Get Rolanberries to spawn Guardian Crawlers on Map 1 by trading it to the basket in the room with the lizards, it's a 30% spawn rate.
Afterward, take the resulting item to the second map to one of the baskets at H/G-7 (not the southeastern one in H/J-8.) Trade it to them for a 50% chance to spawn a Drone Crawler, which will drop this item.