Hello Xinmi,

When we perform RNA extractions from mosquitoes, we first homogenize them in "mosquito diluent", this solution allows for both virus isolation and RNA extraction. It keeps viruses and RNA stable.

If you are not looking for RNA viruses, could you store the insects directly in Trizol reagent? This would keep your RNA stable, and samples would be ready for RNA extraction in the laboratory. I would include a metal BB in each tube when you aliquot it, so you can homogenize the insects easily (if using a mixer mill). Of course, you would be limited to performing a trizol extraction. Shaking the tube with the BB included should saturate your sample with the reagent of your choice.

mosquito diluent:

1X PBS with 20% heat-inactivated FBS, 50 ug/mL penicillin/streptomycin, 50 u/mL gentamycin, 2.5 ug/mL amphotericin B

Dear Dr Zhang,

I personally prefer carrying a stereo-zoom microscope in the field. It is better to do preliminary identification of the collected specimen, after you have reached your field camp, if such arrangement is possible. After this you can preserve your specimen in the preservative of your choice. We use RNAlater and have good results with RNA. We had problem in nucleic acid extraction with samples preserved in alcohol. Alternative to this, you can sort the specimen, followed by preserving majority of them after keeping a few for identification at a later stage. For this you have to carry a cool container. In our experience, certain small insects (mosquitoes, ticks etc.) can be kept (in secure containers) and transported (dead or alive) in room temperature for a couple of days without any visible degradation of the morphology. These can then be used for identification after reaching your mother lab.

Yes, it is difficult to get the specimen submerged in the RNAlater. We usually take sufficient solution in 15 ml centrifuge tubes, then put the specimen in it and then insert a cotton plug, which pushes the specimen deep into the solution. You can collect specimen again by taking out the cotton plug, whenever you need.

Hope this works with you,

best wishes,

SD

Hi Daniel,

Thank you for the suggestion! However, I will have more than 24h in the field before I can take all the insects back to the lab.

Now I got two ways to do: 1) the first is to keep the insects alive until I take them back to the lab, but then I need to kill them for identification. After ID I could homogenize them as your suggestion for storage, but I have no idea where should I ID them in: enthonal or other solution to prevent RNA been degrading.

2)the second one is to collect the insect directly into some solution that can protect the RNA. In this case, I first thought of RNAlater or DI water with detergent. But I am not sure which way is the best, or if there are any other suggestions.

You can also preserve specimen in TRI reagent or TRIzol, for RNA purification, as Daniel has mentioned. However, you have to be extra careful with this reagent since it is phenol based and is hazardous. You have to ensure that containers carrying this chemical are leak-proof.