Biology subjects

Kajtoch, L.

Publications and source records attributed to Kajtoch, L..

7 recordsLinked to original sources

bioRxiv2026

Metric-dependent genomic diversity reveals phylogenetic and ecological structure in saproxylic beetles

Abstract 1. Comparative studies can reach different conclusions when genomic-diversity metrics use different denominators. 2. We analysed standardized ddRAD-seq data from 759 individuals, 149 species-by-site population records and 26 saproxylic beetle species across eight Polish forest complexes. 3. Species identity and sampling hierarchy explained most population-level variation. Deciduous-associated species had higher variant-site expected heterozygosity than conifer-associated species. 4. All-position nucleotide diversity showed stable phylogenetic signal, whereas occurrence tier and exploratory forest-management and protection contrasts showed no consistent associations. 5. Genomic-diversity metrics are not interchangeable; comparative assessments should report their denominator and test lineage sensitivity.

evolutionary biology↗

bioRxiv2026

Beyond deadwood volume: structural heterogeneity and species-specific dispersal shape saproxylic beetle genetics

Many rare saproxylic (deadwood-dwelling) beetles are among Europes most threatened insects, yet the relative importance of local microhabitat quality versus broad-scale landscape connectivity in shaping their genetic integrity remains poorly understood. We evaluated environmental drivers for 13 saproxylic beetle species--rare old-growth specialists, common taxa, and economically significant pests--across eight major forest complexes in Poland, using double digest restriction-site associated DNA sequencing (ddRAD-seq) paired with plot-level structural inventories and estimated effective migration surfaces (EEMS) modelling. A beta generalized linear mixed model identified deadwood diversity as the only significant within-species predictor of observed heterozygosity ({beta} = 0.041, 95% CI 0.0227-0.0586, p < 10-); total deadwood volume, forest age, time since logging, stump density, and veteran tree density were not significant. Management-category contrasts in observed heterozygosity (Ho) and the inbreeding coefficient (Fis) were non-significant after Tukey adjustment. Predictor x ecological-tier interactions did not differ detectably between rare and common species for five of six structural predictors; time since last logging was the exception ({chi}{superscript 2} = 4.56, p = 0.033). EEMS patterns differed among species and fell into three broad groups: regional lineage barriers, asymmetrical corridors, and surfaces close to isolation- by-distance expectations. These results associate plot-level heterozygosity with deadwood diversity and show that regional gene-flow patterns cannot be generalised across saproxylic beetles. Conservation planning should therefore combine local deadwood restoration with species-specific assessment of landscape connectivity.

evolutionary biology↗

bioRxiv2025

Geography and forest naturalness as drivers of genetic diversity in saproxylic beetles

Understanding how geography and forest management shape genetic diversity is pivotal for the conservation of saproxylic beetles, the key indicators of forest ecosystem integrity. Using a multi-species Double Digest Restriction-site Associated DNA sequencing approach, we analyzed genome-scale SNP variation in 12 saproxylic beetle species (rare and common, incl. pests) differing in abundance, ecology, and mobility across central European forests, with respect to both geographic location and forest status. Analyses of distance-based redundancy test, molecular variance, and population structure consistently revealed that geography is the main determinant of genetic differentiation, with clear east-west clustering in several species. Forest status represented in four levels (commercial not protected, nature reserve, primeval not protected, and primeval protected) exerted a secondary but detectable effect in a subset of taxa, especially among rare and habitat-specialized species. For these species, populations from primeval protected sites showed distinct genetic structure compared to those from commercial stands. Our results highlight that regional connectivity, maintaining gene flow across a large spatial scale, should be prioritized in conservation planning, complemented by the protection of primeval forest refugia and the maintenance of structural complexity in commercial forests. By integrating high-resolution genomic data with geographical and management context, this study provides actionable insights into the processes shaping genetic structure in forest-dependent insects and underscores the importance of incorporating genetic monitoring into sustainable forest biodiversity management.

genetics↗

bioRxiv2025

To hybridise or not to hybridise? Systematic review and meta-analysis of woodpeckers

Hybridisation is a common phenomenon among birds in general. Woodpeckers (Picidae) are no exception, as approximately 20% of species are known to hybridise and for many others interspecific mating is suspected. However, the mechanisms and consequences (phenotypic and genetic) of hybridisation are known for only a fraction of woodpecker species. Here, we conduct a systematic review on the literature that deals with hybridisation in woodpeckers and use a meta-analytical approach to examine the available geographical and genetic data. According to available published data, the majority of woodpeckers that hybridise inhabit the Neotropics, followed by the Nearctic and the Palearctic. Hybridisation appears to be less common in the Afrotropic and Oriental regions. As expected, genetic distances are substantially lower between hybridising species pairs than between non hybridising congenerics. This implies that hybridisation is typical for "young" (sister) pairs of species, that typically have similarities in their respective reproductive biology, ecology and ethology, and thus had less time for genetic incompatibilities to build up. These similarities also explain the difficulties experienced in studies on hybrid woodpeckers, but these could be overcome by the use of modern techniques (remote sensing and/or citizen science combining with AI identification and genomic identification). As hybridisation plays a role in woodpecker evolution and ecology it should be considered when conservation policies for rare species are drafted.

evolutionary biology↗

bioRxiv2024

A review of co-occurrence and hybridization as neglected factors in studies of Syrianwoodpecker Dendrocopos syriacus and great spotted woodpecker Dendrocopos major

Some species of woodpecker (Picidae), such as in the genus Dendrocopos, are known to occasionally hybridize. The distribution, biology and ecology of the Syrian Woodpecker (D. syriacus) and the Great Spotted Woodpecker (D. major) are fairly well-known (less so in the case of Syrian), but these closely related species are seldom treated together in studies. This review summarizes the published data on these species in order to evaluate the omissions and inaccuracies in research and surveys on their sympatric populations. As research that deals with both species together is scant, the need to examine interactions, both antagonistic and hybridization, is advisable in order to properly understanding their ecology, ethology, breeding biology and demography.

zoology↗

bioRxiv2024

Meta-analysis of spatial genetic patterns among European saproxylic beetles - the influence of history and contemporary forest quality

The phylogeography of forest-dwelling species in Europe is well understood, although our knowledge regarding the genetics of saproxylic beetles remains insufficient. This knowledge gap extends to understanding the influence of both quaternary history and contemporary forest dynamics on population genetics. To fill this gap, we conducted a systematic review and meta-analysis of recent literature concerning saproxylic beetle taxa with available genetic data. We include both threatened and common species in our study which enabled us to generalize our findings to the whole saproxylic community. Results suggest a latitudinal decrease in diversity in most species, likely influenced by Pleistocene glaciation and subsequent population expansions from southern refugia. Additionally, we observed an east-west gradient in diversity, with threatened species exhibiting higher diversity towards the east. This may reflect historical forest dynamics and anthropogenic pressures, such as heavy wood logging in Western Europe. Similarly, we found a pattern along altitude, with populations in higher elevation forests, which are often more natural, exhibiting higher diversity. Furthermore, we identified distinct phylogenetic units or genetic clusters in southern Europe reflecting the distribution of glacial refugia. For some taxa, distinct units were also reported in eastern Europe where populations spread from Asian refugia. Central Europe showed a high number of phylogenetic units, although unique (private) clades or clusters were absent. Most likely it is an effect of the presence of beetles that originated from various refugia belonging to different phylogenetic units. This study brings insights into general phylogeographic patterns, which have previously been examined only for single representatives of saproxylic beetles. It should also help in the proper planning of conservation and management efforts of wood-dwelling beetles.

genetics↗

bioRxiv2022

Till evolution do us part: The diversity of symbiotic associations across populations of Philaenus spittlebugs

Symbiotic bacteria have played crucial roles in the evolution of sap-feeding insects and can strongly affect host function. However, their diversity and distribution within species are not well understood; we dont know to what extent environmental factors or associations with other species may affect microbial community profiles. Here, we sequenced host and bacterial marker gene amplicons to survey the bacterial community composition across multiple populations of Philaenus spittlebugs. Host mitochondrial sequence data confirmed morphology-based identification of 6 species and revealed two divergent clades of Philaenus spumarius. All of them hosted the primary symbiont Sulcia that was almost always accompanied by Sodalis. Interestingly, populations and individuals often differed in the presence of Sodalis sequence variants, suggestive of intra-genome 16S rRNA variant polymorphism combined with rapid genome evolution and/or recent additional infections or replacements of the co-primary symbiont. The prevalence of facultative endosymbionts, including Wolbachia, Rickettsia, and Spiroplasma, varied among populations. Notably, COI amplicon data also showed that nearly a quarter of P. spumarius were infected by parasitoid flies (Verralia aucta). One of the Wolbachia OTUs was exclusively present in Verralia-parasitized specimens, suggestive of parasitoids as their source and highlighting the utility of host gene amplicon sequencing in microbiome studies.

ecology↗