Green tea and its waste attract workers of formicine ants and kill their workers—implications for pest management

Abstract

Daily, 3 billion cups of tea consumed worldwide and this consumption is accompanied by the discarding of huge waste amounts into the environment. Tea leaf contains a diverse array of toxic molecules. Despite evidence that its waste is almost as rich in toxicants as green leaves; no research has been done to turn this source of pollution into a benefit for ant pest management, where new chemistries are highly needed as a result on insecticide resistance. The present study was performed to explore the behavioral and lethal effects of tea and its leftovers on the black crazy ant (BCA), Paratrechina longicornis Latreille, yellow crazy ant (YCA), Anoplolepis gracilipes Smith, and weaver ant (WA), Oecophylla smaragdina Fabricius. Both fresh tea extract (FTE) and used tea extract (UTE) were detrimental to the survival of BCA, YCA, and WA. FTE was the most toxic solution and BCA was the most vulnerable species. The presence of tea extracts in meals did not prevent workers of all three species from visiting and feeding in the presence their preferred foods. The results presented here suggest that diets containing tea extracts are attractive to BCA, YCA, and WA when in competition with their preferred foods. These extracts were also insecticidal to the worker ants. These properties demonstrate the potential of tea and its waste products for developing novel environmentally friendly and low-cost ant control strategies, which could also be a practical solution to the growing environmental problem it causes.