Sri Lanka is off to the side of South Asia, Moldova is off to the side of Eastern Europe and Ecuador is small. That's why for the life of me they just didn't come to mind. You attract an interesting crowd, Italy
If you notice, there are a lot of immigrants from the sucontinent (not only Sri Lanka), much more than the other european biggest countries (except UK, of course). It's probably easier to reach/stay or there are some specific productive areas that require people from these countries (like beef farming in Northern Italy: many indians work there).
Moldovan immigration (just like romanian one) is "traditional" in Italy, mostly because of language similarity
Moldovan immigration (just like romanian one) is "traditional" in Italy, mostly because of language similarity