Biology subjects

Leuchtmann, M.

Publications and source records attributed to Leuchtmann, M..

5 recordsLinked to original sources

bioRxiv2026

Fine-scale maternal structure and high nuclear connectivity in the French populations of the Geoffroy's Bat (Myotis emarginatus)

The Geoffroy's bat (Myotis emarginatus) is a sedentary species increasingly threatened by habitat alteration. Here, we assessed genetic diversity and population structure in 760 individuals from 18 French maternity colonies using 34 microsatellite markers and mitochondrial D-loop sequences. Mitochondrial data revealed subtle regional structure, consistent with female philopatry, and a broader phylogeographic split between Western Europe and the Greater Middle East, reflecting historical isolation. In contrast, microsatellites showed high nuclear diversity and minimal population structure across France, with weak isolation by distance and kin clustering, indicating extensive male-mediated gene flow. Moreover, demographic inference suggested population stability, consistent with both marker types. This nuclear homogeneity and demographic stability are strikingly similar to the patterns observed in Rhinolophus ferrumequinum populations sampled at the same colonies, suggesting that reproductive aggregation can maintain connectivity even in sedentary species. Overall, M. emarginatus functions as a largely connected population at the national scale, although localized maternal lineages suggest the presence of functional phylopatric units around key maternity sites that warrant protection. Future genome-wide studies could refine conservation strategies by integrating fine-scale female philopatry with male-mediated connectivity.

genetics↗

bioRxiv2020

eDNA metabarcoding reveals a core and secondary diets of the greater horseshoe bat with strong spatio-temporal plasticity

Dietary plasticity is an important issue for conservation biology as it may be essential for species to cope with environmental changes. However, this process still remains scarcely addressed in the literature, potentially because diet studies have long been constrained by methodological limits. The advent of molecular approaches now makes it possible to get a precise picture of diet and its plasticity, even for endangered and elusive species. Here we focused on the greater horseshoe bat (Rhinolophus ferrumequinum) in Western France, where this insectivorous species has been classified as Vulnerable on the Regional Red List in 2016. We applied an eDNA metabarcoding approach on 1986 fecal samples collected in six maternity colonies at three sampling dates. We described its diet and investigated whether the landscape surrounding colonies and the different phases of the maternity cycle influenced the diversity and the composition of this diet. We showed that R. ferrumequinum feed on a highly more diverse spectrum of prey than expected from previous studies, therefore highlighting how eDNA metabarcoding can help improving diet knowledge of a flying elusive endangered species. Our approach also revealed that R. ferrumequinum diet is composed of two distinct features: the core diet consisting in a few preferred taxa shared by all the colonies (25% of the occurrences) and the secondary diet consisting in numerous rare prey that were highly different between colonies and sampling dates (75% of the occurrences). Energetic needs and constraints associated with the greater horseshoe bat life-cycle, as well as insect phenology and landscape features, strongly influenced the diversity and composition of both the core and whole diets. Further research should now explore the relationships between R. ferrumequinum dietary plasticity and fitness, to better assess the impact of core prey decline on R. ferrumequinum populations viability.

ecology↗

bioRxiv2019

In silico and empirical evaluation of twelve COI & 16S metabarcoding primer sets for insectivorous diet analyses

This last decade, environmental DNA metabarcoding approaches have been developed and improved to minimize biological and technical biases; some challenges, however, remain, as the design of primers. Here we have performed a comprehensive assessment of ten COI and two 16S primer sets. We have combined in silico, in vivo-mock community of 33 arthropod taxa from 16 orders and guano analyses to identify primer sets that should maximize arthropod detection and taxonomic identification, whilst identifying bat species and minimizing labour time and cost. We have focused on two insectivorous bat species living in mixed-colonies, the greater horseshoe bat (Rhinolophus ferrumequinum) and Geoffroys bat (Myotis emarginatus). We have found that the level of primer degeneracy is the main factor influencing arthropod detection for in silico and mock community analyses, while the amplicon length is critical for the detection of arthropods from degraded DNA samples. Our results confirm the importance of performing predator detection and taxonomic identification, simultaneously with arthropod sequencing, as faeces samples can be contaminated by different insectivorous species. Moreover, amplifying bat DNA does not affect the primers capacity to detect arthropods. We therefore recommend the systematic simultaneous identification of predator and prey. Finally, we evidenced that one third of the prey occurrences are unreliable and probably not of primary interest in diet studies, which might decrease the relevance of combining several primer sets instead of using one efficient primer set. In conclusion, this study provides general criteria enabling the selection of primers whilst considering different scientific and methodological constraints.

molecular biology↗

bioRxiv2019

Integrating population genetics to define conservation units from the core to the edge of Rhinolophus ferrumequinum western range

The greater horseshoe bat (Rhinolophus ferrumequinum) is among the most widespread bat species in Europe but it has experienced severe declines, especially in Northern Europe. This species is listed Near Threatened in the European IUCN Red List of Threatened Animals and it is considered to be highly sensitive to human activities and particularly to habitat fragmentation. Therefore, understanding the population boundaries and demographic history of populations of this species is of primary importance to assess relevant conservation strategies. In this study, we used 17 microsatellite markers to assess the genetic diversity, the genetic structure and the demographic history of R. ferrumequinum colonies in the Western European part of its distribution. We found high levels of genetic diversity and large population size on the European mainland and lower estimates in England and Northern France. Analyses of clustering and isolation by distance showed a barrier effect of the Channel and potentially of the Mediterranean Sea on R. ferrumequinum bat dispersal. Conversely, we could not reveal any gene flow disruption from both sides of the Western Pyrenees. These results provide important information to improve the delineation of R. ferrumequinum management units in its western range. We suggest that a large management unit corresponding to the European mainland population must be considered. Particular attention should be given to mating territories as they seem to play a key role in maintaining the high levels of genetic mixing between colonies. Smaller management units corresponding to English and Northern France colonies must also be implemented. These insular or peripheral colonies could be at higher risk of extinction in a near future.

evolutionary biology↗

bioRxiv2017

Metabarcoding for the parallel identification of several hundred predators and their preys: application to bat species diet analysis

Assessing diet variability is of main importance to better understand the biology of bats and design conservation strategies. Although the advent of metabarcoding has facilitated such analyses, this approach does not come without challenges. Biases may occur throughout the whole experiment, from fieldwork to biostatistics, resulting in the detection of false negatives, false positives or low taxonomic resolution. We detail a rigorous metabarcoding approach based on a short COI minibarcode and two-step PCR protocol enabling the all at once taxonomic identification of bats and their arthropod preys for several hundreds of samples. Our study includes faecal pellets collected in France from 357 bats representing 16 species, as well as insect mock communities that mimic bat meals of known composition, negative and positive controls. All samples were analysed using three replicates. We compare the efficiency of DNA extraction methods and we evaluate the effectiveness of our protocol using identification success, taxonomic resolution, sensitivity, and amplification biases. Our parallel identification strategy of predators and preys reduces the risk of mis-assigning preys to wrong predators and decreases the number of molecular steps. Controls and replicates enable to filter the data and limit the risk of false positives, hence guaranteeing high confidence results for both prey occurrence and bat species identification. We validate 551 COI variants from arthropod including 18 orders, 117 family, 282 genus and 290 species. Our method therefore provides a rapid, resolutive and cost-effective screening tool for addressing evolutionary ecological issues or developing chirosurveillance and conservation strategies.

ecology↗