A novel cage design for investigating tritrophic insect-plant interactions.

摘要

Cages were constructed in 2 components. The lower planter component had a 50x50x21-cm frame of 3.8x3.8-cm pine wood boards with sheets of 0.8-cm plywood fastened to the sides, 50x18 cm, and bottom, 50x50 cm. The upper cage component consisted of a 50x50x50-cm frame of 3.8x3.8-cm boards with 300- micro m mesh nylon screen affixed to the top and 3 sides. The front of the upper component had grooved pieces of pine wood fastened by screws to the frame to serve as a track for a 44.5x44.5-cm pane of 5-mm plexiglass inserted against the frame. The screws allowed the track pieces to be removed as needed to slide out the plexiglass and open the door so that plants could be accessed or insects could be introduced or removed as needed. The lower component had short upright posts in side 2 diagonally opposing corners onto which the upper component fit snugly into place. Four 2-cm-wide holes were drilled in planter bottoms to allow water to escape if overwatering should occur. Pieces of screen were affixed over these holes using silicone and staples to prevent insects from escaping. All wooden portions of the cages were sprayed with spar vanish for a water-resistant-covered cage. The cages were stocked with Delia radicum eggs and Bembidion quadrimaculatum (generalist predator) or Aleochara bilineata (Delia puparia parasitoid). The cages provided an environment where eggs were consumed by beetles in varying quantities according to treatment type, all of the beetles were recovered at the end of the study, plants were vigorous, indicating that the mesh screening, sealing components, draining mechanism of the cages were effective.