Roe deer exposure to trace metals and pesticides in forests and agricultural plains of North-eastern France.

Human activities related to agriculture and industrial development result in the emission of different types of pollutants in the environment. The phytosanitary pressure depends on the time of the year, the type of habitat, and the used treatments. Wildlife, particularly ungulates, can be exposed to pesticides and trace metals through their herbivorous diet directly impregnated by the environmental contamination. Wild game thus plays a sentinel role but can also represent a risk for human health by exposing venison consumers to these contaminants. The present study explored this dual problem in two types of habitat: forests and agricultural plains located in North-eastern France. Samples of liver and muscle were taken from ten roe deer, five caught on the forests and five others in the plains, to determine contaminant levels. There was no significant difference in contamination of roe deer livers according to the habitat for three trace metals (chromium, nickel, and copper), while lead concentrations were higher in samples from the plain (0.85 vs. 0.74 mg·kg-1 dry matter DM; P < 0.01). Conversely, zinc concentrations were higher in forest roe deer (110 vs. 95 mg·kg-1 DM; P < 0.05). Cadmium concentrations did not differ significantly between the two habitats, but forest samples showed strong inter-individual variability, with some values close to those observed on the plains and others higher (1.8 vs. 0.3 mg·kg-1 DM for forest and plain, respectively; P = 0.11). Mercury was not detected in any sample. The majority of pesticides investigated were not detected. Only a few pesticides were in trace amount (from 1 to 8 µg·kg-1 fresh matter), either in the liver (e.g., heptachlor and oxychlordane) or in both tissues, liver and muscle (e.g., pyridalyl). Some compounds were only detected in plain (e.g., cypermethrin and fenpropidin) and others in forest (piperonyl butoxide and pyridalyl) samples. Analyses mainly detected insecticides in samples taken from forests and agricultural plains. Fungicides and a few herbicides were mainly detected in plain sampled animals. Pesticides and copper concentrations in roe deer tissues were lower than maximum residue levels established for farm (copper) or wild terrestrial (pesticides) animals. Cadmium concentrations were also lower than the maximum level for most samples, except for some forest roe deer. However, both forest and plain roe deer exceeded the maximum level for lead in liver. Human exposure was simulated according to different amounts of meat consumed and compared with toxicological reference values. This study highlighted an overall low risk to human health for both pesticides, copper and lead, with more reservations about cadmium for some roe deer shot in forest. The differences in roe deer contamination between forests and agricultural plains for some trace elements and organic pollutants confirmed the sentinel role of this species.

Sexual segregation in fallow deer: are mixed-sex groups especially unstable because of asynchrony between the sexes?

In gregarious ruminants, females and males tend to live in separate groups outside the rutting season. According to the 'activity budget' hypothesis, this is due to an activity asynchrony between the two sexes reducing the lifetime of mixed-sex groups. We tested this hypothesis in a fallow deer population. Activity asynchrony was more frequent in mixed-sex than in single-sex groups. In addition, mixed-sex groups had a higher probability of splitting-up than all-female groups, and they mainly split up into single-sex groups. However, activity asynchrony did not appear as a major cause of splitting-up.

Comparison of Vertebrate Cytochrome b and Prepronociceptin for Blood Meal Analyses in Culicoides.

To date, studies on host preferences and blood meal identification have been conducted for Culicoides species using molecular-based methods such as PCR techniques to amplify only a fragment from universal vertebrate mitochondrial genes such as cytochrome c oxidase subunit I or cytochrome b (Cyt b). The vertebrate prepronociceptin gene (PNOC) was also tested in this field. However, the choice of molecular marker to identify blood meal is critical. The objective of our study is to compare the ability of Cyt b and PNOC as molecular markers for blood meal identification depending on the stage of blood meal digestion. In order to determine whether these Cyt b and PNOC could provide a positive result, 565 blood-fed females of Culicoides spp were collected and morphologically identified. The samples were collected between 2012 and 2014, in two localities in France. The collection localities were near either livestock or a forest. To catch the specimens, we used UV CDC miniature light traps. PNOC sequence of donkeys (Equus asinus) was sequenced and submitted because it was missing in GenBank. Our findings emphasize that the PNOC marker is not suitable to separate closely related Equid species such as horses and donkeys. The Cyt b marker was able to identify 204 more samples when compared to PNOC (99.55% of specimens). Cyt b appears to be better able to detect the origin of blood meals from females with digested blood in their abdomens. We conclude that Cyt b is a good marker as it increases the accuracy of blood meal identification of engorged females containing digested blood in their abdomens. The host opportunist behavior of Culicoides, especially that of C. obsoletus and C. scoticus, the main vectors of BTV in Europe was also highlighted.