Ants avoid food contaminated with micro- and nanoplastics

Area of Science:

• Environmental Science
• Ecotoxicology
• Terrestrial Ecology

Background:

• Micro- and nanoplastics (MNP) are prevalent pollutants in aquatic ecosystems, with less understood impacts on terrestrial environments.
• Insects, such as ants, serve as valuable bioindicators for environmental pollutants due to their ecological roles.

Purpose of the Study:

• To investigate the capability of the acrobat ant, Crematogaster scutellaris, to detect and avoid micro- and nanoplastics in their food.
• To assess the potential for micro- and nanoplastic accumulation in ants following exposure.

Main Methods:

• Ants were presented with a choice between uncontaminated and polyethylene-treated food solutions.
• Feeding preferences were recorded over 20 minutes.
• Fluorescent micro- and nanoplastics (fMNP) were used to observe accumulation in ant mouthparts via fluorescent light microscopy.

Main Results:

• Crematogaster scutellaris workers demonstrated an ability to detect and avoid MNP-contaminated food, preferring uncontaminated solutions for the first 10 minutes.
• This preference diminished after 10 minutes, potentially due to feeding satiation.
• Visible aggregations of fMNP were observed in ant mouthparts after 10 minutes of exposure.

Conclusions:

• Ants possess a degree of MNP detection and avoidance capability, but this may be overcome by satiation.
• Micro- and nanoplastics can accumulate in ants, indicating a potential pathway for terrestrial trophic transfer.
• Further research is required to elucidate MNP detection mechanisms, accumulation dynamics, and colony-level impacts.