Intraseasonal variation in immune defence, body mass and hematocrit in adult house martins Delichon urbica

The intensity of parasite infections often increases during the reproductive season of the host as a result of parasite reproduction, increased parasite transmission and increased host susceptibility. We report within-individual variation in immune parameters, hematocrit and body mass in adult house martins Delichon urbica rearing nestlings in nests experimentally infested with house martin bugs Oeciacus hirundinis and birds rearing nestlings in initially parasite-free nests. From first to second broods body mass and hematocrit of breeding adult house martins decreased. In contrast leucocytes and immunoglobulins became more abundant. When their nests were infested with ectoparasites adults lost more weight compared with birds raising nestlings in nests treated with pyrethrin, whereas the decrease in hematocrit was more pronounced during infection with blood parasites. Neither experimental infestation with house martin bugs nor blood parasites had a significant effect on the amount of immune defences.

North-African house martins endure greater haemosporidian infection than their European counterparts

Afro-Palearctic migrant species are exposed to parasites at both breeding and over-wintering grounds. The house martin Delichon urbicum is one such migratory species facing high instances of blood parasite infection. In an attempt to determine whether breeding European house martins harbour similar blood parasite communities to populations breeding in North Africa, birds were sampled at their breeding grounds in Switzerland and Algeria. Moreover, haemosporidian prevalence and parasite communities were compared to published data sets on Spanish and Dutch breeding populations. This study furthermore wanted to establish whether co-infection with multiple genera or lineages of parasites had negative effects on host body condition. Breeding house martins caught in Algeria showed a higher prevalence of avian haemosporidian parasites than did European populations. Swiss house martins showed a prevalence comparable to that of Spanish and Dutch populations. There were slight differences in the haemosporidian community between European and North-African populations in terms of composition and abundance of each lineage. Similar to the Dutch house martins, but in contrast to the Spanish population, infection status and number of genera of parasites infecting single hosts did not inFLuence Swiss house martin body condition.

The influence of environmental conditions on immune responses, morphology and recapture probability of nestling house martins (Delichon urbica)

Nestling birds produced later in the season are hypothesized to be of poor quality with a low probability of survival and recruitment. In a Spanish population of house martins (Delichon urbica), we first compared reproductive success, immune responses and morphological traits between the first and the second broods. Second, we investigated the effects of an ectoparasite treatment and breeding date on the recapture rate the following year. Due probably to a reverse situation in weather conditions during the experiment, with more rain during rearing of the first brood, nestlings reared during the second brood were in better condition and had stronger immune responses compared with nestlings from the first brood. Contrary to other findings on house martins, we found a similar recapture rate for chicks reared during the first and the second brood. Furthermore, ectoparasitic house martin bugs had no significant effect on the recapture rate. Recaptured birds had similar morphology but higher immunoglobulin levels when nestlings compared with non-recaptured birds. This result implies that a measure of immune function is a better predictor of survival than body condition per se.

"Indemniser les planteurs pour abolir l'esclavage ? Entre économie, éthique et politique : une étude des débats parlementaires britanniques et français (1788-1848) dans une perspective comparée".

RESUME DE THESEUne majorité d'abolitions dans le Nouveau Monde (1777-1888) donne lieu à l'octroi d'indemnités aux propriétaires d'esclaves. Si cet aspect des émancipations n'a pas retenu l'attention des spécialistes jusqu'à présent, il s'agit d'un phénomène récurrent dans les Amériques. L'étude globale de la question de l'indemnité par l'examen des objectifs d'une telle mesure, de ses enjeux, ainsi que de son coût pour les Etats concernés, constitue ainsi l'ambition de cette recherche.L'originalité de la démarche adoptée réside dans le choix de la comparaison comme mode d'investigation et dans la sélection des débats parlementaires comme sources de travail. Une scène d'investigation sur deux niveaux a été construite. Les processus d'indemnisation britannique et français - jugés les plus représentatifs - ont été traités par le biais de sources, les autres cas par la littérature secondaire. Les discussions tenues de 1788 à 1848 aux Chambres des Communes et des députés ont été isolées comme bases d'investigation.Cette recherche démontre que la question de l'indemnité - bien que délaissée par les historiens qui ne l'ont pas perçue comme telle - constitue une cheville ouvrière d'une émancipation. Bien plus, l'étude du thème de l'indemnité - mesure s'inscrivant dans le concept d'économie morale - élargit l'angle de vue au-delà des seuls enjeux d'une abolition jusqu'à présent privilégiés. Outre des facteurs juridiques et économiques, des éléments sociaux et politiques doivent en effet être considérés, qui permettent de mieux cerner - par le biais de l'indemnité - la problématique complexe d'une abolition.