Senescence of the cellular immune response in Drosophila melanogaster

Immune system effectiveness generally declines as animals age, compromising disease resistance. In Drosophila, expression of a variety of immune-related genes elevates during ageing; however how this is linked to increasing pathogen susceptibility in older flies has remained unclear. We investigated whether changes in the Drosophila cellular immune response might contribute to immunosenescence. Experiments studied fly cohorts of different ages and compared the numbers and activity of the circulating haemocytes involved in pathogen defence. In female wildtype Samarkand and Oregon R flies the haemocyte population fell by 31.8% and 10.2% respectively during the first four weeks of adulthood. Interestingly we detected no such decline in male flies. The impact of ageing on the phagocytic activity of haemocytes was investigated by injecting flies with fluorescently labelled microbes or latex beads and assessing the ability of haemocytes to engulf them. For all immune challenges the proportion of actively phagocytosing haemocytes decreased as flies aged. Whilst 24.3% ± 1.15% of haemocytes in one-week-old flies phagocytosed Escherichia coli bacteria or Beauveria bassiana fungal spores, this decreased to 16.7% ± 0.99% in four-week-old flies. This clear senescence of the Drosophila cellular immune response may underpin increased disease susceptibility in older flies

A Revision of Malagasy Species of Anochetus Mayr and Odontomachus Latreille (Hymenoptera: Formicidae)

Species inventories are essential for documenting global diversity and generating necessary material for taxonomic study and conservation planning. However, for inventories to be immediately relevant, the taxonomic process must reduce the time to describe and identify specimens. To address these concerns for the inventory of arthropods across the Malagasy region, we present here a collaborative approach to taxonomy where collectors, morphologists and DNA barcoders using cytochrome c oxidase 1 (CO1) participate collectively in a team-driven taxonomic process. We evaluate the role of DNA barcoding as a tool to accelerate species identification and description. This revision is primarily based on arthropod surveys throughout the Malagasy region from 1992 to 2006. The revision is based on morphological and CO1 DNA barcode analysis of 500 individuals. In the region, five species of Anochetus (A

Worker thelytoky allows requeening of orphaned colonies but increases susceptibility to reproductive cheating in an ant

The file contains the microsatellite genotypes of the individuals used in the paper by Doums et al. Animal Behaviour (2017). Each line corresponds to an individual with its identity, enclosure number (enclosure 7 is missing), nest number, nest origin (QR = from queenright colony , QL = from queenless colony), its caste (male, foreignmale, diploidmale, worker, gyne, queen), its age (found at the pupal stage, as callow or adult), and its genotypes. For each microsatellite locus, the two alleles are given in two separated column labelled by the locus name and the allele number (a or b). Missing data or the second allele of haploid genotypes is indicated by NA

Dataset for the paper worker thelytoky allows requeening of orphaned colonies but increases susceptibility to reproductive cheating in an ant

The file contains the microsatellite genotypes of the individuals used in the paper by Doums et al. Animal Behaviour (2017). Each line corresponds to an individual with its identity, enclosure number (enclosure 7 is missing), nest number, nest origin (QR = from queenright colony , QL = from queenless colony), its caste (male, foreignmale, diploidmale, worker, gyne, queen), its age (found at the pupal stage, as callow or adult), and its genotypes. For each microsatellite locus, the two alleles are given in two separated column labelled by the locus name and the allele number (a or b). Missing data or the second allele of haploid genotypes is indicated by NA

Facultative use of thelytokous parthenogenesis for queen production in the polyandrous ant Cataglyphis cursor

he evolutionary paradox of sex remains one of the major debates in evolutionary biology. The study of species capable of both sexual and asexual reproduction can elucidate factors important in the evolution of sex. One such species is the ant Cataglyphis cursor, where the queen maximizes the transmission of her genes by producing new queens (gynes) asexually while simultaneously maintaining a genetically diverse workforce via the sexual production of workers. We show that the queen can also produce gynes sexually and may do so to offset the costs of asexual reproduction. We genotyped 235 gynes from 18 colonies and found that half were sexually produced. A few colonies contained both sexually and asexually produced gynes. Although workers in this species can also use thelytoky, we found no evidence of worker production of gynes based on genotypes of 471 workers from the six colonies producing sexual gynes. Gynes are thus mainly, and potentially exclusively, produced by the queen. Simulations of gynes inbreeding level following one to ten generations of automictic thelytoky suggest that the queen switches between or combines thelytoky and sex, which may reduce the costs of inbreeding. This is supported by the relatively small size of inbred gynes in one colony, although we found no relationship between the level of inbreeding and immune parameters. Such facultative use of sex and thelytoky by individual queens contrasts with other known forms of parthenogenesis in ants, which are typically characterized by distinct lineages specializing in one strategy or the other.Peer reviewe

Dataset for the paper worker thelytoky allows requeening of orphaned colonies but increases susceptibility to reproductive cheating in an ant

The file contains the microsatellite genotypes of the individuals used in the paper by Doums et al. Animal Behaviour (2017). Each line corresponds to an individual with its identity, enclosure number (enclosure 7 is missing), nest number, nest origin (QR = from queenright colony , QL = from queenless colony), its caste (male, foreignmale, diploidmale, worker, gyne, queen), its age (found at the pupal stage, as callow or adult), and its genotypes. For each microsatellite locus, the two alleles are given in two separated column labelled by the locus name and the allele number (a or b). Missing data or the second allele of haploid genotypes is indicated by NA.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Worker thelytoky allows requeening of orphaned colonies but increases susceptibility to reproductive cheating in an ant

The file contains the microsatellite genotypes of the individuals used in the paper by Doums et al. Animal Behaviour (2017). Each line corresponds to an individual with its identity, enclosure number (enclosure 7 is missing), nest number, nest origin (QR = from queenright colony , QL = from queenless colony), its caste (male, foreignmale, diploidmale, worker, gyne, queen), its age (found at the pupal stage, as callow or adult), and its genotypes. For each microsatellite locus, the two alleles are given in two separated column labelled by the locus name and the allele number (a or b). Missing data or the second allele of haploid genotypes is indicated by NA.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Spring colonies of the ant Temnothorax nylanderi tolerate cadmium better than winter colonies, in both a city and a forest habitat

International audienceA recent study showed that, in the ant Temnothorax nylanderi, city colonies are more tolerant to cadmium than forest colonies. However, because of annual variation in biological factors (e.g. body size, anti-stress protein production or trace metal accumulation rate), trace metal tolerance may vary over the year. We aimed at testing whether tolerance to cadmium of colonies of T. nylanderi differs between two different seasons within the same year (winter and spring). We also assessed whether the better cadmium tolerance of city colonies was constant over these two different time points. We collected colonies at the end of their hibernation period (winter colonies) and several weeks after (spring colonies) from two different habitats (forest and city) to assess whether response to cadmium was consistent regardless of the environment. We exposed colonies to a cadmium or a control treatment for 61 days. We compared tolerance to cadmium between spring/winter and city/forest colonies by measuring several life history traits. We found that spring colonies tolerates cadmium better than winter colonies, and that city colonies have a higher tolerance to cadmium but only in spring. Although further studies with replicated pairs of city/forest habitats and different years will be necessary to confirm those results, our study suggests that tolerance to trace metals can fluctuate along the yearly cycle

No evidence of pre-copulatory mate choice by gynes in the facultatively parthenogenetic ant Cataglyphis cursor

International audienceVirgin queens (gynes) of the ant Cataglyphis cursor mate on the ground at the nest entrance, where they benefit from the protection of nestmate workers. By carrying out mating tests in the laboratory, we show that gynes mate with the first males they encounter, suggesting the absence of pre-copulatory mate choice by gynes. This is in agreement with the recent finding that workers behave aggressively towards foreign males and could thereby exercise a form of inclusive mate choice, which could replace pre-copulatory mate choice by gynes

Spring colonies of the ant Temnothorax nylanderi tolerate cadmium better than winter colonies, in both a city and a forest habitat

International audienceA recent study showed that, in the ant Temnothorax nylanderi, city colonies are more tolerant to cadmium than forest colonies. However, because of annual variation in biological factors (e.g. body size, anti-stress protein production or trace metal accumulation rate), trace metal tolerance may vary over the year. We aimed at testing whether tolerance to cadmium of colonies of T. nylanderi differs between two different seasons within the same year (winter and spring). We also assessed whether the better cadmium tolerance of city colonies was constant over these two different time points. We collected colonies at the end of their hibernation period (winter colonies) and several weeks after (spring colonies) from two different habitats (forest and city) to assess whether response to cadmium was consistent regardless of the environment. We exposed colonies to a cadmium or a control treatment for 61 days. We compared tolerance to cadmium between spring/winter and city/forest colonies by measuring several life history traits. We found that spring colonies tolerates cadmium better than winter colonies, and that city colonies have a higher tolerance to cadmium but only in spring. Although further studies with replicated pairs of city/forest habitats and different years will be necessary to confirm those results, our study suggests that tolerance to trace metals can fluctuate along the yearly cycle