A multilocus phylogeny of the world Sycoecinae fig wasps (Chalcidoidea: Pteromalidae)

The Sycoecinae is one of five chalcid subfamilies of fig wasps that are mostly dependent on Ficus inflorescences for reproduction. Here, we analysed two mitochondrial ( COI , Cyt b ) and four nuclear genes (ITS2, EF-1α, RpL27a, mago nashi ) from a worldwide sample of 56 sycoecine species. Various alignment and partitioning strategies were used to test the stability of major clades. All topologies estimated using maximum likelihood and Bayesian methods were similar and well resolved but did not support the existing classification. A high degree of morphological convergence was highlighted and several species appeared best described as species complexes. We therefore proposed a new classification for the subfamily. Our analyses revealed several cases of probable speciation on the same host trees (up to 8 closely related species on one single tree of F. sumatrana ), which raises the question of how resource partitioning occurs to avoid competitive exclusion. Comparisons of our results with fig phylogenies showed that, despite sycoecines being internally ovipositing wasps host-switches are common incidents in their evolutionary history. Finally, by studying the evolutionary properties of the markers we used and profiling their phylogenetic informativeness, we predicted their utility for resolving phylogenetic relationships of Chalcidoidea at various taxonomic levels

Palmier, efficacité préventive d'une glu

Un des moyens de protéger les palmiers du papillon palmivore est d’opposer une barrière physique à l’infestation de ces végétaux (effet préventif) et à leur ré-infestation (effet préventif au sens strict(1) mais curatif sur le végétal). Quelle barrière ? Une glu tout simplement, plus facile à utiliser qu’à mettre au point…Un des moyens de protéger les palmiers du papillon palmivore est d’opposer une barrière physique à l’infestation de ces végétaux (effet préventif) et à leur ré-infestation (effet préventif au sens strict(1) mais curatif sur le végétal). Quelle barrière ? Une glu tout simplement, plus facile à utiliser qu’à mettre au point ..

Pitcher Plants Shape Up

International audienc

Evaluation of short mitochondrial metabarcodes for the identification of Amazonian mammals

International audience1. DNA barcoding and metabarcoding are increasingly used as alternatives to traditional morphological identifications. For animals, the standard barcode is a c. 658-bp portion of the COI gene, for which reference libraries now cover a large proportion of described mammal species. Unfortunately, because its sequence is too long and does not contain highly conserved primer binding sites, this marker is not adapted for metabarcoding. Although alternative metabarcodes have been developed, their performances are generally seldom assessed. 2. We evaluate the reliability of a short metabarcode located in the mitochondrial 12S ribosomal RNA for the identifications of Amazonian mammals. We (i) constitute a nearly exhaustive reference library for species found in French Guiana, (ii) assess the taxonomic resolution of the marker and validate its use with dipteran blood meal analyses, (iii) assess the conservation of the primer binding sites, and (iv) compare its theoretical performances with that of a newly designed metabarcode located within the standard COI barcode. 3. About 576 specimens representing 164 species were gathered and sequenced. We show that the 12S marker allows remarkably accurate taxonomic assignations despite its very short size, and that primer binding sites are highly conserved, which is important to avoid PCR amplification bias potentially leading to detection failure. Additionally, our results stress that the identifications should only be considered at the generic level when they are based on incomplete reference libraries, even when a stringent similarity cutoff is used. A new short COI metabarcode was designed based on 569 reference sequences of mammals retrieved on BOLD. Our results clearly show that, while both markers provide similar taxonomic resolution, much higher rates of primer mismatches are found with COI. 4. Besides demonstrating the accuracy of the short 12S marker for the identification of Amazonian mammals and providing a reliable molecular reference database, this study emphasizes that the accuracy of taxonomic assignations highly depends on the comprehensiveness of the reference library and that great caution should be taken for interpreting metabarcoding results based on scarce reference libraries. The comparison with a short COI metabarcode also provides novel evidence in support for the use of ribosomal markers in metabarcoding studies

How Social Structure Drives the Population Dynamics of the Common Vampire Bat (Desmodus rotundus, Phyllostomidae)

International audienceSocial systems are major drivers of population structure and gene flow, with important effects on dynamics and dispersal of associated populations of parasites. Among bats, the common vampire bat (Desmodus rotundus) has likely one of the most complex social structures. Using autosomal and mitochondrial markers on vampires from Mexico, French Guiana, and North Brazil, from both roosting and foraging areas, we observed an isolation by distance at the wider scale and lower but significant differentiation between closer populations (<50 km). All populations had a low level of relatedness and showed deviations from Hardy-Weinberg equilibrium and a low but significant inbreeding coefficient. The associated heterozygote deficiency was likely related to a Wahlund effect and to cryptic structures, reflecting social groups living in syntopy, both in roosting and foraging areas, with only limited admixture. Discrepancy between mitochondrial and nuclear markers suggests female philopatry and higher dispersal rates in males, associated with peripheral positions in the groups. Vampires are also the main neotropical reservoir for rabies virus, one of the main lethal pathogens for humans. Female social behaviors and trophallaxis may favor a rapid spread of virus to related and unrelated offspring and females. The high dispersal capacity of males may explain the wider circulation of viruses and the inefficacy of bat population controls. In such opportunistic species, gene connectivity should be considered for management decision making. Strategies such as culling could induce immigration of bats from neighboring colonies to fill vacant roosts and feeding areas, associated with the dispersal of viral strains

Phylogram of relationships among the Sycoecinae obtained from the analysis of the ClustalW alignment (combined dataset, without Gblocks cleaning, 5 partitions: mtDNA, <i>EF-1α</i>, ITS2, <i>RpL27a</i>, <i>mago</i><i>nashi</i>).

<p>Uppercase letters refer to clades discussed in the text. The new classification is indicated by colored bars on the right (yellow = oriental species, blue = afrotropical species). Nodes with likelihood bootstrap values < 70 have been collapsed. BP (> 70) and Bayesian posterior probabilities (> 0.90) are indicated at nodes. Illustrations of female habitus for the main clades are provided on the right. Host fig tree subsections are indicated between parentheses. Black boxes at nodes show cases of probable speciation on a single host <i>Ficus</i> species. </p

Cladograms of relationships among the Sycoecinae obtained from the MAFFT alignment of the combined dataset under three different alignment strategies and two partitioning schemes.

<p>The corresponding ML and Bayesian trees are given in Figures 1, S7-S12. Nodes with BP support < 70% have been collapsed and BP supports for main clades are indicated at nodes. Uppercase letters refer to clades discussed in the text (see also Figure 1). The dashed line indicates the only taxon with a conflicting position among trees (see text).</p

Per site phylogenetic informativeness profiles of the markers based on the MAFFT dataset (6 partitions).

<p>Uppercase letters refer to clades discussed in the text (see also Figures 1 & 2).</p

Phylogram of relationships among the Sycoecinae obtained from the analysis of the MAFFT alignment (combined dataset, without Gblocks cleaning, 6 partitions: mtDNAcodon1&2, mtDNAcodon3, <i>EF-1α</i>, ITS2, <i>RpL27a</i>, <i>mago</i><i>nashi</i>).

<p>Uppercase letters refer to clades discussed in the text. The new classification is indicated by colored bars on the right (yellow = oriental species, blue = afrotropical species). Nodes with likelihood bootstrap (BP) values < 70 have been collapsed. BP (> 70) and Bayesian posterior probabilities (> 0.90) are indicated at nodes. Illustrations of female habitus for the main clades are provided on the right. Host fig tree subsections are indicated between parentheses. Black boxes at nodes show cases of probable speciation on a single host <i>Ficus</i> species. </p

Compared phylogenies of the Afrotropical sycoecine fig wasps (this study) and their <i>Ficus</i> hosts

<p>(adapted from Rønsted et al. [94] and Renoult et al. [95]) .</p