Impact of ecological doses of the most widespread phthalate on a terrestrial species, the ant Lasius niger.
Phthalates are synthetic contaminants released into the environment notably by plastic waste. Semi-volatile, they adsorb to atmospheric particles and get distributed in all ecosystems. Effects of this major anthropogenic pollution in economical species in aquatic habitats have attracted large interest. On the contrary, very few studies have focused on wild terrestrial species. Yet, these lipophilic molecules are easily trapped by insect cuticle; ants and other insects have been shown to permanently bear among their cuticular components a non-negligible proportion of phthalates, meaning that they suffer from chronic exposure to these pollutants. Oral route could also be an additional way of contamination, as phthalates tend to stick to any organic particle. We show here via a food choice experiment that Lasius niger workers can detect, and avoid feeding on, food contaminated with DEHP (DiEthyl Hexyl Phthalate), the most widespread phthalate found in nature. This suggests that the main source of contamination for ants is atmosphere and that doses measured on the cuticle correspond to the chronic exposure levels for these animals. Such an ecologically relevant dose of DEHP was used to contaminate ants in lab and to investigate their physiological impact. Over a chronic exposure (1 dose per week for 5 weeks), the egg-laying rate of queens was significantly reduced lending credence to endocrine disruptive properties of such a pollutant, as also described for aquatic invertebrates. On the contrary, short term exposure (24h) to a single dose of DEHP does not induce oxidative stress in ant workers as expected, but leads to activation of the immune system. Because of their very large distribution, their presence in virtually all terrestrial ecosystems and their representation at all trophic levels, ants could be useful indicators of contamination by phthalates, especially via monitoring the level of activation of their immune state.
Laboratoire GEPV - CNRS, UMR 8198 Université des Sciences et Technologies de Lille1, Villeneuve d'Ascq, France. Electronic address: virginie.cuvillier@univ-lille1.fr.
Virginie
V
Cuvillier-Hot
Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA) - CNRS, UMR 5023 Université Lyon1, Villeurbanne, France.
Karine
K
Salin
IRBI, Institut de Recherche sur la Biologie de l'Insecte, Université François Rabelais, UMR CNRS 7261, Tours, France.
Séverine
S
Devers
Laboratoire GEPV - CNRS, UMR 8198 Université des Sciences et Technologies de Lille1, Villeneuve d'Ascq, France.
Aurélie
A
Tasiemski
Laboratoire GEPV - CNRS, UMR 8198 Université des Sciences et Technologies de Lille1, Villeneuve d'Ascq, France.
Pauline
P
Schaffner
IRBI, Institut de Recherche sur la Biologie de l'Insecte, Université François Rabelais, UMR CNRS 7261, Tours, France.
Raphaël
R
Boulay
Laboratoire GEPV - CNRS, UMR 8198 Université des Sciences et Technologies de Lille1, Villeneuve d'Ascq, France.
Sylvain
S
Billiard
IRBI, Institut de Recherche sur la Biologie de l'Insecte, Université François Rabelais, UMR CNRS 7261, Tours, France.
Alain
A
Lenoir
D000818:Animals; D001000:Ants / Q000187:drug effects* / Q000276:immunology; D004051:Diethylhexyl Phthalate / Q000633:toxicity*; D004785:Environmental Pollutants / Q000633:toxicity*; D005247:Feeding Behavior / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D052287:Oviparity / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects
D004785:Environmental Pollutants; D004051:Diethylhexyl Phthalate
Biomarker; DEHP; Immunity; Oxidative stress; Phthalates