Strong isolation by distance among local populations of an endangered butterfly species (Euphydryas aurinia)

Abstract

The marsh fritillary (Euphydryas aurinia) is a critically endangered butterfly species in Denmark known to be particularly vulnerable to habitat fragmentation due to its poor dispersal capacity. We identified and genotyped 318 novel SNP loci across 273 individuals obtained from 10 small and fragmented populations in Denmark using a genotyping‐by‐sequencing (GBS) approach to investigate its population genetic structure. Our results showed clear genetic substructuring and highly significant population differentiation based on genetic divergence (FST) among the 10 populations. The populations clustered in three overall clusters, and due to further substructuring among these, it was possible to clearly distinguish six clusters in total. We found highly significant deviations from Hardy–Weinberg equilibrium due to heterozygote deficiency within every population investigated, which indicates substructuring and/or inbreeding (due to mating among closely related individuals). The stringent filtering procedure that we have applied to our genotype quality could have overestimated the heterozygote deficiency and the degree of substructuring of our clusters but is allowing relative comparisons of the genetic parameters among clusters. Genetic divergence increased significantly with geographic distance, suggesting limited gene flow at spatial scales comparable to the dispersal distance of individual butterflies and strong isolation by distance. Altogether, our results clearly indicate that the marsh fritillary populations are genetically isolated. Further, our results highlight that the relevant spatial scale for conservation of rare, low mobile species may be smaller than previously anticipated.

Considerable genetic diversity and structure despite narrow endemism and limited ecological specialization in the Hayden's ringlet, Coenonympha haydenii

“…Despite the clear patterns of genetic structure present in this species, F ST values between populations of Hayden's ringlets were low to moderate. The scale of differentiation we observed is consistent with fine‐ to moderate‐scale genetic population structure ( F ST between 0.01 and 0.2) seen in other non‐migratory butterfly species (Hinojosa et al., 2023; Pertoldi et al., 2021; Talla et al., 2019, 2023), and on average greater than in migratory species like monarchs () (Talla et al., 2020). While the F ST values we observed may be considered low in other groups of organisms, in many cases F ST values between nominal species of butterflies are not considerably greater than what we found within populations of the Hayden's ringlet (i.e.…”

Microsatellites for butterfly conservation: historical challenges, current relevance, and a guide to implementation

“…This approach has been implemented for a British population of the Marsh Fritillary, Euphydryas aurinia (Rottemburg, 1775) (Nymphalidae) (Table 1). The species is a Eurasian butterfly with declining populations across its range (Petenian et al, 2005) and multiple studies have found metapopulation structure in E. aurinia (Warren, 1994;Anthes et al, 2003;Davis et al, 2021;Junker et al, 2021;Pertoldi et al, 2021;Konvicka et al, 2023). Population sizes fluctuate as a result of pressure from parasitoid wasps (Porter, 1983).…”

Evolutionary genomics: Insights from the invasive European starlings

“…Strong subpopulation structure and recent range expansion may confound local signatures of adaptation, and therefore analytical approaches should take this into account (e.g., Stuart et al, 2022d ; 2022c ). The impact of separate introduction sites or range expansions on population-wide genetic variation is something that may need to be considered not just within invasive populations, but during genomic studies on non-invasive populations (e.g., Drury et al, 2017 ; Drinan et al, 2018 ; Pertoldi et al, 2021 ), and species reintroductions (e.g., Kaulfuss & Reisch 2017 ; Dincă et al, 2018 ; Mims et al, 2019 ).…”