolution, all entirely bent to one single purpose, destroying the other armies. I’m certain to are picturing this. Well, you are picturing it wrong, you immature brutes. So, what did we do and why did we do it?

It was a time when a Ph D student (Cleo Bertelsmeier) was studying the effect of climate change on invasive ants. I’ve told you already why we study invasive ants. If you’ve missed it, you can read it here. The first part of the PhD thesis was to build up species distribution models to try and predict where invasive ants would find favorable regions with climate change (ants are very sensitive to climate, and milder winters may mean higher probability of establishment). And the result was that some of the most problematic invasive ant species were predicted to arrive at the same place in several regions. And because the most obvious characteristics of all these invasive ants is that they are extremely efficient at removing other arthropods, starting with local ant species, we naturally wondered what would happen if two of such Hun armies were to clash in newly invaded territories. Or in other words, is there among these tiny berserk beasts one that would take over all the others (and the rest of the world with it).

So we set up colonies of four of the worst of the worst. These were the invasive garden ant Lasius neglectus, the Argentine ant Linepithema humile, the big-headed ant Pheidole megacephala and the electric ant Wasmannia auropunctata. The experiment set up by Cleo was not really the wars you pictured, but they were enough for our purposes: boxes with colonies of 300 workers and one queen, put into contact by a tiny tube, and days of counting the dead and the survivors. And these taught us a lot. First, that the experiments of one worker versus another in a Petri dish – often set up to establish dominance hierarchies among ant species – are not well suited, because some ants species need other workers to kill others. Some ants hold the enemy while it is being cut into pieces, and you can’t do that when you’re alone, and you’ll systematically lose in duels but not necessarily a battle. It also mean that classical experiments of 10 vs 10 workers in a Petri dish are also problematic, because the lack of natural conditions can bias the results. These ants are very stressed, more or less forced to fight, and with no territory, nest or queen to defend (which was not the case in our experiment). Last, it taught us that ants adapt their strategies according to their opponents. Some species that are very aggressive and kill everything were less so when confronted to potentially stronger adversaries. Some even escaped or feigned death. And some raided the other colonies D-Day style improved with chemical weaponry, with many losses but an eventual conquest while some others remained in their strongholds and privileged defense. And eventually it taught us that when you increase complexity, for example by putting all four species together, you increase… well complexity. Here, the species that systematically lost against any of the three others won half the time when all four were fighting simultaneously.

Now I’m sure you’d like to know who was the meanest of the four. The tiny electric ant, so named for its terribly painful sting? Or the scary big-headed ants, which soldiers can cut in two any of the other species? Well, I guess that to know that you’ll have to read the paper (and perhaps that one too about their strategies)… Yes, I know, I’m mean. That’s what the ants say too.


Of course, the best fighter of all remains the Ant-man



Just a short note to inform you of the results of the BNP Paribas public vote: we won!
for those of you who followed the unbearable suspens of this sage, here are the figures:
FATES = 329
SOCLIM = 597
APT = 3361

So thank to you (yes, you), our research group is awarded an additional 50.000€ for communication purposes. We will use this money in two major ways. We will first buy the design and construction of an interactive web site to explain our results to the public, and allow them (yes, you again) to check that we are not just playing angrybirds all day long, ask questions and request all the analyses they want. We will also use this money to hire a communication officer that will be in charge of this web site, of dealing with emails from the public (i.e. replying to insulting ones and forwarding me the nice ones), of writting media memos and of many other things that we scientists are too clumsy to do ourselves.
Anyways, this is an opportunity to once more thank you all for your votes!
From the hysteria in France and the US to the delirium in Indonesia and Brazil and the frenzy in Australia and China, we now know we can count on hordes of devoted followers, ready to the craziest things for us, even sometimes read this blog.



The Fundation BNP Parisbas selected 5 scientific programmes on climate change and will give 50 000 € (that’s US$ 62,000) to one selected by the public, for a communication project on their scientific programme. This is why we need you to vote for our project: InvaCost.

InvaCost will look at the impact on invasive insects, when climate change allows them to invade regions that are now too cold for them, but that will warm up in the coming decades. These include the red imported fire ant, the predatory Asian wasp, the disease carrying tiger-mosquito, and many others that are among the worst invaders worldwide. InvaCost is described a bit in an earlier post, here.

Our communication project is really different from anything that has been done before, and very probably different from the four other projects. In addition to building an interactive website to communicate with the public, show and explain our results and answer your questions, we will inaugurate a new type of citizen science, or participatory science: the public will be able to select some of the 20 invasive species we will study in InvaCost, from a large list we will compile. You will also be able to ask us to do specific analyses, for example “will Argentine ants be able to invade the UK?” or “where will the Formosan termite invasion expand in the USA” or “Is the malaria mosquito likely to reach my city and when?”. We will then collect the data, build and run the mathematical models, analyse the outputs and show and explain the results.

In a word, you will chose the subject and the questions, and we will do science for you. The money will be used to design and run the web site and to hire staff to interact with the public and make specific analyses during the four years of InvaCost. The communication project is described here.

So if you want to see that happen, it’s quite simple, vote for our project, by going here. And forward the message around, we will likely need tens of thousands of votes to be selected. Thanks in advance, we look forward to working with you!


I’m normally not a big fan of citizen sciences. Because as trained scientists we strive so carefully to achieve the upmost rigour, I always have this irrational uneasiness when it comes to handling data that have been collected by thousands of uncontrolled volunteers, good-willing but sometimes scientifically unqualified. Citizen science is a great idea though. In a nutshell, it is the fact of using the network of citizen to gather simple raw data and send them to a centralizing team that will assemble it into a giga-dataset that we scientists, with our slow performing slaves, sorry students, cannot even dream of achieving on our own. That way, we can learn about the changes in arrival dates of migrating birds all over Europe, we can more quickly identify star clusters and exoplanets, or reconstruct past climates from thousands of log books of old ships.

So citizen sciences means science made from data collected by citizen. It is nice because it gives enormous datasets to scientists, but also a nice feedback to citizen: in general those implied are interested in birds, or stars, or ships, and are happy to be involved in projects and know the results on programmes in which they have contributed.

It’s a win-win situation, but I thought there could be more to gain for the citizen. This is why, in the days to come, our group – Biodiversity Dynamics – will present a new project in which citizen can do more than collect data and find out the results. Way more.

We have been awarded a grant from the Fondation BNP-Paribas to study the effects of climate change on invasive insects. If you want to know more about why insects could very well invade our regions in the near future and how this is going to be bugging, read this post. If you want to know more about which species are likely to invade where, and when, than this is for you: we will propose in this project to involve citizen in a way they have never been so far. Citizen will not collect the data here, they will instead play (some of) the scientist role: they will ask questions. That’s right. You will start by choosing (some of) the insect species that we will work on. We will propose a list of interesting cases and you will be able to select one from them. We will set up an interactive website to post our results such as distribution maps and graphs and you will also be able to ask for more (e.g., “would it be possible to model the potential distribution of invasive fire ants in England in 2050?”). If the requests are reasonable and within our reach, we will do it and post the results (with the explanations). If they are not, we will explain why (so that you can stop taking us for scientists from the TV shows and ask us irrealistic things).

There is a catch though. This “novel citizen science” project will exist only if we win the vote of the public, which will select one project over 6. I will post soon the vote links so that you can unleash the mad clicking-beast that hides in you and thus allow us to serve you better. For, always remember that, as scientists, our ultimate goal is serving Humanity.


Of course Gibbs, every scientist is like me: an expert in all possible fields that will give you awesome results within the hour

I have been working for years on biological invasions. You know, the species that are put into regions in which they don’t belong and that just expend madly and outcompete everything, unchecked. A bit like Mcdonald’s in France. Because I’ve also started working on the impact of climate change on biodiversity, I’ve naturally wondered (like many) whether climate change would affect biological invasions.

My group – Biodiversity Dynamics – has produced already some awesome work on that. For example, see here, here or here. Or here and here. Or here. Ok, I stop. You see, they produce too much, I’m not the only one to say that.

Anyways, because climate change is likely to make winters milder and habitats climatically more suitable year-round for cold-blooded animals like insects, we have been wondering whether invasive insects would be able to invade other regions with climate change. There are many very nasty bugs out there.

For example, the Asian predatory wasp is an invasive hornet in Europe that butchers pollinating insects, especially bees, thereby affecting the production of many wild and cultivated plants. And we all remember what Einstein said about pollinators: « if bees were to disappear, humans will disappear within a few years » (we all remember that because it’s one of the few things he said that we understood). The highly invasive red imported fire ant is feared for its impacts on biodiversity, agriculture and cattle breeding, and the thousands of anaphylactic shocks inflicted to people by painful stings every year (with hundreds of deaths). Between the USA and Australia, over US$10 billion are spent yearly on the control of this insect alone. The tiger mosquitoes are vectors of pathogens that cause dengue fever, of the chikungunya virus and of about 30 other viruses. And I could go on.

Most of these nasty creatures are now unable to colonize northern regions of Europe or America, or southern regions of Australia, for example, because they cannot survive cold temperatures. But how will this change? Where and when which species will invade with rising temperatures? What will be the costs in terms of species loss? In terms of agricultural or forestry loss? In terms of diseases to cattle, domestic animals and humans? What will be the death toll if insects that are vectors of malaria can establish in new, highly populated areas?

All these questions, we’ve proposed to study them from a list of 20 of the worst invasive insect species worldwide. And we got selected (ie financed), so brace yourself, we are going to provide some answers. Soon. I just need to hire a couple of postdocs first to do all the work for me.


I don’t care; I don’t like popcorn anyway


When I was young – yes, that was indeed last century – I made a paper with two American scientists that I had never met. I one them I met years after, on the other side of the world (for me), in New Zealand. The guy is quite fascinating for a number of reasons, one of which being that he has wild ideas, the type that divides the world into those that will call him a genius and those that will loath him, ever after. That’s Josh Donlan. A few years back, he published a paper in Nature that created some waves in the normally well-behaving community of conservation biologists, about assisted colonization: rewilding North America.

The idea is that the Pleistocene is not so far away, in eco-evolutionary times, and that a few thousands years ago, the great mammalian megafauna was still roaming the plains where Clint Eastwood rode yesterday. So in terms of ecology, there are a bunch of key ecological processes that are not performed by these beasts anymore. Also, there exist large animals in the world now that could somehow replace their extinct ancestors: elephants, camels, lions, horses, giant tortoises… Wait, it gets even better: many of these species are currently endangered in their native areas, so translocating them into North America could also alleviate some of the threats they face in Africa and Asia, such as poaching. Just think about some critically endangered Equidae, like the Przewalski’s horse. Or like the wild Asian ass. I’d put you an image of this magnificent animal, but I seem to have problem with my browser; it behaves strangely.

Brilliant idea, but… There are a number of problems as well. Let’s put aside the fact that it is very costly, long and probably logistically nightmarish to obtain a large population of a large mammal from another continent. Remains two drawbacks as big as that mega-fauna. First, there are important conflicts with humans and some of these animals, in particular elephants and lions. Human-animal conflicts are so problematic that entire sessions are devoted to them in conservation meetings. Second, putting species where they don’t belong ecologically often leads to biological invasions, something that can be very nasty. Ask the Australians about the half-million feral horses and twice that many camels that roam in their backyard.

So on one hand, we have a superb solution to save some endangered species with a really bleak future, and in the meantime restore the ecological functioning of the great plains of late (while providing some amazing sights that will undoubtedly increase the ecotourism value of the Giant Sequoia National Park); and on the other one, we have a potentially evil danger of novel human-animal conflicts doubled with uncontrollable alien invasive species. A perfect debate menu for our Semibière meetings (see the previous post on that).

So, what about you, my friend. You’d be against, or for it?



Yes, I mentioned that earlier: we study invasive ants. We do all kind of fun things we them, from models trying to predict where they could be invasive, now or with climate change, to lab experiment trying to see which species are better at finding and monopolising resources. There are a bunch of papers now that we have published on that (and more to come, that I will probably advertise here, so I won’t say too much now), but the point is, they are very interesting, and quite problematic for biodiversity and economics alike.

There are about 20 000 ants species out there (40% of which remaining to be described by science). One percent of these species are exotic, meaning they have been introduced outside their native range, and seem to have been established there. About a tenth of these 200 exotic species are known to be highly invasive. That mean they are mean. And I do mean mean. Not the mean mean, really mean. Ok, I stop. They are highly aggressive and exceedingly efficient. When they invade, they destroy the native entomofauna, starting by the native ant communities, but also affecting plants, other invertebrates, amphibians, reptiles, birds and even mammals. Humans are known to be victims of the Red Imported Fire Ant by the thousands in the USA (with hundreds of death – that is more than by sharks). They really affect biodiversity and doing so they disrupt ecosystem functioning and services (like pollination and seed dispersal). And they cause billions of dollars of damage every year to agriculture, forestry, real estate and public health.

Oh, and they also go by scary names, like the fire ant, the electric ant, the crazy ant, the destroyer ant, the ghost ant… And before you ask, yes there are zombie ants and vampire ants as well, only they are not invasive ants. No werewolf ant though. Kinda disappointing.

Anyway, invasive ants are about to take over the planet, and who is working their ass off trying to save the day, in the general ingratitude? To whom will you turn when they try and make you their slave? Biodiversity Dynamics, thank you.

So, to answer the question in the title, we study invasive ants, simply because invasive ants are importants. Import-ants. Get it? Ok ok, I thought that was a good one…