Analytical development for the assessment of pesticide contaminations in blood and plasma of wild birds: The case of grey partridges (Perdix perdix).

In this study, blood and plasma of grey partridges (Perdix perdix) were analyzed to assess their potential contamination by plant protection products (PPP) and especially pesticide compounds. The group of pesticides selected is composed of a huge variety of compounds. Therefore, in this study, two methods were optimized and validated to analyze 104 compounds including herbicides, insecticides, fungicides and photoprotectors or synergists. Various extraction methods found in the literature were compared and adapted for the extraction of pesticides from blood and plasma. After extraction, samples were concentrated then injected for quantification simultaneously in LC-MS/MS and ATD-GC-MS/MS with an automatic thermal desorption step (ATD). Both LC-MS/MS and ATD-GC-MS/MS analyses were performed using the MRM mode with 2 mass transitions for each compound.The two analytical methods achieved a good linearity for the calibration responses in plasma and blood. Methods allowed sensitive detection and quantification in complex biological matrices such as plasma and blood in both LC and GC. For plasma samples and considering all 104 compounds of the study, the average LOD was 0.005 ng mg-1 in LC-MS/MS and 0.035 ng mg-1 in ATD-GC-MS/MS and the average LOQ was 0.017 ng mg-1 and 0.116 ng mg-1 in LC-MS/MS and ATD-GC-MS/MS respectively. Accordingly, the average LOD for blood samples was 0.011 ng mg-1 in LC and 0.028 ng mg-1 in GC whereas the average LOQ was 0.038 ng mg-1 and 0.094 ng mg-1 in LC-MS/MS and ATD-GC-MS/MS respectively. Those analytical methods were then successfully applied to 70 blood samples and 35 plasma samples.

Fine-scale genetic structure in a high dispersal capacity raptor, the Montagu's harrier (Circus pygargus), revealed by a set of novel microsatellite loci.

The Montagu's harrier (Circus pygargus) is a semi-colonial raptor species widely but patchily distributed across the Palearctic region with recorded cases of philopatry and presence of extra-pair copulation. In order to assess Montagu's harrier spatial genetic structure and contemporary gene flow, we developed 16 new microsatellite markers using 454 pyrosequencing. Genotypes of 117 chicks sampled in a 200 × 300 km farmland area in Central Western France were analyzed to characterize genetic polymorphism at each locus and regional and fine-scale genetic structure. Fourteen markers were found polymorphic, with a number of alleles ranging from 3 to 11. The expected and observed heterozygosities ranged from 0.36 to 0.856 and from 0.35 to 0.868, respectively. A single genetic unit was found at the regional scale with higher genetic similarity observed at a small spatial scale (up to 10 km). Our results are consistent with overall large-scale juvenile and adult dispersal together with small-scale male philopatry. Cross-species amplification of this set of microsatellites makers has been successful in two closely related harrier species: the marsh harrier (Circus aeruginosus) and the Hen harrier (Circus cyaneus) for which 14 and 12 markers were polymorphic, respectively. These new microsatellite markers could be used to study the population genetic structure, contemporary gene flow and parentage analyses in these three species and to conduct microsatellite-based demographic inferences on the Montagu's harrier.

Evaluation of competition between a native and an invasive hornet species: do seasonal phenologies overlap?

One common dogma in ecology is based on the competitive exclusion principle. Hence, competition is often considered to be one of the primary determinants of the structure and functioning of ecosystems. In this paper, we investigate how the native Vespa crabro and the recently introduced Vespa velutina show some degree of niche differentiation that potentially minimizes their interspecific competition, the two dimensions investigated here being seasonal activity patterns and preferences for food. These two species share common characteristics: they are closely related, live in the same areas, belong to the same guild (predators), exploit the same kind of food sources, and exhibit a similar annual life cycle. Considering all these similarities, interspecific competition may occur if the two species exhibit identical seasonal phenologies. Our data show that their seasonal phenologies overlap to some extent probably due to biological constraints common to Vespinae. The shifts in time observed here allow the hornet species to not directly compete for food sources at the same time. It does not however exclude indirect competition, especially in a 'first-come, first-served' fashion.

Larval intraspecific competition for food in the European grapevine moth Lobesia botrana.

Effective pest management with lower amounts of pesticides relies on accurate prediction of insect pest growth rates. Knowledge of the factors governing this trait and the resulting fitness of individuals is thus necessary to refine predictions and make suitable decisions in crop protection. The European grapevine moth, Lobesia botrana, the major pest of grapes in Europe, is responsible for huge economic losses. Larvae very rarely leave the grape bunch on which they were oviposited and thus cannot avoid intraspecific competition. In this study, we determined the impact of intraspecific competition during the larval stage on development and adult fitness in this species. This was tested by rearing different numbers of larvae on an artificial diet and measuring developmental and reproductive life history traits. We found that intraspecific competition during larval development has a slight impact on the fitness of L. botrana. The principal finding of this work is that larval density has little effect on the life history traits of survivors. Thus, the timing of eclosion, duration of subsequent oviposition, fecundity appears to be more uniform in L. botrana than in other species. The main effect of larval crowding was a strong increase of larval mortality at high densities whereas the probability of emergence, sex ratio, pupal mass, fecundity and longevity of mated females were not affected by larval crowding. Owing to increased larval mortality at high larval densities, we hypothesized that mortality of larvae at high densities provided better access to food for the survivors with the result that more food was available per capita and there were no effect on fitness of survivors. From our results, larval crowding alters the reproductive capacity of this pest less than expected but this single factor should now be tested in interaction with limited resources in the wild.

Different emergence phenology of European grapevine moth (Lobesia botrana, Lepidoptera: Tortricidae) on six varieties of grapes.

The phenology of insect emergence affects reproductive success and is especially critical in short-lived species. An increasing number of studies have documented the effects of thermal and other climatic variations and of unpredictable habitats on the timing of adult insect emergence within and between populations and years. Numerous interacting factors may affect the phenology of adult emergence. Host-plant quality and availability is a key factor that has been largely neglected in studies of the phenology of phytophagous insects. The purpose of this study was to determine the effect of host plant characteristics on the rate of larval growth and the pattern of emergence in a wild population of Lobesia botrana (European grapevine moth), a significant pest in European vineyards. The phenology of emergence differed significantly among the six tested varieties of grapes. The percentage of bunches harboring pupae was similar among the different grape varieties, and the total number of pupae collected was similar to the number of emerging adults per bunch. Among the six varieties of grapes, 0-25 pupae were produced on each bunch. Each of the grape varieties had a single wave of emergence, in which males emerged before females, but their emergence phenology differed significantly in Chardonnay, Chasselas, and Pinot grapes. Both genders had extended durations of emergence in Merlot grapes. Together, the present results show that the characteristics of the grape host plant affect the emergence phenology of L. botrana.