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Curator of Diptera's blog

4 Posts tagged with the dna tag
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So it is that time of year again when we head out on fieldwork - looking for flies up and down the country, in bogs, and woodlands, and wet meadows trying to seek out the often elusive individuals. For the last couple of years, the Natural History Museum has been working in collaboration with the Health Protection Authority on a specific project collecting mosquitoes and we are finding all sorts of interesting things. New records for species distributions have been determined and thanks to some molecular anaylses we are figuring out some difficult taxonomic questions.

 

So off we head, boots on, silly fieldwork appartus strapped to our backs (or rather just back as only one was used). However, as well as the working with mosquito adults for both morphological and molecular analyses, we are also going out to look for the larvae.

 

Mosquito larvae are cute, and active, and fast…We use a very hi-tech piece of equipment to catch the little blitters (a plastic pan on a long pole…..) and then dip away in favourable habitats

 

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Above is Shelley supporting the oh so fashionable Backpack aspirator whilst I am modelly the latest in dipping technology...

 

We were back in Hurcott Wood (it was a little warmer since the last time I was there recording for the BBC) after a very successful trip there last year. Alex Vaux, from HPA joined us (i.e. Shelley Cook, Ralph Harbach and I) and we pottered (or in some cases pootered albeit on a large scale with the back pack aspirator) round trying to catch the early adults or the larvae.

 

We couldn’t find any adults but we did get some larvae and some big ones at that! These were ferried back to London in little plastic packs alongside some spare pond water.  Once back in the museum we set up the little ones in a basement lab through very secure doors which makes the place feel more like a maximum security prison than research labs

 

They are set up initially in bowls but as they develop they get their individual rearing tubes - nothing but the best for them. We do this as we need to collect their larval and pupal skins as they develop. For mosquito taxonomy we use the 4th Instar stage of the larva, the pupal skin and the adult.

 

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The 'rearing lab'

 

The mosquitoes are separated into two subfamilies, the Anophelines and the Culicines. The Anophelines lie flat under the surface to the water and generally feed from there whilst the Culicines have a long funnel through which they obtain air and dangle down into the water column (see below). For them we place the food on the bottom. The special diet upon which they feed is fish food – but you have to get the fine stuff otherwise it is too large for their mouths

 

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Look at the little cuties dangling down...

 

There are four of us in the museum checking up on them, we even have a doodle calendar to make sure that they don’t get forgotten due to our hectic lives . Gradually we are rearing them through although it has not been plain sailing, nope; there has been heartache as well as joy.

 

A lot of the larger individuals, which we think were Culiseta (they were big – almost 6mm!!!!) died straight away – not a good start. Then some of the larvae died when they were transferred to their individual tubes – again not good. Some of them died whilst they were emerging from their pupal case – that was probably the saddest – all that struggle and then trapped, not good.

 

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They nearly made it....

 

But luckily some made it (although we then killed them). But they did get to live for 24 hours first as we had to wait for their genitalia to rotate……

 

And here are some of the successful adults, with their legs in the air like they just don't care!!!

 

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So for these we have larval skins, pupal skins and the pinned adults. This is important as there are many species groups in mosquito taxonomy so by studying all the different stages as well as sequencing their DNA we can hopefully begin to unravel some of these mysteries. And it is one of the few times that I get to feel maternal….

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Half term

Posted by Erica McAlister Feb 16, 2010

It's busy out there, very busy! It does not help that it is raining. But it is also very busy in here! At the moment I have two work experience students working in one of the cocoon ends sorting some British material and hopefully extracting localities data to be used for UK recording schemes. Two of our regular visitors have just turned up and they are straight away into recurating their group that they are working on (Agromyzidae). And I am about to spend the afternoon identifying British mosquitoes. We have to quickly identify the mosquitoes that we sampled last year that have been in the deep freeze ever since. This will involve us identifying them on blocks of dry ice or freezer blocks to ensure that there is no degradation of any virus DNA that the mosquitoes may have. I believe that we are going to have cold fingers

 

There was a meeting here last week for European Mycetophilidae several  workers. It is always nice to meet the people whom you have been corresponding with for a while and read their papers. Its a good opportunity to swap material and receive back material. One of them has donated some fungus gnats from Japan and I have spent the whole morning so far trying to enter all of the new data onto our database. I have only entered four of the 13!! oh well. The database is a vast and complex interactive entity (it is living!!) which is full of oddities that were migrated across when we finally combined all of the many different museum databases. This means though that we are cleaning constantly and so even the small entries may take time due to all of the different modules (i.e. the taxonomy, the collection event, the site where collected) that need to be edited. When you look at the online database you will find many mistakes- we are trying to clean but we have millions of entries .

 

We had another Dinosnores at the weekend and I think that it went well. It was very different this time as I was by myself and I had no one else to abuse on stage! I don't think that the first talk was as good but i loved the next two. The kids were really quite knowledgeable and this always helps. We had some live stick insects this times as well, the Anisomorpha, which exude and sometimes squirt a nasty toxin. They didn't do anything this time though... The male was attached to the adolescent female waiting for her to mature - a strategy that I am glad that most humans don't employ.....

 

And I am doing a Nature live tomorrow on my favourite insect (fly ) I have a soft spot for the robber flies but I keep getting sidetracked. I will get out some of the new material from French Guiana as i think that people will be amazed at how much variety there is in a sample.

 

Oh and I have a very large number of volunteers for my new material .

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Us and Them

Posted by Erica McAlister Dec 30, 2009

I have titled this blog so as at the moment it really does feel like it! There are virtually no science staff (most are on holiday) but 5 million visitors!! The Museum is exceptionally busy at the moment and the fact that it has not stopped raining has compounded the problem!! The public are queuing around the ice rink!! Just getting through the public galleries is an ordeal!! I feel nicely tucked away in my bay just listening to the few other entomologists typing away . I have been reading papers on the use of museum specimens for DNA analyses and am now itching to get back into the lab and have another go at extracting. We are working on some UK mosquitoes at the moment that were collected from our various fieldtrips this year that have been stored in the freezer to prevent the DNA degrading.


I have spent the morning in the Specimen Preparation area in the Cocoon. I have been waiting to properly get my hands dirty with the material that came from French Guyana and so though that this would be the perfect opportunity. For some reason there are an awful lot of horse flies. Several of us have commented on this fact that when using malaise traps (tent like trap for catching small flying insects) there is always an abundance of them. The speaker system was not working though and I spent a long time scribbling down things for the public. These samples have an abundance of dung beetles, cockroaches, hymenoptera of all sorts, bark beetles and of course my babies! As well as all of the horse flies (and some long tongued ones!) and the robberflies there are also some very pretty soldier flies . I cant decide which is better - knowing that there is loads of new, undescribed species or being able to say what is in there already. It's all terribly exciting - I will calm down soon!

 

I was trying to write down little facts for the public as I sorted. I am not sure that they were happy about some of them. There are the Phorid flies of which some burrow down into coffins whilst others decapitate ants! Then there were the assassin bugs of which some are blood feeders on us! There are the dung beetles where i described my fieldwork of collecting them using various different types of dung....

 

...I will have to change the alcohol that the sample arrived in though as after two hours i was a little bit vacant to say the least!

 

This afternoon i am writing a case study for sampling insects in Costa Rica for a book to be published later on in the year. I have written a draft already but it needs to be more concise. I see an afternoon of red pen!

 

I am preparing myself for the sleepover as well. I have been revising my knowledge of all arthropods that can harm, maim, cause death etc. I will be such a hit at the New Years Eve party I am going to!

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Fieldwork on the farm

Posted by Erica McAlister Aug 3, 2009

Afternoon,

 

We had the most exciting fieldwork on Friday.  The first part of the day was spent on an Urban Farm. There were four girls (including me) and a French man carrying out this particular fieldwork and therefore lots of cooing over the animals. We were looking for mosquitoes and were armed with two backpack aspirators, a hand aspirator and a sweep net.

 

To be truthful, we were not expecting much as sampling can be very hit and miss (that will amaze people who are always being bitten!) but we were most surprised as we sucked up hundreds of specimens (now sitting in a minus 80 oC freezer awaiting DNA/RNA procedures). We also got nibbled by alpacas, screamed at by sheep and gobbled at by a ridiculous turkey – i just don’t understand those animals at all….

 

We then went onto Richmond Park to see if there were any resting adult populations that we could find there. We knew that this would be hard and we did not come across any. However we were also sampling for flies in general and so the afternoon was not altogether a right off (there were ice creams too :) ) It is lovely to get back into the field collecting.

 

The photos are from the farm and show some of the treacherous conditions that we have to sample in…



Erica McAlister

Erica McAlister

Member since: Sep 3, 2009

I'm Erica McAlister, Curator of Diptera in the Entomology Department. My role involves working in the collection (I have about 30000 species to look after and over a million specimens), sometimes in the lab, and thankfully sometimes in the field.

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