Biology subjects

Jan, P.-L.

Publications and source records attributed to Jan, P.-L..

3 recordsLinked to original sources

bioRxiv2024

The geometry of gametic dispersal in a flying mammal, Rhinolophus hipposideros

Dispersal influences population and evolutionary dynamics, with effects that depend on the dispersal strategies through which gene flow occurs. In some species, mating partners move exclusively for mating, dispersing genes but not individuals. This is the case in many bat species, of which the lesser horseshoe bat (Rhinolophus hipposideros) shows a genetic structure at a fine spatial scale suggesting restricted dispersal. We investigated how natal and mating dispersal shape gene flow in this species in two metapopulations using paternity and population assignments. Half of the inferred paternities were intra-colonial and gave an estimate of the mean mating dispersal distance of around 11 km, explaining the observed genetic structure. Complete gametic dispersal distances were further estimated by combining natal with mating dispersal distances. The resulting gametic dispersal kernels showed a mean distance of around 20 km and a fat-tailed distribution typical of an excess of long-distance dispersal movements. It is the first time that natal and mating dispersal distances have been separately estimated and then combined in animals, documenting quantitatively how mating dispersal decorrelates gene and individual flows. It is important to consider this mechanism to explain dispersal evolution.

evolutionary biology↗

bioRxiv2019

Population-level sensitivity to landscape variables reflects individual-based habitat selection in a woodland bat species

Understanding the relationship between habitat quality and population dynamics is fundamental for long-term management and range predictions in ecology. However, habitat quality is generally only investigated at the individual scale, as it is the case for the lesser horseshoe bat (Rhinolophus hipposideros), a species of conservation concern. Using a statistical modelling approach and census data of 94 lesser horseshoe bat colonies located in Brittany (France), we analysed the effect of landscape composition and configuration on the demographic components of surveyed maternity colonies (i.e. colony size, fecundity and growth rate), and compared our result to those provided by individual-based studies. Our results validated that the landscape in a 500-meter buffer around colonies (core foraging area) is crucial for population size and dynamics, and confirmed the positive influence of broadleaved woodland proportion on bat colony size. We revealed a positive effect of lakeshores and riverbanks on colony size and growth rate, underlying the importance of these habitats for the long-term conservation of this non-migratory forest species. Importantly, our results refine previous knowledge concerning the threat posed by the intensification of human activities (e.g. urbanization, agriculture, habitat fragmentation), and highlight the negative effect of large and regular patches of artificial and crop lands and of open land patches shape complexity on all demographic variables investigated. While our results support the dependence of population dynamics and associated conservation management to individual behaviour and sensitivity, environmental responses differed between the population metrics investigated, showing that efficient range prediction will require to fully grasp the complexity of the interaction between landscape and the different population dynamic parameters.

ecology↗

bioRxiv2017

Effective population size and durability of plant resistances in the potato cyst nematode Globodera pallida

O_LIThe effective size of a population is the size of an ideal population which would drift at the same rate as the real population. The balance between selection and genetic drift depends on the population size expressed as the genetically effective population size (Ne), rather than the real numbers of individuals in the population (N).\nC_LIO_LIThe objectives of the present study were to estimate Ne in the potato cyst nematode Globodera pallida using artificial populations and to explore the link between Ne and the durability of plant resistances.\nC_LIO_LIUsing a temporal method on 24 independent pairs of initial and final populations, the median Ne was 58 individuals.\nC_LIO_LINe is commonly lower than N but in our case the Ne/N ratio was extremely low because G. pallida populations deviate in structure from the assumptions of the ideal population by having unequal sex-ratios, high levels of inbreeding and a high variance in family sizes. The consequences of a low Ne could be important for the control of phytoparasitic nematodes because G. pallida populations will have a low capacity to adapt to changing environments unless selection intensity is very strong, which could be greatly beneficial for long-term use of plant resistances.\nC_LI

evolutionary biology↗