Oil sands process-affected water (OSPW) — a byproduct of the oil sands industry in Northern Alberta, Canada – is currently stored in on-site tailings ponds. The goal of the present study was to investigate the interaction of OSPW with the olfactory system and olfactory-mediated behaviours of fish upon the first encounter with OSPW. The response of rainbow trout (Oncorhynchus mykiss) to different concentrations (0.1, 1, and 10%) of OSPW was studied using a choice maze and electro-olfactography (EOG), respectively. The results of the present study showed that rainbow trout are capable of detecting and avoiding OSPW at a concentration as low as 0.1%. Exposure to 1% OSPW impaired (i.e. reduced sensitivity) the olfactory response of rainbow trout to alarm and food cues within 5 min or less. The results of the present study demonstrated that fish could detect and avoid minute concentrations of OSPW. However, if fish were exposed to OSPW-contaminated water and unable to escape, their olfaction would be impaired.

International audience | Pesticides have long been used as the main solution to limit agricultural pests, but their widespread use resulted in chronic or diffuse environmental pollutions, development of insect resistances, and biodiversity reduction. The effects of low residual doses of these chemical products on organisms that affect both targeted species (crop pests) but also beneficial insects became a major concern, particularly because low doses of pesticides can induce unexpected positive-also called hormetic-effects on insects, leading to surges in pest population growth at greater rate than what would have been observed without pesticide application. The present study aimed to examine the effects of sublethal doses of deltamethrin, one of the most used synthetic pyrethroids, known to present a residual activity and persistence in the environment, on the peripheral olfactory system and sexual behavior of a major pest insect, the cotton leafworm Spodoptera littoralis. We highlighted here a hormetic effect of sublethal dose of deltamethrin on the male responses to sex pheromone, without any modification of their response to host-plant odorants. We also identified several antennal actors potentially involved in this hormetic effect and in the antennal detoxification or antennal stress response of/to deltamethrin exposure

International audience | Insecticides have long been used as the main method in limiting agricultural pests, but their widespread use has resulted in environmental pollution, development of resistances, and biodiversity reduction. The effects of insecticides at low residual doses on both the targeted crop pest species and beneficial insects have become a major concern. In particular, these low doses can induce unexpected positive (hormetic) effects on pest insects, such as surges in population growth exceeding what would have been observed without pesticide application. Methomyl and chlorpyrifos are two insecticides commonly used to control the population levels of the cotton leafworm Spodoptera littoralis, a major pest moth. The aim of the present study was to examine the effects of sublethal doses of these two pesticides, known to present a residual activity and persistence in the environment, on the moth physiology. Using a metabolomic approach, we showed that sublethal doses of methomyl and chlorpyrifos have a systemic effect on the treated insects. We also demonstrated a behavioral disruption of S. littoralis larvae exposed to sublethal doses of methomyl, whereas no effects were observed for the same doses of chlorpyrifos. Interestingly, we highlighted that sublethal doses of both pesticides did not induce a change in acetylcholinesterase activity in head of exposed larvae

L'olfactometrie ou la mesure des odeurs par analyse sensorielle permet de quantifier les odeurs. Les methodes disponibles donnent acces a la mesure de trois grandeurs: la concentration d'odeur, l'intensite de l'odeur et la gene olfactive. Dans les deux premiers cas, la mesure fait appel a un jury d'experts preselectionnes et dans le troisieme cas, la methode fait appel a un jury de population locale. Il est ainsi possible, non seulement de caracteriser les sources d'odeur et de les comparer entre elles, mais aussi de caracteriser l'environnement d'une source d'odeur

The impact of climate change drivers on cultivated plants and pest insects has come into research focus. One of the most significant drivers is atmospheric carbon dioxide, which is converted into primary plant metabolites by photosynthesis. Increased atmospheric CO2 concentrations therefore affect plant chemistry. The chemical composition of non-volatile and volatile organic compounds of plants is used by insects to locate and identify suitable host plants for feeding and reproduction. We investigated whether elevated CO2 concentrations in the atmosphere affect the plant-pest interaction in a fruit crop of high economic importance in Europe. Therefore, potted pear trees were cultivated under specified CO2 conditions in a Free-Air Carbon dioxide Enrichment (FACE) facility at Geisenheim University in Germany for up to 14 weeks, beginning from bud swelling. We compared emitted volatiles from these pear trees cultivated for 7 and 14 weeks under two different CO2 levels (ambient: ca. 400 ppm and elevated: ca. 450 ppm CO2) and their impact on pest insect behavior. In total, we detected and analyzed 76 VOCs from pear trees. While we did not detect an overall change in VOC compositions, the relative release of single compounds changed in response to CO2 increase. Differences in VOC release were inconsistent over time (phenology stages) and between study years, indicating interactions with other climate parameters, such as temperature. Even though insect-plant interaction can rely on specific volatile compounds and specific mixtures of compounds, respectively, the changes of VOC patterns in our field study did not impact the host choice behavior of C. pyri females. In olfactometer trials, 64% and 60% of the females preferred the odor of pear trees cultivated under elevated CO2 for 7 and 14 weeks, respectively, over the odor from pear trees cultivated under ambient CO2. In binary-choice oviposition assays, C. pyri females laid most eggs on pears during April 2020; on average, 51.9 (± 51.3) eggs were laid on pears cultivated under eCO2 and 60.3 (± 48.7) eggs on aCO2.

Insecticides have long been used as the main method in limiting agricultural pests, but their widespread use hasresulted in environmental pollution, development of resistances, and biodiversity reduction. The effects of insecticides at low residual doses on both the targeted crop pest species and beneficial insects have become a major concern. In particular, these low doses can induce unexpected positive (hormetic) effects on pest insects, such as surges in population growth exceeding what would have been observed without pesticide application. Methomyl and chlorpyrifos are two insecticides commonly used to control the population levels of the cotton leafworm Spodoptera littoralis, a major pest moth. The aim of the present study was to examine the effects ofsublethal doses of these two pesticides, known to present a residual activity and persistence in the environment, on the moth physiology. Using a metabolomic approach, we showed that sublethal doses of methomyl and chlorpyrifos have a systemic effect on the treated insects. We also demonstrated a behavioral disruption of S. littoralis larvae exposed to sublethal doses of methomyl, whereas no effects were observed for the same doses of chlorpyrifos. Interestingly, we highlighted that sublethal doses of both pesticides did not induce a change in acetylcholinesterase activity in head of exposed larvae.