An Old World leaf-cutting, fungus-growing ant: A case of convergent evolution.

The African myrmicine ant Crematogaster clariventris is a territorially dominant arboreal species that constructs very hard carton nests. Noting that workers cut off leaves from different plant species while building or repairing their nests, we asked ourselves if there was a correlation. We conducted scanning electron microscopic observations of nest walls that revealed the presence of fungal mycelia. As the presence of filamentous Ascomycota has been shown on arboreal ant nests worldwide, we used a metabarcoding approach and, indeed, noted the presence of Operational Taxonomic Unit (OTU) Cre_006041 of the Capnodiales known to reinforce large nests of an unidentified African Crematogaster. This OTU was also recorded in the workers' bodies. At a very low level, we also noted OTU Cre_320021 of the Chaetothyriales known for their relationships with the African plant-ant species C. margaritae. Therefore, by cutting leaves and growing fungus, C. clariventris illustrates a case of convergent evolution with higher New World leaf-cutting, fungus-growing Attina of the genera Acromyrmex, Amoimyrmex and Atta. However, there are notable differences. Leaf-cutting Attina cultivate Agaricaceae (Basidiomycota) for food, whereas C. clariventris uses Capnodiales to reinforce their nests (i.e., after the mycelium died, the hyphae's cell walls remained sturdy forming a natural composite material), have a distinct geographical origin (i.e., New World vs. Old World) and belong to a distinct ant tribe in the subfamily Myrmicinae (i.e., Attini vs. Crematogastrini). Furthermore, leaf-cutting Attina evolved an efficacious means of cutting leaves by using their mandibles asymmetrically, whereas C. clariventris workers, typically, use their mandibles symmetrically.

Limited impact of several years of pretreated wastewater discharge on fauna and vegetation in a mangrove ecosystem.

It was hypothesized that mangroves, tropical wetlands, could be used for the finishing treatment of domestic wastewaters. Our aim was to determine if a nutrient-stressed mangrove could tolerate long-term discharges of pretreated wastewater (PW). Since 2008, in an in situ experimental system set up in Mayotte Island (Indian Ocean), domestic PW are discharged into two impacted areas (675 m2) dominated by different species of mangrove trees. Anthropogenic inputs during > 4.5 years led to an increase in vegetation growth associated with an increase in leaf pigment content, leaf surface and tree productivity. A marked increase in tree mortality was observed. There was no effect on crabs and meiofauna densities, but significant modifications of community structures. These effects may be directly linked to PW inputs, or indirectly to the modifications of the environment associated with higher tree growth. However, our results indicate that there was no major dysfunction the ecosystem.

[Assisted reproductive technologies for serodiscordant couples: desire for child and pregnancy versus the fact of illness]. / Couples sérodifférents dont l'homme est infecté par le VIH et Assistance médicale à la procréation: le désir d'enfant et la grossesse aux prises avec la réalité de la maladie.

Assisted Reproductive Technologies for serodiscordant couples with HIV-infected male partner has been possible since 2000 in French centres such as the CECOS in Toulouse. From the outset, couples in the program meet psychologists or psychiatrists. In the first instance, the results from 40 psychologist led interviews with serodiscordant couples held at the CECOS in Toulouse, identified several challenging ideas. Couples who plan to have children were in a stable long-term relationship and both were involved in managing the illness. Medically assisted procreation awakens in the women a strong desire for children and enables the couples to make plans for the future. But it also reminds the men of their reliance on medical assistance because of the demands made by the medical program, and in case of failure it can destabilise the couples' way of coping with HIV. Subsequently, interviews with 12 couples during pregnancy revealed the overbearing presence of the illness, despite the imminent birth of the desired child. In their responses, women express their anxiety concerning the risk of contamination, and the defences that the men had built up to cope with HIV appeared destabilised, now that the idea of their death is rekindled.