Lime Butterfly Egg

On the 17th of May I noticed my lime plant being eaten. I found some caterpillars and follow them through their stages until finally they became butterflies. Two of them did not make it into healthy butterflies and the last one ...left an empty cocoon behind and was no where to be seen. Now yesterday I noticed a Lime Butterfly on and around the Lime. "what is it doing here"? No flowers, so no food, I wonder if it is ... and then it landed on a leaf and bend its abdomen quickly under the leaf. I hardly noticed it so fast did that happen and when I looked under the leaf, .. there was an egg! How wonderful! Today I looked again and I spotted three egg in various places. Now does anybody know if this was the mum of the first caterpillars (do they keep coming back to the same mother plant? ) or was my last butterfly a female and is now lying eggs on her birth plant???
See spottings
http://www.projectnoah.org/spottings/326656006
http://www.projectnoah.org/spottings/336926002
http://www.projectnoah.org/spottings/343026003
http://www.projectnoah.org/spottings/370106057
http://www.projectnoah.org/spottings/376106002