Similarity of Microplastic Characteristics between Amphibian Larvae and Their Aquatic Environment.

Microplastics, pervasive environmental pollutants, are found across various ecosystems, including small inland water bodies. They are reported in different environmental media, yet little is known about the mutual relationships of microplastics' properties across components of small inland water bodies. Here, having extracted and analyzed these particles from water, sediment, and amphibian larvae from 23 sites, we test within-site similarities regarding shape (morphological type), color, and chemical composition (polymer type). We also provide a brief characterization of the microplastics extracted from water and sediment regarding these parameters. We observed a statistically significant similarity of microplastics' shapes and colors between those extracted from water and amphibian larvae. Such a similarity, though less pronounced, was also found between amphibian larvae and sediment. However, the chemical composition (polymer type) of the microplastics from water, sediment, and amphibian larvae did not exhibit any similarities beyond what would be expected by chance. The observed congruence in the colors and shapes of microplastics between amphibian larvae and their corresponding aquatic habitats underscores the profound interconnectedness among the constituents of freshwater ecosystems.

Food on a plate: Wild geese maintain higher food intake rates on uniform winter cereals fields versus diverse grasslands.

Spring staging Greater White-fronted Geese Anser albifrons have increasingly shifted from traditional diverse grassland fields to monocultures of winter cereals, causing conflict with farmers. To account for this transition, we tested two key predictions, controlling for goose age effects and sward height. Firstly, that cereal is better quality than grass (based on crude protein content). Secondly, that geese show higher peck rate and step rate on grassland than cereal, enabling them to compensate for lower, less selective intake rates there compared to the uniform, dense, high quality arable sward where all blades are equally of high profitability. Laboratory analyses showed that winter cereal had 27 % higher crude protein content than grass. Based on data extracted from video sequences of spring foraging geese in NE Poland, first-year birds ("immatures") showed significantly higher peck rates and step rates than adults in all situations, likely reflecting their less efficient foraging abilities. Both age classes showed significantly higher peck rates on grass than winter cereal as predicted. Combining differential protein content and lamina length/dry weight relationships of grass versus cereal showed that geese obtained 17-33 % more protein from cereal lamina of the same length. At observed peck rates, this equated to a 6 % greater hourly crude protein intake rate on cereals compared to grass at lamina length 2.5 cm, increasing to 29 % difference at 12.5 cm. Hence, at longer swards, cereals become increasingly profitable for foraging geese over grass swards, despite the higher peck rates observed on grass which failed to compensate for lower lamina quality. We contend that these interactions explain the simultaneous attraction of cereal over grass swards in this study area and likely elsewhere and we discuss the management implications of these findings.

Behavioral Repertoire on a Vertical Rod-An Ethogram in Dermacentor reticulatus Ticks.

Ticks are important vectors of pathogens that endanger humans and animals. Study of their behavior under laboratory conditions is important for both predicting their behavior in natural conditions and understanding their involvement in transmission cycles of pathogens, which may lead to effective prevention of tick-borne disease transmission or establishment of effective preventive measures. The aim of our study was to describe the behavior of D. reticulatus ticks using laboratory assay. We focused on the description of individual behavioral units during their vertical movement. The assay consisted of glass beakers filled with sand and an embedded glass rod. We observed 10 different behavioral units, 4 of which have not yet been described: body posturing called "jogger", leg grooming, and body or leg jerking. The most frequent tick behavior observed was an upwards positioning of the two front legs while the body remained motionless (88.9%). Other common observations were both horizontal (63%) and vertical (58.0%) body posturing with all legs lowered, followed by questing behavior (51.9%). Ticks spent the most time questing (75.2%), crawling (54.7%), and grooming legs on the right side (23%). We did not observe any differences between males and females.

Anthropogenic transformations of river ecosystems are not always bad for the environment: Multi-taxa analyses of changes in aquatic and terrestrial environments after dredging of a small lowland river.

Rivers are one of the most commonly transformed aquatic ecosystems. Most papers present significantly negative effects of activities such as dredging or channel regulation on the ecological status of rivers. The purpose of this work was to compare the response of various groups of invertebrates (Mollusca, Hydrachnidia, Odonata, Heteroptera, Coleoptera and Trichoptera) to an intervention involving dredging in conjunction with the removal of riparian vegetation. Habitat diversity increased after the dredging, and more individuals and species were caught than before the dredging. The increase in habitat diversity after the dredging translated into an increase in the species diversity of most investigated groups. Individual groups of invertebrates showed varied responses to the dredging, depending on the role of the terrestrial phase in their life cycle: the greater the role of the terrestrial phase in the life cycle, the more the group was affected by changes in the terrestrial environment following the intervention. In consequence, the intervention had the greatest negative impact on insects, and among these, on adult Odonata. The following conclusions can be drawn: (1) Dredging can benefit a previously anthropogenically transformed river ecosystem by increasing habitat diversity; (2) Odonata are particularly useful for assessing the impact of this type of intervention on invertebrate communities. They can be considered good indicators of habitat disturbances in both aquatic and terrestrial ecosystems.

The effects of parental age difference on the offspring sex and fitness of European blackbirds.

BACKGROUND: Many studies of birds have indicated that offspring sex ratios can vary with environmental and parental traits. On the basis of long-term research, we first evaluated the possible influence of parental age difference and brood characteristics on offspring sex and fitness in multi-brooded Blackbirds Turdus merula. METHODOLOGY: The study was conducted in the city-centre Stefan Zeromski Park in Szczecin, NW Poland, where the local population of Blackbirds has been studied since 1996. Data on the offspring sex and fitness were collected in five years, 2005-2007 and 2016-2017. During the breeding season we inspected the study area to locate the pairs' territories and to track their nests and clutches. RESULTS: We found that the overall sex ratio did not differ statistically from 50:50, but that younger females bonded with older mates did tend to produce more sons, probably because of the greater fitness of male descendants. Accordingly, the sons' breeding success increased with the father's age, but this relationship was close to non-linear, which may indicate that the transgenerational effect of paternal senescence could negatively affect progeny fitness despite the high-quality of older fathers. Older females mated with younger males produced more daughters, which could have been due to the lesser attractiveness of the males and the mothers' poorer condition caused by accelerated senescence. We found that neither offspring hatching sequence nor hatching date or clutch sequence were significant for sex determination. CONCLUSIONS: We consider that in our Blackbird population, parental age could make a more significant contribution to shaping offspring sex and reproductive success.

Digit ratio in the common toad Bufo bufo: the effects of reduced fingers and of age dependency.

INTRODUCTION: Despite the growing number of studies describing digit ratio patterns in tetrapods, knowledge concerning certain basic issues is still scarce. In lower vertebrates such as tailless amphibians (Anura), the numbering of individual fingers on the forelimbs and their homology with the fingers of other vertebrates pose an unsolved problem. Based on reviewed data on anuran limb development, we argue that the correct finger numbering scheme should be based on the assumption that the first finger, not the fifth finger, was reduced on the forelimbs. We analyzed the digit ratio in the common toad (Bufo bufo, Bufonidae), a species characterized by well-developed sexual dimorphism whereby females are larger than males, using both numbering schemes present in the literature. RESULTS: We found that the digit ratio on hindlimbs differed significantly between the sexes only in the cases of left 2D:3D, with lower digit ratios in females, and of left 3D:4D, with lower digit ratios in males. We found that sex was the only significant variable for forelimbs, differentiating 2D:3D on the left forelimb, with lower digit ratios in females; 2D:4D on the right forelimb, with lower digit ratios in males; and 3D:4D on both forelimbs, with lower digit ratios in males. These results relate to variant II reflecting the hypothesis that the first digit was reduced during phylogenesis. There was no relationship between the body size (SVL) of individuals and any digit ratio, excluding 2D:4D on the right forelimbs in models with age variables. Additionally, for a subset of data where individual age was known, the models indicated that age was linked to significant differences in 2D:4D and 3D:4D on the left hindlimbs, while age, SVL, and sex influenced 2D:4D on the right forelimbs. CONCLUSION: We emphasize the importance of the problem of the correct numbering of forelimb digits in Anura and, under the assumption that it was the fifth digit that was reduced, argue that earlier results on digit ratio in this group should be interpreted with caution. The detected relationship between digit ratio and age in amphibians expands our knowledge, indicating that the age of individuals should be included in future digit ratio studies. This relationship may also apply to studies using digit ratio as a noninvasive indicator of endocrine disruption in amphibians.

The Relationship between Hunting Methods and the Sex, Age and Body Mass of Wild Boar Sus scrofa.

Increases in the wild boar Sus scrofa population create many conflicts that must be managed, especially because hunting represents a major cause of mortality in this game species. However, hunting effort is not distributed randomly and is influenced by many factors, including hunting methods. This can be especially important in understanding the nature of hunting pressure for both theoretical (ecological and evolutionary) and applied reasons (for management purposes, especially during infectious diseases, for example, African swine fever, outbreaks). We analyzed hunting data from the survey area in Western Poland from the years 1965-2016. In this period a total of 2335 wild boar were culled using two hunting methods: by individual hunters (43.8%) and by teams of hunters (52.0%). During the study period, the number of wild boars increased significantly but in a non-linear manner. More adult males and yearlings of both sexes were shot during individual hunts; more adult females were culled during team hunting. Moreover, the body mass of culled wild boars was positively influenced by the distance to a forest and during the team hunts heavier females and males were shot. To effectively control populations of wild boars, programs to reduce the number of individuals should be better planned and ensure the maintenance of proper age- and sex structure in the wild boar population.

A negative covariation between toxoplasmosis and CoVID-19 with alternative interpretations.

Coronaviruses may exert severely negative effects on the mortality and morbidity of birds and mammals including humans and domestic animals. Most recently CoVID-19 has killed about half million people (27th of June, 2020). Susceptibility to this disease appears to differ markedly across different societies but the factors underlying this variability are not known. Given that prevalence of toxoplasmosis in human societies may serve as a proxy for hygiene, and it also exerts both direct and immune-mediated antiviral effects, we hypothesize a negative covariation between toxoplasmosis and measures of the CoVID-19 pandemic across countries. We obtained aged-adjusted toxoplasmosis prevalence of pregnant women from the literature. Since the differences in the CoVID-19 morbidity and mortality may depend on the different timing of the epidemics in each country, we applied the date of first documented CoVID-19 in each country as a proxy of susceptibility, with a statistical control for population size effects. Using these two indices, we show a highly significant negative co-variation between the two pandemics across 86 countries. Then, considering that the wealth of nations often co-varies with the prevalence of diseases, we introduced GDP per capita into our model. The prevalence of toxoplasmosis co-varies negatively, while the date of first CoVID-19 co-varies positively with GDP per capita across countries. Further, to control for the strong spatial autocorrelation among countries, we carried out a Spatial Structure Analyses of the relationships between the date of first CoVID-19, prevalence of toxoplasmosis, and GDP per capita. Results of this analysis did not confirm a direct causal relationship between toxoplasmosis and susceptibility to the CoVID-19 pandemics. As far as an analysis of observational data let us to suggest, it appears that the interaction between CoVID-19 and toxoplasmosis is mediated by GDP per capita and spatial effects. This prompts the question whether the formerly known covariations of CoVID-19 and BCG vaccination or air pollution might have also emerged as spurious indirect effects.

Infected Ixodes ricinus ticks are attracted by electromagnetic radiation of 900 MHz.

The electromagnetic field (EMF) is known to influence functions of the nervous, cardiovascular and reproductive systems of many animals, including ticks. The aim of this study was to test the behavior of ticks in the presence of radio-frequency EMF. For testing, 160 adult male and 140 adult female unfed Ixodes ricinus ticks were used. Individuals were exposed to 900 MHz EMF in the Radiation-Shielded Tube (RST). Ticks were attracted to the irradiated area. This effect was significantly stronger for ticks infected with Rickettsia spp., suggesting that pathogens can alter the ticks' response to environmental stimuli. These results lead to the question of whether man-made EMF may have an impact on I. ricinus activity and, as such, be a contributing factor to the ongoing changes in the distribution of the tick and its pathogens currently observed in Europe and elsewhere.

Exposure to Pb impairs breeding success and is associated with longer lifespan in urban European blackbirds.

Although several factors have been highlighted to explain the influence of urbanization on bird fitness and survival, the role of persistent toxicants such as lead (Pb), which is typically present in urban areas worldwide, has seldom been studied despite the ecological importance of such a widespread stressor. Studying free-living European blackbirds (Turdus merula) in city parks, we tested the hypothesis that low-dose chronic exposure to Pb could shape the life-history traits of urban birds. The feather concentrations of Pb and cadmium were typical of urban areas and low-to-moderate contamination of sites. Although the lifetime breeding success of females decreased with increasing exposure to Pb, the lifespan and survival probabilities of blackbirds increased with Pb contamination regardless of gender. Breeding effort-dependent patterns in the relationship between lifespan and Pb levels were highlighted. No significant relationships were detected between cadmium and life-history traits. The results suggest a possible trade-off between self-maintenance and reproduction, with the most affected birds redirecting allocations towards their own survival, which is consistent with the "stress hormone hypothesis". These findings suggest that Pb pollution in urban environments may shape avian ecological features and be one of the drivers of wildlife responses to urbanization and that some urban areas may function as ecological traps driven by pollutants.

Waterbird counts on large water bodies: comparing ground and aerial methods during different ice conditions.

The aerial and ground methods of counting birds in a coastal area during different ice conditions were compared. Ice coverage of water was an important factor affecting the results of the two methods. When the water was ice-free, more birds were counted from the ground, whereas during ice conditions, higher numbers were obtained from the air. The first group of waterbirds with the smallest difference between the two methods (average 6%) contained seven species: Mute Swan Cygnus olor, Whooper Swan Cygnus cygnus, Greater Scaup Aythya marila, Tufted Duck Aythya fuligula, Common Goldeneye Bucephala clangula, Smew Mergellus albellus and Goosander Mergus merganser; these were treated as the core group. The second group with a moderate difference (average 20%) included another six species: Mallard Anas platyrhynchos, Eurasian Wigeon Mareca penelope, Common Pochard Aythya ferina, Great Crested Grebe Podiceps cristatus and Eurasian Coot Fulica atra. The third group with a large difference (average 85%) included five species, all of the Anatini tribe: Gadwall Mareca strepera, Northern Pintail Anas acuta, Northern Shoveler Spatula clypeata, Eurasian Teal Anas crecca and Garganey Spatula querquedula. During ice conditions, smaller numbers of most species were counted from the ground. The exception here was Mallard, more of which were counted from the ground, but the difference between two methods was relatively small in this species (7.5%). Under ice-free conditions, both methods can be used interchangeably for the most numerous birds occupying open water (core group) without any significant impact on the results. When water areas are frozen over, air counts are preferable as the results are more reliable. The cost analysis shows that a survey carried out by volunteer observers (reimbursement of travel expenses only) from the land is 58% cheaper, but if the observers are paid, then an aerial survey is 40% more economical.

Electromagnetic radiation and behavioural response of ticks: an experimental test.

Factors associated with the increased usage of electronic devices, wireless technologies and mobile phones nowadays are present in increasing amounts in our environment. All living organisms are constantly affected by electromagnetic radiation which causes serious environmental pollution. The distribution and density of ticks in natural habitats is influenced by a complex of abiotic and biotic factors. Exposure to radio-frequency electromagnetic field (RF-EMF) constitutes a potential cause altering the presence and distribution of ticks in the environment. Our main objective was to determine the affinity of Dermacentor reticulatus ticks towards RF-EMF exposure. Originally designed and constructed radiation-shielded tube (RST) test was used to test the affinity of ticks under controlled laboratory conditions. All test were performed in an electromagnetic compatibility laboratory in an anechoic chamber. Ticks were irradiated using a Double-Ridged Waveguide Horn Antenna to RF-EMF at 900 and 5000 MHz, 0 MHz was used as control. The RF-EMF exposure to 900 MHz induced a higher concentration of ticks on irradiated arm of RST as opposed to the RF-EMF at 5000 MHz, which caused an escape of ticks to the shielded arm. This study represents the first experimental evidence of RF-EMF preference in D. reticulatus. The projection of obtained results to the natural environment could help assess the risk of tick borne diseases and could be a tool of preventive medicine.

Prevalence of smoking and BMI differences between smokers and non-smokers among children and adolescents aged 7-18 years in south-east Poland.

ABSTRACT: Objectives: The aim of the study was to determine the prevalence of smoking among children and adolescents aged 7-18 years, and also to determine the relationship between this addiction and the Body Mass Index (BMI). Methods: Basic anthropometric measurements were performed, and information concerning cigarette smoking and basic SES was gathered using the questionnaire method. Results: More than 5% of boys admit to smoking at the age of 10-11 years, and as many as 22% 18-year-olds admit to doing so. With regard to girls, the situation is slightly better because it is only among 14-year-olds that the percentage of smokers exceeds 5%. Smoking may affect average BMIs. Smoking had a negative impact on the magnitude of physical development indices among children between 8 and 12 years old. Conclusions: The percentage of smokers increases with age. Boys smoke more often than girls. Tobacco smoking in middle childhood (8-12 years) is associated with lower BMIs.

Experimentally evoked same-sex sexual behaviour in pigeons: better to be in a female-female pair than alone.

Same-sex sexual behaviour has been noted among social animals. However, because of the large number of observations necessary, data from controlled experiments are lacking. In this study, we performed experiments to evaluate the effects of male and female removal in colonies of the feral pigeon (Columba livia f. urbana). After the experimental removal of males, five long-lasting female-female pairs occurred. We found that those pairs could successfully raise offspring in a manner comparable to female-male pairs. Same-sex sexual behaviour and pairing in females is thus a better alternative to postponed breeding or breeding alone without the help of a partner. In contrast, in the case of female-removal experiments, same-sex pairing behaviour occurred in males as a temporary phenomenon with characteristic mutual aggression. Additionally, under a male-biased sex ratio, we observed father-son and father-daughter copulations. To the best of our knowledge, these results are the first obtained under controlled experimental conditions which demonstrate that the sex ratio of a population can shift the social structure and cause cooperative same-sex breeding behaviour to arise in a monogamous species.

Ducks change wintering patterns due to changing climate in the important wintering waters of the Odra River Estuary.

Some species of birds react to climate change by reducing the distance they travel during migration. The Odra River Estuary in the Baltic Sea is important for wintering waterfowl and is where we investigated how waterbirds respond to freezing surface waters. The most abundant birds here comprise two ecological groups: bottom-feeders and piscivores. Numbers of all bottom-feeders, but not piscivores, were negatively correlated with the presence of ice. With ongoing global warming, this area is increasing in importance for bottom-feeders and decreasing for piscivores. The maximum range of ice cover in the Baltic Sea has a weak and negative effect on both groups of birds. Five of the seven target species are bottom-feeders (Greater Scaup Aythya marila, Tufted Duck A. fuligula, Common Pochard A. ferina, Common Goldeneye Bucephala clangula and Eurasian Coot Fulica atra), and two are piscivores (Smew Mergellus albellus and Goosander Mergus merganser). Local changes at the level of particular species vary for different reasons. A local decline of the Common Pochard may simply be a consequence of its global decline. Climate change is responsible for some of the local changes in the study area, disproportionately favoring some duck species while being detrimental to others.

Patterns in the distribution and directional asymmetry of fleas living on the northern white-breasted hedgehog Erinaceus roumanicus.

Fleas infecting northern white-breasted hedgehogs, Erinaceus roumanicus (Barrett-Hamilton), collected from 2009-2011 in Budapest (Hungary) were studied. A total of 305 white-breasted hedgehogs were captured and 1,251 fleas were collected. The flea community comprised two species, the hedgehog flea Archaeopsylla erinacei (Bouche, 1835) and the dog flea Ctenocephalides canis (Curtis, 1826), although the latter was only found on three hedgehogs. Fleas were found on half of the host specimens (51%; n = 156) where their distribution was strongly aggregated. The sex ratio of A. erinacei was biased towards females and was correlated with host size. Interestingly, the sex ratio of fleas became more equal on heavier hosts. It had been expected that, under high competition, the sex ratio would be female biased because it is known that female ectoparasites dominate on poorer hosts. The body size of a random sample of 200 fleas (100 female and 100 male) was measured under a microscope. The analyses showed directional asymmetry in two features - the distance between the top of the head and the eye, and head length. In this two body traits the left side was significantly greater than right side in both sexes of A. erinacei. Our data shed light on the complex nature of the flea population infecting northern white-breasted hedgehogs in an urban area.

Habitat preferences of two sparrow species are modified by abundances of other birds in an urban environment.

Every species has certain habitat requirements, which may be altered by interactions with other co-occurring species. These interactions are mostly ignored in predictive models trying to identify key habitat variables correlated with species population abundance/occurrence. We investigated how the structure of the urban landscape, food resources, potential competitors, predators, and interaction between these factors influence the abundance of house sparrow Passer domesticus and the tree sparrow P. montanus in sixty 25 ha plots distributed randomly across residential areas of the city of Poznan (Poland). The abundance of the house sparrow was positively correlated with the abundance of pigeons but negatively correlated with human-related food resources. There were significant interaction terms between abundances of other urban species and habitat variables in statistical models. For example, the abundance of house sparrow was negatively correlated with the abundance of corvids and tree sparrows but only when food resources were low. The abundance of tree sparrows positively correlated with density of streets and the distance from the city center. The abundance of this species positively correlated with the abundance of corvids when food resources were low but negatively correlated at low covers of green area. Our study indicates that associations between food resources, habitat covers, and the relative abundance of two sparrow species are altered by the abundance of other urban species. Competition, niche separation and social facilitation may be responsible for these interactive effects. Thus, biotic interactions should be included not only as an additive effect but also as an interaction term between abundance and habitat variables in statistical models predicting species abundance and occurrence.