It seemed as though the mantid had been producing the corrupted amber for some time before our... intervention. It stands to reason that they are keeping a stockpile of it somewhere.
The Shado-Pan's scouts have been reporting an increased presence of the swarm's warriors in Klaxxi'vess. I would wager that they are guarding the corrupted amber.
Meet me there. If we have a chance to destroy that amber, then we need to take it.