The tropics of Glasgow: Working in an insectary
Dr Emilie Pondeville, Research Associate at the MRC-University of Glasgow Centre for Virus Research, works with one of the world’s most renowned tropical insects – the mosquito. To mark World Mosquito Day on 20 August, she describes what it’s like to work in an insectary and explains the importance of research in mosquitoes.
Like many people, I don’t really like insects. But mosquitoes are different.
I work with Aedes aegypti mosquitoes, known for transmitting diseases such as Zika, chikungunya and dengue fever. Not every species needs a blood meal to reproduce. But the ones we rear are anautogenous, meaning they must feed to mature their eggs.
Mosquitoes bite infected people and ingest the virus. The virus replicates and travels through the midgut to the salivary glands. Female mosquitoes then retransmit the virus with each feed – they can bite many times throughout their lives.
The secret to beautiful science
Mosquitoes are used to living in warm and humid climates. For optimum growth and breeding we try to mimic their natural environment in the lab. This essentially means that my ‘office’ is a sweltering 28°C (82 °F) with 70-80% humidity. I think it’s great to have the hot insectary here in Glasgow because it can get quite cold outside!
The natural habitat of larvae – the first stage in the mosquito life-cycle – is mostly water. In the lab, we put the egg-laying paper into a pan of 1-2cm of water. The eggs hatch a few hours later and give rise to the larvae.
The larval stage lasts about eight to ten days, then they become pupae, ready for metamorphosis. The adult mosquitos form, pierce through the pupa skin, dry their wings for a few minutes and then lift off.
Good rearing of mosquitoes is important because we rely on them for our experiments. If you have bad mosquitoes you’ll do bad science, but with good mosquitoes you’ll do beautiful science.
The biology of mosquitoes is an important factor in virus transmission. I dissect their tissues to look at what’s going on in their bodies and to understand how they transmit the virus. It’s a fiddly job so I need to be careful not to drink too much coffee when I want to dissect mosquitoes.
Within the A. aegypti species there are different genetic strains that have been collected from all over the world. For instance, we have a strain which was collected in Tahiti and another called the Liverpool strain, collected by people working in Liverpool. The Liverpool strain has been maintained in labs for over 80 years and is the only one whose genome is sequenced.
Researchers are working to understand why some strains transmit viruses and others don’t. Just imagine if we found a species that couldn’t transmit. If we can identify why one strain cannot transmit a virus, and find a gene involved in that process, we could try to insert, or modify, the gene of a susceptible strain to make it resistant.
Using this process, called genetic transformation, I can potentially alter their genome – like a magician transforming a bad mosquito into a good one.
When it comes to mosquitoes, many people say “they’re annoying…”, but they just want to live. Their first goal is not to transmit pathogens or to scratch you. They just want to reproduce, like every other organism on earth.
Find out more about research carried out at the MRC-University of Glasgow Centre for Virus Research.