A high-throughput and sensitive method for food preference assays in the argentine ant

Insects pose significant challenges in both pest management and ecological conservation. Often, the most effective strategy is employing toxicant-laced baits, which also must be designed to specifically attract and be preferred by the targeted species for optimal species-specific effectiveness. However, traditional methods for measuring bait preference are either noncomparative, meaning that most animals only ever taste one bait, or suffer from methodological or conceptual limitations. Here we demonstrate the value of direct comparison food preference assays using the invasive and pest ant Linepithema humile (Mayr, 1868) as a model.

We compare the food preference sensitivity of noncomparative (one visit to a food source) and sequential comparative (visiting one type of food then another) assays at detecting low levels of aversive quinine in sucrose solution. We then introduce and test a novel dual-choice feeder method for simultaneous comparative evaluation of bait preferences, testing its effectiveness in discerning between foods with varying quinine or sucrose levels. The nonsequential assay could not detect aversion to 1.25 mm quinine in 1 m sucrose, yet the sequential comparative approach detected aversion to quinine levels as low as 0.94 mm. The novel dual feeder method approach could detect aversion to quinine levels as low as 0.31 mm, and also preference for 1 m sucrose over 0.75 m sucrose.

The dual-feeder method combines the sensitivity of comparative evaluation with high throughput, ease of use and avoidance of interpretational issues. This innovative approach offers a promising tool for rapid and sensitive testing of bait solutions, contributing to the development of targeted control strategies. The method also could be easily extended to other ant species. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.