Lasius Flavus are fully claustral, which means that the queen can survive the full time taken from laying eggs up to the arrival of the first worker without feeding, so, in theory, there is no need to feed.
In this case, it is more difficult, the queen arrived by post 50 days ago. Although she came with a small amount of brood, at the time there was water in the tube and I noted that they may have drowned. Anyway, I stuck with it but there was no obvious sign of any development and the queen lost interest in them.
Over this interim period, the test tube started to dry out so I offered a replacement which the queen would not move into but after 50 days she has done so I disconnected the old tube and examined it thoroughly, there is nothing alive in there.
So, what should I do now, can she survive long enough to try again, personally I doubt it, but I can see no clear guidance anywhere on the Internet. I decided to offer a drop of nectar on a small piece of plastic as a starting point and immediately she started to get quite lively and interested so I covered her up to leave her to it. my intention is to leave her overnight to see if the queen's gaster (the lump on the end) expands as this would indicate that she has been feeding, if so the next step will be some protein.
I'm still hopeful this queen can have her strength built up to have a second go at starting a colony assuming that she is not infertile. I will report back if anything significant happens although it may be several months. In the meantime, you can follow my ant-keeping adventures on my main site.
A quick update, I did feed her some nectar, I was planning to offer some protein the following day but before I could do so she produced a batch of brood so it is now a case of waiting 8 or 9 weeks to see where we get to