Commercial photocatalyst changes the behavior of Formica pratensis and Formica polyctena

Abstract

Nanosized materials are currently applied nearly everywhere and nanotechnology is part of our everyday lives. For important challenges such as those relating to clean air, water and energy, semiconductive nanoparticles show the most promising solutions. TiO₂ is among those semiconductors which are widely applied and studied in water purification processes by photocatalysis. Despite its abundant applications, its ecotoxicological investigations are relatively rare and none of these address insect behaviour. Therefore, in the present study the impact of a well-known commercial TiO₂ (Evonik Aeroxide P25) on the interspecific behaviour of two territorial ant species (Formica polyctena and Formica pratensis) was investigated. Changes in the behaviour of the ants were observed using aggressivity assays. We found that the results of these tests can be linked to the changes observed in the cuticular hydrocarbon (CHC) profile of the ants, as the applied semiconductor demonstrated its photocatalytic activity and oxidized the hydrocarbons to corresponding alcohols, aldehydes and carboxylic acids, altering the CHC profile, and thus interfering with species recognition. The results are relevant in terms of the potential uses of nanoparticles in more technologies. A significant proportion of these nanoparticles are photoactive materials and can interact with insects using chemical communication channels (e.g. ants and possibly bees).