how to avoid worms crawling up the walls of plates (and dying)?


Im setting up a lifespan assay (im new in this thing) and I noticed that during the first days I loose a considerable amount of my initial population (~50%) because worms crawl up the walls of plates. I can see the dead dessicated bodies on the walls of the plate. I’m using large 90 mm plates with a very low density of worms with plenty of E. coli, so they are obviously not starving. I know this shouldnt be normally a problem, but given the conditions of my experiment and strains I would really like to avoid this issue. Has anyone come with a solution before or have some idea how to solve this? I was thinking of something like adding a thin layer of vaseline with a brush around the perimeter of the plate, since that could maybe stop worm’s curiosity


Hi Jano,

you could try spreading the bacterial lawn a little tighter so that it doesn’t reach the edges of the plate. Or if that doesn’t do the trick, you could add a ring of high molarity sucrose solution around the edge of the plate to produce a barrier that the worms wont cross.


There have been suggestions in a few previous threads: 1, 2, 3, possibly others.

Thanks a lot to both for the advice! The high osmolarity solution sounds good, I will just have to control that it doesnt affect lifespan


ya, i heard about the palmitic acid to form a ring barrier, but i was wondering if palmitic acid in ethanol will have any impact onto lifespan analysis?


Can we add Sodium palmate in dH20 to create the barrier for the worms?

And other question, do we create this barrier after we add the OP50 on the plates? or before? or it doesnt matter?