In an open topped, stackable, molded plastic container (1), which is generally rectangular with a bottom (2) and first and second pairs of parallel upright walls (3, 4, 5, 6) joined to the bottom and at corners via corner structures (10). Each corner structure comprises a hollow tubular post (13) with a lower protruding stacking pin portion (13p) such that - in a stack - the pin portion of an upper container is received through a hole (14) in a top wall (12) of the corner structure of a lower container onto which said upper container is stacked. Multiple vertical stacking ribs (15a-g) are arranged circumferentially spaced about the hollow tubular post (13). The container is used in combination with a spawn structure in which the mother insects will spawn their eggs. The spawn structure comprises a foldable member and a rigid member.
