Quote from: c0rnel on Today at 12:59:49 PMI thought of a few other possible scenarios, some of which might sound crazy.
1) At the beginning of Aliens the marine crew asked if this was going to be another bug hunt. This might imply that they've had an encounter with xenomorph in the past perhaps on a smaller scale. Over time, without their knowledge xenomorph got onboard, hid, and perhaps even laid eggs if a queen was among them somewhere like in the storage area until later when the marines disturbed it by moving cargo around to prepare for the mission in Aliens.
I think it was always intended that the Marines first encountered the xeno in Aliens and Bug Hunt refers to other life forms.
In the much later Free League / Colonial Marines RPG book it is mentioned that in the alien universe there are countless living beings and creatures which the Marines commonly refer to as bugs.