Farm ponds make a contribution to the biodiversity of aquatic insects in a French agricultural landscape

Manmade ecosystems provide a variety of resources that have strong economic values. We assessed the importance of 37 farm ponds for the biodiversity of Odonata in an agricultural landscape lacking natural wetlands in southwestern France. Farm ponds captured 40% of the regional species pool, including both common and rare species. The species assemblages were not correlated with pond use (e.g., cattle watering, duck farming, etc.) or to landscape variable. Species richness was correlated with pond area, suggesting that community diversity was primarily driven by autoecological processes. Farm ponds thus made a positive contribution to the maintenance of aquatic biodiversity. This added value for biodiversity should be considered when calculating the costs and benefits of constructing water bodies for human activities.     

In vitro inhibitory effect of cranberry (Vaccinium macrocarpom Ait.) juice on pathogenic microorganisms

The purpose of this study was to determine the inhibitory effects of cranberry juice on pathogenic microorganisms. The microorganisms analyzed were Escherichia coli from patients with urinary infections, Salmonella spp., Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus. The disc method was used to determine the sensitivity of bacteria to cranberry juice (CJ, both concentrated and diluted). A lawn of 10(6) cfu/ml was grown on agar surfaces in Petri dishes and on Whatman discs that had been previously saturated with CJ and CJ : water 1 : 1 to 1 : 50 juice solutions had been placed on the discs, which were cultured and incubated. The results indicated that S. aureus was more susceptible to cranberry juice inhibition than the other microorganisms. L. monocytogenes was the most resistant to the inhibitory action of cranberry juice, showing a significant difference from the inhibition of P. aeruginosa, uropathogenic E. coli, Salmonella spp., and S. aureus. This study also demonstrated that the inhibitory activity of cranberry juice for E. coli took place up to a dilution of 1 : 20.     

Ecological, morphological and phylogenetic correlates of interspecific variation in plasma carotenoid concentration in birds

Carotenoids are important as pigments for bright coloration of animals, and as physiologically active compounds with a wide array of health-related benefits. However, the causes of variation in carotenoid acquisition and physiology among species are poorly known. We measured the concentration of carotenoids in the blood of 80 wild bird species differing in diet, body size and the extent of carotenoid-based traits. Preliminary analyses showed that diet significantly explains interspecific variability in plasma carotenoids. However, dietary influences were apparently overridden by phylogenetic relationships among species, which explained most (65%) of this variability. This phylogenetic effect could be due partly to its covariation with diet, but may also be caused by interspecific differences in carotenoid absorption from food to the blood stream, mediated, for example by endothelial carriers or gut parasites. Carotenoid concentrations also decreased with body size (which may be explained by the allometric relationship between ingestion rate and body mass), and correlated positively with the extent of carotenoid-dependent coloration of plumage and bare parts. Therefore, the acquisition of carotenoids from the diet and their use for both health and display functions seem to be constrained by ecological and physiological aspects linked to the phylogeny and size of the species.     

γδ T lymphocytes from cystic fibrosis patients and healthy donors are high TNF-α and IFN-γ-producers in response to Pseudomonas aeruginosa

Background

γδ T cells have an important immunoregulatory and effector function through cytokine release. They are involved in the responses to Gram-negative bacterium and in protection of lung epithelium integrity. On the other hand, they have been implicated in airway inflammation.

Methods

The aim of the present work was to study intracytoplasmic IL-2, IL-4, IFN-γ and TNF-α production by γδ and αβ T lymphocytes from cystic fibrosis patients and healthy donors in response to Pseudomonas aeruginosa (PA). Flow cytometric detection was performed after peripheral blood mononuclear cells (PBMC) culture with a cytosolic extract from PA and restimulation with phorbol ester plus ionomycine. Proliferative responses, activation markers and receptor usage of γδ T cells were also evaluated.

Results

The highest production of cytokine was of TNF-α and IFN-γ, γδ being better producers than αβ. No differences were found between patients and controls. The Vγ9δ2 subset of γδ T cells was preferentially expanded. CD25 and CD45RO expression by the αβ T subset and PBMC proliferative response to PA were defective in cystic fibrosis lymphocytes.

Conclusion

Our results support the hypothesis that γδ T lymphocytes play an important role in the immune response to PA and in the chronic inflammatory lung reaction in cystic fibrosis patients. They do not confirm the involvement of a supressed Th1 cytokine response in the pathogenesis of this disease.     

Sexual size dimorphism in shorebirds, gulls, and alcids: the influence of sexual and natural selection

Abstract. Charadrii (shorebirds, gulls, and alcids) have an unusual diversity in their sexual size dimorphism, ranging from monomorphism to either male-biased or female-biased dimorphism. We use comparative analyses to investigate whether this variation relates to sexual selection through competition for mates or natural selection through different use of resources by males and females. As predicted by sexual selection theory, we found that in taxa with socially polygynous mating systems, males were relatively larger than females compared with less polygynous species. Furthermore, evolution toward socially polyandrous mating systems was correlated with decreases in relative male size. These patterns depend on the kinds of courtship displays performed by males. In taxa with acrobatic flight displays, males are relatively smaller than in taxa in which courtship involves simple flights or displays from the ground. This result remains significant when the relationship with mating system is controlled statistically, thereby explaining the enigma of why males are often smaller than females in socially monogamous species. We did not find evidence that evolutionary changes in sexual dimorphism relate to niche division on the breeding grounds. In particular, biparental species did not have greater dimorphism in bill lengths than uniparental species, contrary to the hypothesis that selection for ecological divergence on the breeding grounds has been important as a general explanation for patterns of bill dimorphism. Taken together, these results strongly suggest that sexual selection has had a major influence on sexual size dimorphism in Charadrii, whereas divergence in the use of feeding resources while breeding was not supported by our analyses.     

Time of day, age and feeding habits influence coccidian oocyst shedding in wild passerines

Protozoan coccidia are one of the most common intestinal parasites in birds. Ordinary coccidian detection and quantification techniques have proved to be inaccurate for wild passerines due to the existence of marked oocyst shedding rhythms throughout the day. Previous studies have suggested that these rhythms should be taken into account when analysing coccidian load and prevalence data, but their pattern and magnitude still remain poorly known. In this study we characterised shedding rhythms in the field by means of 406 samples of faeces taken from two species of passerines with different diets: the European Serin (a granivorous species), and the Garden Warbler (an insectivorous species). Both coccidian prevalence and load were two-phased, with maximums occurring in the afternoon. Oocyst elimination remained consistently high during the second half of the day, whereas prevalence peaked during the afternoon, lowering throughout the evening. This pattern was found in both species. We found a high repeatability of prevalence and intensity when differences between the morning and afternoon were statistically controlled. As a result, we suggest that sampling periods used in the analysis of coccidian prevalence and/or load studies should take into account these differences in times of shedding and be limited to the afternoon, otherwise a statistical control of this factor will be required.     

Louse flies of Eleonora’s falcons that also feed on their prey are evolutionary dead‐end hosts for blood parasites

Host shifts are widespread among avian haemosporidians, although the success of transmission depends upon parasite‐host and parasite‐vector compatibility. Insular avifaunas are typically characterized by a low prevalence and diversity of haemosporidians, although the underlying ecological and evolutionary processes remain unclear. We investigated the parasite transmission network in an insular system formed by Eleonora's falcons (the avian host), louse flies that parasitize the falcons (the potential vector), and haemosporidians (the parasites). We found a great diversity of parasites in louse flies (16 Haemoproteus and 6 Plasmodium lineages) that did not match with lineages previously found infecting adult falcons (only one shared lineage). Because Eleonora's falcon feeds on migratory passerines hunted over the ocean, we sampled falcon kills in search of the origin of parasites found in louse flies. Surprisingly, louse flies shared 10 of the 18 different parasite lineages infecting falcon kills. Phylogenetic analyses revealed that all lineages found in louse flies (including five new lineages) corresponded to Haemoproteus and Plasmodium parasites infecting Passeriformes. We found molecular evidence of louse flies feeding on passerines hunted by falcons. The lack of infection in nestlings and the mismatch between the lineages isolated in adult falcons and louse flies suggest that despite louse flies’ contact with a diverse array of parasites, no successful transmission to Eleonora's falcon occurs. This could be due to the falcons’ resistance to infection, the inability of parasites to develop in these phylogenetically distant species, or the inability of haemosporidian lineages to complete their development in louse flies.     

Blood parasites, leucocytes and plumage brightness in the Cirl Bunting, Emberiza cirlus

1. Although a female preference for pairing with brightly plumaged males has been reported in many species, the reasons for this choice are not fully understood.
2. Parasites have been proposed as playing an important role in shaping these preferences because, by pairing with brightly coloured individuals, females can obtain parasite-free and/or more healthy mates.
3. In this paper one of the predictions of this hypothesis is tested, namely a higher health level in brightly coloured individuals, by analysing the relationships among blood parasites, leucocyte levels and plumage brightness in the Cirl Bunting, Emberiza cirlus .
4. Two species of blood parasites were detected. Whereas a lower body condition was detected in individuals infected by Leucocytozoon cambournaci, no such differences were associated with Plasmodium relictum infections. Infected individuals showed higher total leucocyte counts than non-infected individuals.
5. Colour intensity of carotenoid derived colorations was negatively correlated to the relative proportion of lymphocytes and positively correlated to the relative presence of heterophils. Furthermore, the size of yellow feathered areas was positively correlated with the absolute number of leucocytes and the relative presence of heterophils. Only some of these relationships were found for non-carotenoid derived traits.
6. These results suggest that male plumage yellow coloration in the Cirl Bunting is a reliable indicator of health status and supports the hypothesis that females obtain more parasite-free mates if they pair with brightly coloured individuals.     

Colonization and dispersal patterns of the invasive American brine shrimp Artemia franciscana (Branchiopoda: Anostraca) in the Mediterranean region

Cysts of the brine shrimp Artemia franciscana are harvested from the Great Salt Lake (GSL) and San Francisco Bay (SFB) saltworks in the USA, and marketed worldwide to provide live food for aquaculture. This species has become invasive across several countries. We investigated (1) if the introduced populations in the Mediterranean region could have originated from these USA populations, (2) how the genetic diversity of Mediterranean compares to that at GSL and SFB, and (3) if genetic patterns in the Mediterranean can shed light on colonization routes. We sequenced a fragment of the cytochrome c oxidase subunit I and screened microsatellites loci from Mediterranean populations and the two putative USA sources. Haplotypes from Mediterranean populations were identical or closely related to those from SFB and GSL, and not related to other available American populations. Microsatellite analyses showed a reduced population diversity for most Mediterranean populations suggesting bottleneck effects, but few populations were showing similar or higher genetic diversity than native ones, which are likely to be admixed from both GSL and SFB because of multiple introductions. Results suggest natural dispersal, potentially via flamingos, between two Spanish populations. Our analyses show that all invaded populations could have originated from those commercialized USA populations.     

Facultative and non‐facultative sex ratio adjustments in a dimorphic bird species

If parental allocation to each offspring sex has the same cost/benefit ratio, Fisher's hypothesis predicts a sex ratio biased towards the cheaper sex. However, in dimorphic birds there is little evidence for this, especially at hatching. We investigated the pre‐fledgling 1) sex ratio, 2) body condition and 3) sex‐differential mortality in a population of the glossy ibis Plegadis falcinellus, in southern Spain between 2001 and 2011. We defined two age groups for the period between hatching and fledging. We also compared pre‐fledgling with the autumn sex ratio. Metabolic rates were estimated by the doubly labeled water (DLW) technique to establish that sons (the bigger sex) were 18% more energy demanding than daughters, and to compute the predicted Fisher's sex ratio (0.465). As population size increased between years, body condition decreased in both sexes, and mortality increased more for daughters than sons prior to fledging. At the same time, the proportion of males among chicks close to fledging increased (average sex ratio: 0.606) while the proportion close to hatching decreased (average sex ratio: 0.434, in line with Fisher's prediction). Furthermore, the proportions of males at fledging and the following autumn were negatively correlated across years. We suggest that, as population density increased and conditions worsened the larger sex had relatively higher survival. These differences in survival produce a shift from a facultative female‐biased sex ratio at hatching into a non‐facultative male‐biased sex ratio of fledglings. Additionally, the excess of males at fledging was counterbalanced by sex‐related dispersal during the autumn. Overall, glossy ibis sex ratio is a product of a combination of facultative and non‐facultative adjustments triggered by environmental conditions, driven by rapid population growth, and mediated by highly interrelated life‐history traits such as body condition, mortality, and dispersal.