Teflon

All chemicals were commercial and used as received. Zeolites (3A, 4A and 5A) from BDH—Laboratory Reagent, sulfuric acid 96%, acetic acid glacial, low molecular weight chitosan, sodium sulphide nonahydrate ≥ 99.99%, and Teflon (poly(tetrafluoroethylene)) particle size 35 μm from Sigma-Aldrich, a mixture of industrial crude glycerin (82% glycerol, from a Portuguese company) and 5,5′-Dithiobis(2-nitrobenzoic Acid) > 98% from TCI.
The HeLa (human cervical cancer cell line) cells for the cytotoxicity studies were from the American Type Culture Collection, Manassas, VA, USA. The medium RPMI-1640 without L-glutamine from Corning Inc. Penicillin-streptomycin, L-glutamine, foetal bovine serum (FBS), trypsin (2.5%, without phenol red), were from Thermo Fisher Scientific (Manassas, VA, USA).

Each potted cotton plant was held in a plastic tray (42 × 26 × 18 cm) and covered with nylon netting surrounded by a wooden cage (90 × 90 × 100 cm). The potted plants were randomly arranged. Thirty 2nd instar mealybugs were transferred to each caged plant. The ant colony fragment was placed into a small plastic container (22 × 15 × 7 cm), and connected with the plant tray by a silicone tube (0.8 cm in diameter and 10 cm in length) (Figure S1). To prevent the ants from escape, Teflon (Sigma Aldrich, Shanghai, China) was applied halfway up the inner surface of each ant colony container and plant tray. This treatment design allowed ant workers to approach the mealybug colonies directly through the plant trunk. After 24 h, two lady beetle larvae were introduced on the plants as predators. The ant colony was provided with 50 mL of water every 2 days. A completely randomized design was conducted for this experiment, including T. melanocephalum, P. longicornis, T. bicarinatum, a combination of T. melanocephalum and P. longicornis colonies, and a combination of T. melanocephalum and T. bicarinatum colonies. No ant tending was used as a control. Each treatment was replicated 12 times, and the number of live mealybugs per plant was recorded after six weeks. The colony growth rate of mealybugs was defined as the final population density divided by the initial population density.