Microplastics (MPs) are one of the major threats to aquatic ecosystems. Surprisingly, our knowledge of its occurrence and its impact on the organisms that dwell in small water bodies is still scarce. ...The aim of this study was to investigate the occurrence and chemical composition of MPs in tadpoles of pond-breeding amphibians. In total, 201 tadpoles belonging to 5 species were collected from 8 ponds located in southwestern Poland. MPs were found in all examined sites and in all studied species. Among those tested, 53 (26%) tadpoles ingested a total of 71 MPs. IR-ATR analysis revealed that particles were of anthropogenic origin and included nylon, polyurethane, polyisoprene and 1,2 polybutadiene.
The widespread occurrence of litter is a severe threat to global ecosystems. We have analyzed online media, to assess the diversity of animals that are prone to getting trapped in discarded ...containers and check which kind of containers is the most common trap for animals. A total of 503 records from around the world (51 countries, 6 continents) have been found. These include invertebrates (17 taxa, ca.1050 dead individuals), and vertebrates (98 taxa, 496 individuals including 44 carcasses). The latter group was most frequently represented by mammals (78.5% of all cases), then reptiles (15.3%), birds (1.2%), fish (1.0%) and amphibians (0.4%). Nearly 12.5% of the determined vertebrates are classified as vulnerable, endangered or critically endangered, according to the IUCN. Although most trapped individuals were smaller animals, bigger ones such as monitor lizards (Varanus spp.) or large carnivores were also recorded. In most cases, animals were trapped in glass or plastic jars (32.4%), drink cans (16.5%), and steel cans (16.3%). Our results demonstrate that discarded containers can be a threat to all major groups of animals. In order to address this phenomenon, it is necessary to decrease a global production of debris, implement container deposit legislation and organize repeatable cleanup actions.
Increased urbanisation is leading to littering of the environment. However, some animals may adapt to live in such altered habitats. The aim of this study was to assess whether discarded containers ...can serve as a suitable microhabitat for spiders. The study was conducted in 10 woodland areas in the city of Wrocław, Poland. In September 2018, a total of 939 containers were collected, of which 33.5% contained evidence of spiders having resided therein: webs, dead or living spiders, exuviae or cocoons. A total of 22 species and several other taxa that could not be recognised so accurately were detected. The most common of these belonged to Linyphiidae and Theridiidae. Juveniles (N = 103) dominated over adults (N = 58), and females (N = 34) were more numerous than males (N = 24). In 15 containers, interspecies pairs were found. Among ecological guilds, sheet web spiders dominated (60%) followed by space web spiders (24%), ground hunters (9%), ambush hunters (3%), specialists (3%), and other hunters (2%). Spiders were significantly more often found in colourless (38.3%) and green (35.5%) than in brown bottles (25.2%). They were also more numerous in glass bottles for sweet drinks (50.0%) than in beer bottles (28.0%), and slightly more frequent than in glass vodka bottles (33.3%). Our study showed that discarded containers are fully exploitable microhabitats for spiders and are used by these animals for at least three different purposes: hunting, hiding and breeding, however the effect on their fitness remains unknown.
Cryptic phylogeographic diversifications provide unique models to examine the role of phylogenetic divergence on the evolution of reproductive isolation, without extrinsic factors such as ecological ...and behavioural differentiation. Yet, to date very few comparative studies have been attempted within such radiations. Here, we characterize a new speciation continuum in a group of widespread Eurasian amphibians, the Pelobates spadefoot toads, by conducting multilocus (restriction site associated DNA sequencing and mitochondrial DNA) phylogenetic, phylogeographic and hybrid zone analyses. Within the P. syriacus complex, we discovered species‐level cryptic divergences (>5 million years ago My) between populations distributed in the Near‐East (hereafter P. syriacus sensu stricto s.s.) and southeastern Europe (hereafter P. balcanicus), each featuring deep intraspecific lineages. Altogether, we could scale hybridizability to divergence time along six different stages, spanning from sympatry without gene flow (P. fuscus and P. balcanicus, >10 My), parapatry with highly restricted hybridization (P. balcanicus and P. syriacus s.s., >5 My), narrow hybrid zones (~15 km) consistent with partial reproductive isolation (P. fuscus and P. vespertinus, ~3 My), to extensive admixture between Pleistocene and refugial lineages (≤2 My). This full spectrum empirically supports a gradual build up of reproductive barriers through time, reversible up until a threshold that we estimate at ~3 My. Hence, cryptic phylogeographic lineages may fade away or become reproductively isolated species simply depending on the time they persist in allopatry, and without definite ecomorphological divergence.
An intriguing outcome of hybridisation is the emergence of clonally and hemiclonally reproducing hybrids, that can sustain, reproduce, and lead to the emergence of polyploid forms. However, the ...maintenance of diploid and polyploid hybrid complexes in natural populations remains unresolved. We selected water frogs from the Pelophylax esculentus complex to study how diploid and triploid hybrids, which reproduce hemiclonally via hybridogenesis, are maintained in natural populations. During gametogenesis in diploid hybrids, one of the parental genomes is eliminated, and the remaining genome is endoreplicated. In triploid hybrids, the single-copy genome is typically eliminated, while genome endoreplication does not occur. To investigate how diploid and triploid hybrid frogs reproduce in populations without parental species, we crossed these hybrid animals from two separate pure hybrid populations located in Poland. Using cytogenetic analysis of tadpoles that emerged from the crosses, we established which gametes were produced by parental hybrids. The majority of hybrid females and hybrid males produced one type of gamete with the P. ridibundus genome. However, in both studied populations, approximately half of the diploid and triploid hybrids simultaneously produced gametes with different genome compositions and ploidy levels, specifically, the P. ridibundus and P. lessonae genomes, as well as diploid gametes with genomes of both parental species. Triploid hybrid males and females mostly produced haploid gametes with the P. lessonae genome; however, gametes with the P. ridibundus genome have also been observed. These results suggest that not all hybrids follow the classical hybridogenetic reproduction program and reveal a significant level of alterations in the gametogenesis pathways. In addition, we found a variable survival rate of particular progeny genotypes when we crossed hybrid females with different males suggesting the important role of postzygotic barriers on the maintenance of pure hybrid systems. We suggest that the observed variability in produced gametes and the different survival rate of the progeny with certain genotypes is crucial for the existence of pure hybrid systems.
The distribution of the chytrid fungus Batrachochytrium salamandrivorans continues to expand in Europe. During 2014-2018, we collected 1,135 samples from salamanders and newts in 6 countries in ...Europe. We identified 5 cases of B. salamandrivorans in a wild population in Spain but none in central Europe or the Balkan Peninsula.
DNA elimination is a radical form of gene silencing and occurs both in somatic and germ cells. The programmed DNA elimination occurs during gametogenesis in interspecies hybrids that reproduce by ...hybridogenesis (stick insects, fishes, and amphibians) and concerns removal of whole genomes of one of the parental species and production of clonal gametes propagating the genome of the other species. The cellular mechanisms differ considerably in hybridogenetic insects and fishes but remains unknown in edible frogs Pelophylax esculentus, natural hybrids between Pelophylax lessonae and Pelophylax ridibundus. Here we report DNA elimination mechanism in early developing gonads of diploid and triploid hybrid frogs, studied by TEM, immunofluorescence, and cytochemistry. In gonocytes of both sexes (primary oogonia and prespermatogonia), micronuclei emerge as detached nuclear buds formed during interphase. We found depletion of nuclear pore complexes in micronuclear membrane and chromatin inactivation via heterochromatinization followed by degradation of micronuclei by autophagy. Micronuclei formation does not lead to apoptotic cell death showing that genome elimination is a physiological process. Chromatin elimination via micronuclei in P. esculentus is unique among hybridogenetic animals and contributes to broadening the knowledge about reproductive modes in animals.
The presence of anthropogenic waste in the environment is one of the most pervasive pollution problems affecting wildlife around the world. Among different types of rubbish, beverage containers ...represent an ecological trap for invertebrates. However, it also may serve as a nest site. In the present study, we aim to assess if ants can exploit discarded containers as nesting sites, the intensity of mortality of ant workers foraging discarded containers, and ant preferences toward particular features of containers. The study was conducted in September 2018 in 10 woodland areas in the city of Wrocław, Poland. In total, 4.4% of 939 collected containers were used as nest sites by four ant species. Additionally, we found 698 dead workers, representatives of at least 11 species, in 10.3% of investigated containers. Most frequently, ants inhabited brown plastic and glass bottles, and an increase in neck diameter of containers decreased the possibility of nest occurrence. Dead workers were marginally significantly more often found in colourless glass bottles when compared to brown ones and were more frequent in sweet drink and vodka bottles than in beer bottles. Additionally, larger capacity increased the frequency of occurrence of dead ants. Although ants use anthropogenic waste as nest sites, it predominantly appears as a threat for foraging ant workers, most probably attracted by the smell of fermenting beverages or decomposing carcasses of previously trapped animals. Thus, to protect species inhabiting human-disturbed habitats, we suggest developing tools helping to prevent the accumulation of waste in urban woodlands.
•4.4% of discarded containers collected in urban woodlands were used as nesting sites by four ant species.•In 10.3% containers, 698 dead workers, of at least 11 species, were found.•Increase in neck diameter of containers decreased the possibility of nest occurrence.•Larger capacity of container increased the frequency of occurrence of dead ants.•Protection of invertebrates’ diversity in urban ecosystems requires developing tools limiting the accumulation of waste.
Hybridogenesis is a hemiclonal reproductive strategy in diploid and triploid hybrids. Our study model is a frog
P. esculentus
(diploid RL and triploids RLL and RRL), a natural hybrid between
P. ...lessonae
(LL) and
P. ridibundus
(RR). Hybridogenesis relies on elimination of one genome (L or R) from gonocytes (G) in tadpole gonads during prespermatogenesis, but not from spermatogonial stem cells (SSCs) in adults. Here we provide the first comprehensive study of testis morphology combined with chromosome composition in the full spectrum of spermatogenic cells. Using genomic
in situ
hybridization (GISH) and FISH we determined genomes in metaphase plates and interphase nuclei in Gs and SSCs. We traced genomic composition of SSCs, spermatocytes and spermatozoa in individual adult males that were crossed with females of the parental species and gave progeny. Degenerating gonocytes (24%–39%) and SSCs (18%–20%) led to partial sterility of juvenile and adult gonads. We conclude that elimination and endoreplication not properly completed during prespermatogenesis may be halted when gonocytes become dormant in juveniles. After resumption of mitotic divisions by SSCs in adults, these 20% of cells with successful genome elimination and endoreplication continue spermatogenesis, while in about 80% spermatogenesis is deficient. Majority of abnormal cells are eliminated by cell death, however some of them give rise to aneuploid spermatocytes and spermatozoa which shows that hybridogenesis is a wasteful process.
We present four cases of rare developmental anomalies in the smooth snake
Coronella austriaca
Laurenti, 1768 from western Poland. These include brachycephaly, lordosis, a supernumerary row of ...‘ventral’ scales, and the third reported case of dicephalism in snakes from Poland. All the cases are supported by X-ray radiography. One of the possible explanations for these anomalies is a low genetic variation in populations from western Poland.
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