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| Biologist Nick Bos tells Wikinews about 'self-medicating' ants |
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| Tuesday, September 1, 2015 |
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| Formica fusca, from file. |
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| Image: Mathias Krumbholz. |
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| Nick Bos, of the University of Helsinki, studies 'the amazing adaptations social insects have evolved in order to fight the extreme parasite pressure they experience'. |
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| In a recently-accepted Evolution paper Bos and colleagues describe ants appearing to self-medicate. |
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| 'I have no doubt that as time goes on, there will be more and more cases documented' |
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| The team used Formica fusca, an ant species that can form thousand-strong colonies. |
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| This common black ant eats other insects, and also aphid honeydew. |
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| It often nests in tree stumps or under rocks and foraging workers can sometimes be spotted climbing trees. |
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| Some ants were infected with Beauveria bassiana, a fungus. |
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| Infected ants chose food laced with toxic hydrogen peroxide, whereas healthy ants avoided it. |
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| Hydrogen peroxide reduced infected ant fatalities by 15%, and the ants varied their intake depending upon how high the peroxide concentration was. |
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| In the wild, Formica fusca can encounter similar chemicals in aphids and dead ants. |
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| The Independent reported self-medicating ants a first among insects. |
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| Bos obtained his doctorate from the University of Copenhagen. |
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| He began postdoctoral research at Helsinki in 2012. |
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| He also runs the AntyScience blog. |
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| The blog aims to help address 'a gap between scientists and 'the general public'.' |
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| The name is a pun referencing ants, its primary topic, science, and 'non-scientific' jargon-free communication. |
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| He now discusses his work with Wikinews. |
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| Beauveria bassiana on a cicada in Bolivia. |
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| Image: Danny Newman. |
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| What first attracted you to researching ants? |
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| Me and a studymate were keeping a lot of animals during our studies, from beetles, to butterflies and mantids, to ants. |
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| We had the ants in an observation nest, and I could just look at them for hours, watching them go about. |
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| This was in my third year of Biology study I think. |
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| After a while I needed to start thinking about an internship for my M.Sc. studies, and decided to write a couple of professors. |
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| I ended up going to the Centre for Social Evolution at the University of Copenhagen where I did a project on learning in Ants under supervision of Prof. Patrizia d'Ettorre. |
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| I liked it so much there I ended up doing a PhD and I've been working on social insects ever since. |
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| What methods and equipment were used for this investigation? |
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| This is a fun one. |
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| I try to work on a very low budget, and like to build most of the experimental setups myself (we actually have equipment in the lab nicknamed the 'Nickinator', 'i-Nick' and the 'Nicktendo64'). |
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| There's not that much money in fundamental science at the moment, so I try to cut the costs wherever possible. |
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| We collected wild colonies of Formica fusca by searching through old tree-trunks in old logging sites in southern Finland. |
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| We then housed the ants in nests I made using Y-tong [aerated concrete]. |
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| It's very soft stone that you can easily carve. |
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| We carved out little squares for the ants to live in (covered with old CD covers to prevent them escaping!). |
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| We then drilled a tunnel to a pot (the foraging arena), where the ants got the choice between the food with medicine and the food without. |
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| We infected the ants by preparing a solution of the fungus Beauveria bassiana. |
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| Afterwards, each ant was dipped in the solution for a couple of seconds, dried on a cloth and put in the nest. |
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| After exposing the ants to the fungus, we took pictures of each foraging arena three times per day, and counted how many ants were present on each food-source. |
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| Example of aerated concrete, which provided a home for the subjects. |
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| Image: Marco Bernardini. |
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| This gave us the data that ants choose more medicine after they have been infected. |
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| The result that healthy ants die sooner when ingesting ROS [Reactive Oxygen Species, the group of chemicals that includes hydrogen peroxide] but infected ants die less was obtained in another way (as you have to 'force feed' the ROS, as healthy ants, when given the choice, ignore that food-source.) |
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| For this we basically put colonies on a diet of either food with medicine or without for a while. |
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| And afterwards either infected them or not. |
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| Then for about two weeks we count every day how many ants died. |
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| This gives us the data to do a so-called survival analysis. |
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| We measured the ROS-concentration in the bodies of ants after they ingested the food with the medicine using a spectrophotometer. |
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| By adding certain chemicals, the ROS can be measured using the emission of light of a certain wave-length. |
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| The detrimental effect of ROS on spores was easy to measure. |
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| We mixed different concentrations of ROS with the spores, plated them out on petridishes with an agar-solution where fungus can grow on. |
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| A day after, we counted how many spores were still alive. |
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| How reliable do you consider your results to be? |
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| The results we got are very reliable. |
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| We had a lot of colonies containing a lot of ants, and wherever possible we conducted the experiment blind. |
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| This means the experimenter doesn't know which ants belong to which treatment, so it's impossible to influence the results with 'observer bias'. |
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| However, of course this is proof in just one species. |
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| It is hard to extrapolate to other ants, as different species lead very different lives. |