Surfactant affects the tool use behavior of foraging ants

Authors: ZHOU, AIMING - Huazhong Agricultural University; Du, Yuzhe - Cathy; Chen, Jian

Submitted to: Ecotoxicology and Environmental Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2022
Publication Date: 5/5/2022
Citation: Zhou, A., Du, Y., Chen, J. 2022. Surfactant affects the tool use behavior of foraging ants. Ecotoxicology and Environmental Safety. 238:113592. https://doi.org/10.1016/j.ecoenv.2022.113592.
DOI: https://doi.org/10.1016/j.ecoenv.2022.113592

Interpretive Summary: Ants are among few insects that are able to use tools and the most common type of tool use in ants occurs when they are foraging for liquid food, indicating that tool use may play an important role in the development of ant colonies. Surfactants are commonly used in detergents, soaps, and agrichemical products. After use, residual surfactants can be dispersed in different environmental compartments, which can have adversarial effects on various aquatic and terrestrial organisms. On average, ants account for 15–20% of the terrestrial animal biomass and their presence is essential to the well-being of the habitats. How surfactants affect ants? In this study, we hypothesized that surfactant can impact on ant foraging behavior by affecting their tool use behavior. The effect of a common nonionic surfactant, TWEEN 80, on the tool use behavior in the black imported fire ants, Solenopsis richteri Forel was investigated. Natural pine needles and man-made sponges were provided as tools while ants were foraging on liquid food (sugar water). Results showed that ants could use both pine needle and sponge as tools when they were foraging for sugar water. Adding surfactant in the sugar water significantly increased the number of drowned ants and reduced the number of ants involved in foraging, which resulted in less efficient foraging. The results also demonstrated that ants were able to respond to the effect of surfactant by adjusting their tool use strategy, such as increasing the amount of tool used and selecting appropriate sizes of tool, and assembling tools of different structures. These results suggest that surfactant in liquid food can significantly affect the survival and foraging efficiency of ants. Therefore, long-term exposure to surfactant may have a profound effect on ants in the environment.

Technical Abstract: Ants are among few insects that are able to use tools and the most common type of tool use in ants occurs when they are foraging for liquid food. Ant species that use tools may have advantage in their competition with other ants. Surfactants are commonly used in detergents, sops, and agrichemical products. After use, residual surfactants can be dispersed in different environmental compartments, which can have toxic effects on various aquatic and terrestrial organisms. We hypothesized here that surfactant can have adversarial effect on ant foraging behavior. We tested this hypothesis by investigating the effect of TWEEN 80, a common nonionic surfactant, on the tool use behavior in the black imported fire ants, Solenopsis richteri Forel, when they were foraging liquid food (sugar water). Natural pine needles and man-made sponges were used as tools for ants. Results showed that S. richteri could use both pine needle and sponge as tools when they were foraging for sugar water. Adding surfactant in the sugar water significantly increased the number of drowned ants and reduced the number of ants involved in foraging, which resulted in less efficient foraging. The results also demonstrated that ants were able to respond to the effect of surfactant by adjusting their tool use strategy, such as increasing the amount of tool used and selecting appropriate size of tool, and assembling tools of different structures. These results suggest that surfactant in liquid food can affect the survival and foraging efficiency of ants. Therefore, the long-term exposure to surfactant may have a profound effect on ants in the environment.