Nikolett Ujhegyi - Academia.edu (original) (raw)

Papers by Nikolett Ujhegyi

Environmentally sensitive sex determination may help organisms adapt to environmental change but ... more Environmentally sensitive sex determination may help organisms adapt to environmental change but also makes them vulnerable to anthropogenic stressors, with diverse consequences for population dynamics and evolution. The mechanisms translating environmental stimuli to sex are controversial: although several fish experiments supported the mediator role of glucocorticoid hormones, results on some reptiles challenged it. We tested this hypothesis in amphibians by investigating the effect of corticosterone on sex determination in agile frogs (Rana dalmatina). This species is liable to environmental sex reversal whereby genetic females develop into phenotypic males. After exposing tadpoles during sex determination to waterborne corticosterone, the proportion of genetic females with testes or ovotestes increased from 11% to up to 32% at 3 out of 4 concentrations. These differences were not statistically significant except for the group treated with 10 nM corticosterone, and there was no m...

Individual data on: - Free-living adult common toads: catching site, habitat type, sexua... more Individual data on: - Free-living adult common toads: catching site, habitat type, sexual phenotype and genotype - Juvenile common toads raised in a common-garden experiment: family, treatment, site of origin, habitat type and sex (phenotype and genotype combined)

This dataset contains data on genetic (GenoSex) and phenotypic (PhenoSex) sex, and a variety of m... more This dataset contains data on genetic (GenoSex) and phenotypic (PhenoSex) sex, and a variety of morphology measurements of 125 laboratory-raised and 162 wild-caught agile frog (Rana dalmatina) individuals from Hungary.

Extreme temperatures during heat waves can induce mass-mortality events, but can also exert suble... more Extreme temperatures during heat waves can induce mass-mortality events, but can also exert sublethal negative effects by compromising life-history traits and derailing sexual development. Ectothermic animals may, however, also benefit from increased temperatures via enhanced physiological performance and the suppression of cold-adapted pathogens. Therefore, it is crucial to address how the intensity and timing of naturally occurring or human-induced heat waves affect life-history traits and sexual development in amphibians, to predict future effects of climate change and to minimise risks arising from the application of elevated temperature in disease mitigation. We raised agile frog (Rana dalmatina) and common toad (Bufo bufo) tadpoles at 19 °C and exposed them to a simulated heat wave of 28 or 30 °C for six days during one of three ontogenetic periods (early, mid or late larval development). In agile frogs, exposure to 30 °C during early larval development increased mortality. Re...

Az Europai Unio szamos tagorszagaban hoztak letre agrar-kornyezetgazdalkodasi programokat, melyek... more Az Europai Unio szamos tagorszagaban hoztak letre agrar-kornyezetgazdalkodasi programokat, melyek az intenziv mezőgazdasag karos hatasait hivatottak mersekelni. Eredmenyesseguket komoly szakmai vita kiseri, mely pusztan gazdasagi jelentőseguk miatt is kiemelt fontossaggal bir. Hazankban 2014-ben zarult le az Agrar-kornyezetgazdalkodasi Tamogatasi Rendszer (AKG) 5 eves ciklusa. Ennek aprovadfajokra gyakorolt hatasanak felmeresevel a Vadvilag Megőrzesi Intezetet bizta meg a Nemzeti Elelmiszerlanc-biztonsagi Hivatal. Az aprovadfajok – kiemelten a mezei nyul (Lepus europaeus) – kivalo bioindikatorai a hasonlo programoknak, illetve a mezei okoszisztemaknak, az extenziv gazdalkodasi modoknak. Allomanyvaltozasuk szamos egyeb, sok esetben veszelyeztetett, nehezen megfigyelhető faj allomanyalakulasat is jelzi. Az AKG es az aprovadallomanyok kapcsolatat kis es nagy terleptekű elemzesekkel is vizsgaltuk, előbbiek magukba foglaltak a szeles korben alkalmazott allomanybecslesi, terulethasznalat-...

Acta Zoologica Academiae Scientiarum Hungaricae, 2021

The goal of many agri-environment schemes (AES) is to increase biodiversity in agroecosystems. AE... more The goal of many agri-environment schemes (AES) is to increase biodiversity in agroecosystems. AES effects are often measured on invertebrates and birds; mammals as indicator species are infrequently targets of such researches. Our goal was to evaluate the local-scale effects of the Hungarian Agri-Environmental Measures (AEM) on the European brown hare (Lepus europaeus), which shows decreasing population trends across Europe. We compared hare abundances and their dropping numbers in AEM and control agricultural arable and grassland fields of 17 game management units in two seasons. We also examined the quality of arable fields based on their margin width and vegetation cover. We found that margin quality was higher in AEM than in the control fields. Control grasslands had higher vegetation quality than the AEM grasslands. We found a significant difference in hare counts between AEM and control arable fields in spring but no difference in autumn. The dropping densities did not differ...

Monitoring of presence or estimation of density of carnivores using invasive or disruptive method... more Monitoring of presence or estimation of density of carnivores using invasive or disruptive methods, like hunting, life-catching or visual observation can bias research results and might be controversial when studying threatened species. Therefore, non-invasive approaches become increasingly used in the last few decades. Hair collection is one among many useful indirect methods. Knowledge on efficient hair-traps on European carnivore species is limited. Yet, hair-traps have been reported as huge success when tested in enclosures but often are challenging to use in natural environments. Our aim was to compile a comprehensive literature review on hair traps and attractants in order to find out what techniques could be used by field experts. We have found that practical application of some techniques might be hard when studying edge populations but with hair-collection methods additional information can be gathered relatively easily in species core area where animals are abundant. We ha...

Science of The Total Environment, 2018

Many chemical pollutants have endocrine disrupting effects which can cause lifelong reproductive ... more Many chemical pollutants have endocrine disrupting effects which can cause lifelong reproductive abnormalities in animals. Amphibians are the most threatened group of vertebrates, but there is little information on the nature and quantity of pollutants occurring in typical amphibian breeding habitats and on the reproductive capacities of amphibian populations inhabiting polluted areas. In this study we investigated the occurrence and concentrations of endocrine disrupting chemicals in the water and sediment of under-studied amphibian breeding habitats in natural, agricultural and urbanized landscapes. Also, we captured reproductively active common toads (Bufo bufo) from these habitats and let them spawn in a 'common garden' to assess among-population differences in reproductive capacity. Across 12 ponds, we detected 41 out of the 133 contaminants we screened for, with unusually high concentrations of glyphosate and carbamazepine. Levels of polycyclic aromatic hydrocarbons, nonylphenol and bisphenol-A increased with urban land use, whereas levels of organochlorine and triazine pesticides and sex hormones increased with agricultural land use. Toads from all habitats had high fecundity, fertilization rate and offspring viability, but the F1 generation originating from agricultural and urban ponds had reduced development rates and lower body mass both as larvae and as juveniles. Females with small clutch mass produced thicker jelly coat around their eggs if they originated from agricultural and urban ponds compared with natural ponds. These results suggest that the observed pollution levels did not compromise reproductive potential in toads, but individual 3 fitness and population viability may be reduced in anthropogenically influenced habitats, perhaps due to transgenerational effects and/or costs of tolerance to chemical contaminants.

Összefoglalás: számos faj alkalmazkodott jól az emberi településekhez és a városi környezethez. A... more Összefoglalás: számos faj alkalmazkodott jól az emberi településekhez és a városi környezethez. A városi élő-helyek biodiverzitásának vizsgálata többek között a ritka vagy rejtőzködő fajok miatt alapvetően nehéz feladat. A nehezen vizsgálható fajok esetében különösen fontossá válnak az úgynevezett nem-invazív (noninvasive) vizsgálati módszerek, amelyek az állat megfogása, jelölése nélkül juttatnak minket a jelenlétükhöz kapcsolódó információkhoz. Ilyen módszerekkel fontos adatok szerezhetőek az emlősállatok szőreiből is, mivel azok a határozási módszertől függően nemzetségre, fajra, vagy akár egyedre vonatkozó információkat is adhatnak. Vizsgálatunkban a gyűjtött szőrszálak makroszkopikus és mikroszkopikus határozását választottuk. A mak-roszkopikus tulajdonságokon kívül egy szőrnek négy fontos mikroszkopikus tulajdonságát vettük figyelembe a határozásnál; a kutikula mintázatát az alnyélen (1) és a legvastagabb ponton (2), a medulla mintázatát a legvas-tagabb szakaszon olajos festés...

Several things can influence us when our opinion is being shaped. Media, traditions and superstit... more Several things can influence us when our opinion is being shaped. Media, traditions and superstitions can be harmful factors of influence. The most receptive and vulnerable age group is the 8-14 year old teenagers. During this period outside impacts are playing decisive role to shape their personality (these effects can predict what kind of person they will become). We have done an attitude survey in this age group. Our question was as follows: Can significant difference be detected between "treated" school group and "control" school group due to the dissemination? A paper-based questionnaire was used, about bats and what children think about bats. The questionnaire included 22 items based on the works of ADDAMS & LINDSEY (2009) and LETENYEI & NAGY (2007). The questionnaires were summarized as "treated" and "control" groups, then Microsoft Excel was used to perform Chi-square tests. From 22 questions only four were shown significant difference and three differences out of four were shown in the control group. The wrong answers percentage was increased all the three times. Treated group was shown strong significant difference (p=0,001) in one question ("How do you relate to bats?"). In this case the positive attitude has been increased due to the dissemination. Since there is not any significant difference in the vast majority of these questions (before and after the dissemination), the effect of the dissemination is questionable. Presumably, there will not be increase in the population's knowledge, but the emotional attitude can be changed with dissemination.

With noninvasive methods we can avoid direct contact with animals, because of this, researchers' ... more With noninvasive methods we can avoid direct contact with animals, because of this, researchers' presence will not bias the results of the survey and animals can avoid stressful situations. The use of noninvasive techniques probably dates back to the origin of humans, the knowledge on traces and scats can be considered as noninvasive methods, but we can gather useful information from mammalian hairs too. A hair can be a useful data source to gather infromation on certain predators' diet (ex. scat analysis, prey remains) or to receive some basic faunistical data on a given area (ex. birdnest analysis), but it can be a good tool for forensic science too. There are certain features of a hair that can be used for identification, such as lenght, shape, color (macroscopic), medulla pattern with and without oil preparation, and cuticula impression in gelatin (microscopic). These features were examined by a light microscope (400x magnification). Hair samples from 11 predator species kept in safari park-occured in Hungary were studied. Hair was collected from 4 body region individually (dorsal, lateral, abdominal, snout). Thus 44 independent, anonym samples were sent to three experts to identify the species by the hair. Four species were identyfied with success over 50% (Brown bear 75%, European badger 67%, Lynx 58%, Raccoon dog 58%) in total. Raccoon and grey wolf were identyfied in the least range (17%-17%). Regarding the different body parts, there were significant differences in identifying hair samples with success of certain species. It was easier to identify the species by dorsal cover hair (61%) than by the lateral hair (55%). The rate of success by examining hair from the abdomen and snout is only 21% and 24%. Unsuccessful identification was 9 out of 44 samples (hair from abdomen in 5 cases, hair from snout in 4 cases). Researchs was supported "Sustainable Conservation on Hungarian Natura 2000 Sites" (registration number SH/4/8) Swiss-Hungarian partnership program. Report was supported by the Ministry of Human Resources. (Research Faculty) (registration number: 7 629-24/2013/TUDPOL).

Tudományos Ismeretterjesztő Társulat, May 10, 2020

Frontiers in Ecology and Evolution

Sex reversal is a mismatch between genetic sex (sex chromosomes) and phenotypic sex (reproductive... more Sex reversal is a mismatch between genetic sex (sex chromosomes) and phenotypic sex (reproductive organs and secondary sexual traits). It can be induced in various ectothermic vertebrates by environmental perturbations, such as extreme temperatures or chemical pollution, experienced during embryonic or larval development. Theoretical studies and recent empirical evidence suggest that sex reversal may be widespread in nature and may impact individual fitness and population dynamics. So far, however, little is known about the performance of sex-reversed individuals in fitness-related traits compared to conspecifics whose phenotypic sex is concordant with their genetic sex. Using a novel molecular marker set for diagnosing genetic sex in agile frogs (Rana dalmatina), we investigated fitness-related traits in larvae and juveniles that underwent spontaneous female-to-male sex reversal in the laboratory. We found only a few differences in early life growth, development, and larval behavio...

The widespread application of pesticides makes it important to understand the impacts of these ch... more The widespread application of pesticides makes it important to understand the impacts of these chemicals on wildlife populations. Chlorpyrifos is an organophosphate insecticide which can affect the development and behavior of aquatic organisms and may thereby alter predator-prey interactions. To investigate how environmentally relevant, sublethal concentrations of chlorpyrifos affect anti-predator behavior and larval development of the agile frog (Rana dalmatina), we exposed tadpoles to one of three concentrations (0, 0.5 and 5 μg chlorpyrifos / L) either for a brief period of three days (acute exposure) or throughout larval development (chronic exposure). We observed tadpole activity and space use in the presence or absence of chemical cues of predatory fish. We also assessed mortality, time to metamorphosis, mass at metamorphosis, brain morphology and sex ratio. We found that tadpoles chronically exposed to 5 μg/L chlorpyrifos swam distances that were longer by more than 20 % and ...

Anthropogenic environmental changes are affecting biodiversity and microevolution worldwide. Ecto... more Anthropogenic environmental changes are affecting biodiversity and microevolution worldwide. Ectothermic vertebrates are especially vulnerable, since their sexual development can be disrupted by environmental changes, which can cause sex reversal, a mismatch between genetic and phenotypic sex, potentially leading to sex-ratio distortion and population decline. Despite these implications, we have scarce empirical knowledge on the incidence of sex reversal in nature. Populations in anthropogenic environments may experience sex reversal more frequently, or alternatively, they may adapt to resist sex reversal. To test these alternative hypotheses, we developed PCR-based genetic sex markers for the common toad (Bufo bufo). We assessed 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 estrogenic pollutants in a common-garden experiment. We found negligible sex-reversal fre...

Acta Zoologica Academiae Scientiarum Hungaricae, 2021

Science of The Total Environment, 2018

Tudományos Ismeretterjesztő Társulat, May 10, 2020

Frontiers in Ecology and Evolution