Genetic structure confirms female-biased natal dispersal in the White-tailed Eagle population of the Carpathian Basin

Individuals can avoid inbreeding or competition with kin via long-distance natal dispersal. On the other hand, staying close to the well-known natal area may be a safer choice with respect to recruiting opportunities, reproductive success and the individual’s survival probability as well. Natal dispersal strategy often differs between sexes, being generally female-biased in birds. We explored if the Carpathian Basin White-tailed Eagle population shows fine scale genetic structure and if it does, what is the extent of philopatry in the two sexes. We furthermore investigated sex bias in natal dispersal distance inferred from spatial distributions of genetically close relative breeding females and males. Spatial autocorrelation analyses failed to find fine-scale genetic structure, despite the species being known to be philopatric. Pairwise breeding distances of close relatives showed female bias according to Wilcoxon rank sum test. The median distance of two close relative females was 136 km, while it was only 38 km in males. Since White-tailed Eagles are known to be faithful to their breeding territory, we assumed that the breeding distance between an individual and its parents refers to the individual’s natal dispersal distance. Due to the same reason, the breeding distance of two siblings should also be related to their individual dispersal distances from their shared natal area. Therefore, we argue that the difference we found between sexes in pairwise breeding distances of close relatives stands for a female-biased natal dispersal. This bias may be a consequence of the species’ breeding strategy, and it decreases the inbreeding probability as well

Endocrine disruptors in breeding ponds and reproductive health of toads in agricultural, urban and natural landscapes

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Climate-driven shifts in adult sex ratios via sex reversals: the type of sex determination matters

Sex reversals whereby individuals of one genetic sex develop the phenotype of the opposite sex occur in ectothermic vertebrates with genetic sex-determination systems that are sensitive to extreme temperatures during sexual differentiation. Recent rises in global temperatures have led researchers to predict that sex reversals will become more common, resulting in the distortion of many populations' sex ratios. However, it is unclear whether susceptibility to climate-driven sex-ratio shifts depends on the type of sex determination that varies across species. First, we show here using individual-based theoretical models that XX/XY (male-heterogametic) and ZZ/ZW (female-heterogametic) sex-determination systems can respond differentially to temperature-induced sex reversals. Interestingly, the impacts of climate warming on adult sex ratio (ASR) depend on the effects of both genotypic and phenotypic sex on survival and reproduction. Second, we analyse the temporal changes of ASR in natural amphibian populations using data from the literature, and find that ASR shifted towards males in ZZ/ZW species over the past 60 years, but did not change significantly in XX/XY species. Our results highlight the fact that we need a better understanding of the interactions between genetic and environmental sex-determining mechanisms to predict the responses of ectotherms to climate change and the associated extinction risks. This article is part of the themed issue ‘Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies’.</jats:p

Novel genetic sex markers reveal unexpected lack of, and similar susceptibility to, sex reversal in free-living common toads in both natural and anthropogenic habitats

Anthropogenic environmental changes are affecting biodiversity and microevolution worldwide. Ectothermic vertebrates are especially vulnerable because environmental changes can disrupt their sexual development and cause sex reversal, a mismatch between genetic and phenotypic sex. This can potentially lead to sex‐ratio distortion and population decline. Despite these implications, there is scarce empirical knowledge on the incidence of sex reversal in nature. Populations in anthropogenic environments may be exposed to sex‐reversing stimuli more frequently, which may lead to higher sex‐reversal rate or, alternatively, these populations may adapt to resist sex reversal. We developed PCR‐based genetic sex markers for the common toad (Bufo bufo) to assess the prevalence of sex reversal in wild populations living in natural, agricultural and urban habitats, and the susceptibility of the same populations to two ubiquitous oestrogenic pollutants in a common garden experiment. We found negligible sex‐reversal frequency in free‐living adults despite the presence of various endocrine‐disrupting pollutants in their breeding ponds. Individuals from different habitat types showed similar susceptibility to sex reversal in the laboratory: all genetic males developed female phenotype when exposed to 1 µg L(−1) 17α‐ethinylestradiol (EE2) during larval development, whereas no sex reversal occurred in response to 1 ng L(−1) EE2 and a glyphosate‐based herbicide with 3 µg L(−1) or 3 mg L(−1) glyphosate. The latter results do not support that populations in anthropogenic habitats would have either increased propensity for or higher tolerance to chemically induced sex reversal. Thus, the extremely low sex‐reversal frequency in wild toads compared to other ectothermic vertebrates studied before might indicate idiosyncratic, potentially species‐specific resistance to sex reversal

A Kárpát-medence Rétisas-populációjának (Haliaeetus Albicilla) filogeográfiai és populáció-genetikai vizsgálata : Szakdolg.

The white-tailed eagle (Haliaeetus albicilla, Linnaeus 1758) is a large raptor species, whose southernmost population is located in the Carpathian Basin. After a drastic decrease in the early 20th century, from the 1970's the European population have started to recover. In the 1970s, the total Hungarian breeding population was estimated 10-12 pairs, all inhabiting the South Transdanuibian region, with presumably no breeding birds in the Tiszántúl region. Nowadays, population census of the country is more than 220 breeding pairs, with abundant territories also nearby the Tisza river. Phylogeography throughout the distribution range of the species was studied using the mitochondrial DNA control region, revealing two distinct haplogroups with predominantly eastern or western distribution. According to this, the species is suggested to have survived the last glacial event in two main refugia, probably located in Central and Western Eurasia. This distribution pattern was later refined with involving samples from the breeding populations of Central Europe, describing several new haplotypes from this region. However, phylogography and populaton structure of the population inhabiting the Carpathian Basin was not studied until now. In this study, we attempted (1) to reveal phylogeographic relations of the white-tailed eagle population inhabiting the Carpathian Basin in relation to other populations in Europe, using a mtDNA control region fragment (16 samples), and (2) to highlight origin of the breeding population in the Tisza region. According to our two main hypothesis, eagles in this breeding area may originate (I) from wintering birds that arrivied from the Northern European populations and settled in the area, or (II) from dispersing birds of the breeding areas located in the southern part of the Carpathian Basin. To answer this question, we studied genetic structure and gene-flow between southwestern and Tisza region breeding areas using nine nuclear microsatellite loci, involving 104 nestling from different localities of the Carpathian Basin. As DNA source, we used plucked feathers of nestling birds, Our results showed a high mixture of haplotypes in the Carpathian Basin, with haplotypes that are present in Asian, North- and Central-European populations as well. Moreover, we found no genetic differentiation between southwestern and Tisza region, suggesting that the white-tailed eagles inhabiting the Carpathian Basin belong to one single population. According to these results, birds breeding in the Tisza region can be originated from the southwestern breeding areaa of the Carpathian Basin

A környezeti tényezők DNS-re gyakorolt degradációs hatásainak modellezése madártollakon

A madárgenetikai vizsgálatok során egyre inkább elterjedt nem-invazív mintavételi eljárás a vedlett tollak terepen történő összegyűjtése. Ezek a tollak azonban a legkülönbözőbb helyekről (cserjék alól, lombozatról, nedves talajról, vagy éppen száraz sziklákról) kerülhetnek elő, és számos környezeti hatás érheti őket. Összeállítottunk egy kísérletet, amelyben külön vizsgáltuk a magas relatív páratartalom és magas hőmérséklet, az alacsony relatív páratartalom melletti magas hőmérséklet, valamint a napsugárzás hatásait a tollakból kivonható DNS-re. A kísérlethez 2010-ben és 2011-ben nyári lúd (Anser anser) tollakat (kettes és hármas kézevezők) téptünk a vedlési időszak környékén, hogy azok állapota megközelítse a természetes úton vedlett tollakét, de ne érje azokat ismeretlen környezeti hatás. A kísérlet során összesen 112, kezelésenként 16 darab tollat vizsgáltam meg. A DNS kinyerése a tollakból a felső köldök kimetszésével történt. A DNS fragmentáltságának (károsodásának) mértékét különböző hosszúságú (151 bp, 300 bp, 500 bp és 985 bp) nukleáris DNS szakaszok PCR-rel történő felszaporításával vizsgáltam. Eredményeink azt mutatták, hogy a vedlett tollakból kivonható DNS minőségét leginkább a magas relatív páratartalom mellett elszaporodó mikroorganizmusok veszélyeztethetik, hosszabb távon pedig az erős napsugárzás is jelentős károsodást okozhat.Collecting the shed feathers is a more and more wide-spread non-invasive sampling method used in the avian genetic studies. However, these feathers can be found on different types of fields (under the bushes, in the leaves, on the wet ground, or on dry rocks), and they can be disposed to numerous environmental effects. We have created an experiment, in wich we investigated the effects of high relative humidity combined with high temperature, low relative humiditiy combined with high temperature and the effects of the ray of sunlight on the DNA extracted from the feathers. For the experiment, we plucked feathers (second and third primaries) in 2010 and 2011 from greylag geese (Anser anser) during their moulting season, so the condition of the feathers was similar to those which were moulted naturally, and by doing so we avoided unknown environmental effects. I examined 112 feathers altogether, 16 per treatment. The extraction of the DNA was performed by cutting out the superior umbilicus. I studied the fragmentation of the DNA by using the PCR to multiply nuclear DNA sequences with different lenght (151 bp, 300 bp, 500 bp and 985 bp). The results showed that the DNA extracted from the shed feathers is most likely endangered by the microorganisms, that grow in high humidity. In the long-term, the ray of sunlight can also do considerable damage

Evolutionary and demographic consequences of temperature-induced masculinization under climate warming: the effects of mate choice

Abstract Background One of the dangers of global climate change to wildlife is distorting sex ratios by temperature-induced sex reversals in populations where sex determination is not exclusively genetic, potentially leading to population collapse and/or sex-determination system transformation. Here we introduce a new concept on how these outcomes may be altered by mate choice if sex-chromosome-linked phenotypic traits allow females to choose between normal and sex-reversed (genetically female) males. Results We developed a theoretical model to investigate if an already existing autosomal allele encoding preference for sex-reversed males would spread and affect demographic and evolutionary processes under climate warming. We found that preference for sex-reversed males (1) more likely spread in ZW/ZZ than in XX/XY sex-determination systems, (2) in populations starting with ZW/ZZ system, it significantly hastened the transitions between different sex-determination systems and maintained more balanced adult sex ratio for longer compared to populations where all females preferred normal males; and (3) in ZW/ZZ systems with low but non-zero viability of WW individuals, a widespread preference for sex-reversed males saved the populations from early extinction. Conclusions Our results suggest that climate change may affect the evolution of mate choice, which in turn may influence the evolution of sex-determination systems, sex ratios, and thereby adaptive potential and population persistence. These findings show that preferences for sex-linked traits have special implications in species with sex reversal, highlighting the need for empirical research on the role of sex reversal in mate choice