As of patch 18.8.29, mantises in Smugglers Den drop their unique loot again. Thanks funcom for fixing this
To get an idea of the drop rate I went on a bit of a killing spree (for science). I’ve killed 200 mantises, which is roughly 2 rounds of all the mid-level mantises in Smugglers Den. The following items dropped for me:
Metallic Mantis armour parts
11 items, 5.5% chance
Deformed Mantidae Abdomen (Ql76) from Den Mantis Digger.
Deformed Mantidae Abdomen (Ql88) from Den Mantis Burrower.
Deformed Mantidae Abdomen (Ql91) from Den Mantis Burrower.
Deformed Mantidae Femur (Ql93) from Den Mantis Runner.
Deformed Mantidae Femur (Ql107) from Den Mantis Worker.
Deformed Mantidae Head (Ql109) from Den Mantis Forager.
Deformed Mantidae Tarsus (Ql88) from Den Mantis Worker.
Deformed Mantidae Tarsus (Ql105) from Den Mantis Scout.
Deformed Mantidae Tibia (Ql110) from Den Mantis Burrower.
Deformed Mantidae Wing (Ql82) from Den Mantis Burrower.
Deformed Mantidae Wing (Ql115) from Den Mantis Runner.
Special profession loot
10 items, 5% chance
Deformed Mantidae Antennae (Ql103) from Den Mantis Runner.
Deformed Mantidae Coxa (Ql95) from Den Mantis Burrower.
Deformed Mantidae Coxa (Ql122) from Den Mantis Scout.
Deformed Mantidae Eye (Ql102) from Den Mantis Forager.
Deformed Mantidae Eye (Ql106) from Den Mantis Earthmelder.
Deformed Mantidae Eye (Ql118) from Den Mantis Burrower.
Deformed Mantidae Mandibles (Ql98) from Den Mantis Burrower.
Deformed Mantidae Mandibles (Ql124) from Den Mantis Forager.
Deformed Mantidae Prothorax (Ql100) from Den Mantis Burrower.
Deformed Mantidae Prothorax (Ql100) from Den Mantis Runner.
Weapons
7 items, 3.5% chance
Splintered Mantis Predator Blade (Ql90) from Den Mantis Drone.
Splintered Mantis Predator Blade (Ql99) from Den Mantis Worker.
Mantis Predator Blade (Ql100) from Den Mantis Burrower.
Metallic Mantis Predator Blade (Ql120) from Den Mantis Runner.
Metallic Mantis Predator Blade (Ql120) from Den Mantis Earthmelder.
Metallic Mantis Predator Blade (Ql120) from Den Mantis Forager.
Metallic Mantis Predator Blade (Ql120) from Den Mantis Worker.