Glis Glis Research Articles

Direct evidence for nest predation by the edible dormouse (Glis glis, Rodentia) in open-cup nesting songbirds

Direct evidence for nest predation by the edible dormouse (Glis glis, Rodentia) in open-cup nesting songbirds

No negative effects of intra-abdominal bio-logger implantation under general anaesthesia on spatial cognition learning in a hibernator the edible dormouse.

The effect of hibernation on cognitive capacities of individuals is not fully understood, as studies provide conflicting results. Most studies focus on behavioural observations without taking the physiological state of individuals to account. To mechanistically understand the effect of hibernation on the brain, physiological parameters need to be included. The implantation of bio-loggers can provide insights on i.e. body temperature without further manipulation of the animals. Surgeries and anaesthesia, however, can harm animals' health and cause cognitive dysfunction, potentially biasing data collected through bio-loggers. We investigated the effects of bio-logger implantation surgery on cognitive performance and learning, controlling for animal and study design characteristics. First, juvenile dormice successfully learned to solve a spatial cognition task using a vertical maze. Distance, transitions, velocity, and duration were measured as indicators for performance. After training, bio-loggers were implanted intra-abdominally under general anaesthesia. Animals were re-tested in the maze two weeks after. We found no effect of bio-logger implantation and surgery on performance. This study is the first to show spatial cognition learning in edible dormice and provides a full description of the peri-anaesthetic management and a protocol for bio-logger implantation surgery in dormice. Importantly, measures were taken to mitigate common anaesthetic complications that could lead to post-operative cognitive dysfunction and influence animal behaviour. By pairing physiological measurements through bio-logger implantation with behaviour and cognition measurements, future research will significantly advance the understanding on mechanisms of learning and behaviour.

Direct and indirect effects of climate and seed dynamics on the breeding performance of a seed predator at the distribution edge.

Marginal populations usually have low densities and are considered to be particularly vulnerable to environmental stochasticity. Using data collected in nest boxes, we analyzed the breeding performance of the edible dormouse (Glis glis), an obligate hibernating rodent and a seed predator in deciduous forests, in two populations at the distribution range's edge. Despite being only 20 km apart from each other, Montseny is a large patch of mixed deciduous forests (oaks and beech), whereas Montnegre would be the harshest habitat, that is, a small, isolated patch with only oaks. First, we studied the differences in climate and tree cover change in the two populations. Second, we analyzed the direct and indirect roles of local climate conditions and seed availability on breeding performance over 10 years in each population. Finally, we explored the influence of tree cover change on the occupancy dynamics in the two populations. Our results showed contrasting responses between populations: in Montseny, asynchronous seed production between oaks and beech precluded skip breeding, and breeding performance increased with seed availability. Furthermore, dormice in Montseny may use pollen production to anticipate the amount of beech nut resources and adjust their breeding effort. Boxes showed higher occupancy and colonization and fewer extinctions in Montseny than in Montnegre, where seed availability did not drive breeding performance. Results from Montnegre suggest that skip breeding was an adaptive response to a more pulsed, harsher environment. Here, females produced a similar number of pups than at Montseny. Long-term studies dealing with population responses in marginal habitats can lead to a deeper understanding of the capacities of organisms to adapt to harsh environments. Although local adaptation is frequently documented across various taxa, studies at the distribution edge may shed light on our still limited comprehension of the underlying mechanisms responsible for its occurrence.

Diversity and plasticity of vocalisations in an elusive and arboreal small mammal: the edible dormouse (Glis glis)

ABSTRACT The acoustics of small mammals, particularly dormice species, are generally understudied. During this study, we explored the vocalisations and acoustic behaviour of the edible dormouse (Glis glis) in various environments in Catalonia using ultrasound recorders. Up to five different types of calls were identified in various environmental conditions (captivity and free-ranging animals) and developmental stages, from pups to adults. Additionally, one new call type was described. Significant differences were observed between captive and wild dormice (e.g. length of the calls and position of the peak harmonic), enhancing the plasticity of their vocalisations. In addition, ultrasonic sound production was discovered in pups, suggesting ontogenetic changes in the vocal repertoire. The lack of differences in vocalisations between sexes reported in captivity highlight the importance of traditional monitoring methods (i.e. nest boxes) for population monitoring in the case of the edible dormouse. The potential of the acoustic method as a non-invasive tool for studying ecological behaviours and interactions, or early detection of the species in the natural environment is emphasised. This study provides an open call reference library, laying the groundwork for a better understanding of edible dormouse acoustics, and focuses on the importance of future research to explore the acoustic social behaviour of the species.

Anthropogenic dispersal explains the phylogeography of insular edible dormouse Glis glis in the Mediterranean basin

The history of human colonisation in the Mediterranean has long been recognised as a crucial factor influencing biodiversity patterns in southern Europe. Nonetheless, our understanding of how anthropogenic and natural dispersal events interacted in shaping wildlife distributions, particularly in small mammals, remains limited. The edible dormouse Glis glis, a widespread European species, whose distribution includes several islands in the Mediterranean, present an opportunity to investigate these interactions. In this work, we used the edible dormouse to test hypotheses regarding the interplay between natural and anthropogenic dispersal in shaping species’ distributions in Mediterranean archipelagos. We compared genetic sequences from samples collected on Mediterranean islands (Elba Island, Corsica, Sardinia, Sicily and Salina Island) and the mainland. Twenty-one samples were analysed by amplifying and sequencing a fragment of the cytochrome oxidase subunit I gene. Results indicated that samples from Sardinia and Elba Island belong to the same clade of mainland Italy, specifically to the subspecies G. g. italicus. This finding does not support the existence of an endemic Sardinian subspecies and suggests recent introduction events. In contrast, Salina Island only included individuals belonging to the Sicilian subspecies, whereas Sicily hosts a mixed population of G. g. italicus and G. g. insularis. The Corsican population likely originated from a different stock than Sardinia, possibly originating from Northern Italy or southern France. Overall, our findings underscore the significant role of anthropogenic dispersal in shaping the current distribution of the edible dormouse on islands.

The animal remains from Calle Almendralejo nr. 41 (Mérida, Spain): A contribution to our understanding of animal husbandry in the capital of Roman Lusitania

The study of zooarchaeological collections from Mérida is still rare, lacking above all information on the Romans diet and animal management. Here we present the description of the fauna found in a dump next to the northern part of the Roman wall, which also includes some contexts of ritual nature, dated to the 1st century AD until the beginning of 5th century AD. The osteological remains of animals have shown that most of them come from food waste and worked bones. We can see that there is a temporal evolution in the use of that space and in the species used, with smaller animals being preferred in the first phase and cattle being more abundant in the 4th century. Some improvement indicators were also identified, as would be expected for a provincial capital, such as Emerita Augusta. Also, ritual burials of numerous dogs as well as a skeleton of the oldest specimen in Iberia of Egyptian mongoose, camel and an edible dormouse, constitute interesting discoveries in this assemblage, demonstrating that this is an exceptional sample.

Nest box occupancy dynamics by hazel dormice (Muscardinus avellanarius) in central-western Romania

The hazel dormouse, Muscardinus avellanarius is a vulnerable and protected species that is challenging to study due to its specific way of life. Limited data on its distribution and population parameters are available for Romania. We collected data regarding species’ biology and ecology in the hilly areas of central-western Romania, within deciduous forests dominated by oak or beech species. We regularly monitored 80 wooden nestboxes, which served as shelter and breeding sites for the species, to assess the seasonal and sex-related variations in nest box usage. The highest occupancy levels were observed during the autumn, with a smaller peak in the spring. Males occupied more nest boxes than females, although the difference was not statistically significant. They also travelled greater distances. Most nest boxes were occupied by a single individual at a time. Recapture rates did not differ significantly between males and females, and most individuals were recaptured only once. Hazel dormice showed a high level of site fidelity, often returning to the same nestbox or one nearby. Interestingly, 14% of the females bred twice a year, which is a lower percentage compared to findings from other studies. Nest box occupancy rates in this region were also lower than those reported in other areas. However, it is important to note that these variations may be attributed to differences in methodology. The occupancy rate declined with the increased presence of the larger species, the fat dormouse Glis glis, which outcompeted the hazel dormouse.

Two novel Bartonella (sub)species isolated from edible dormice (Glis glis): hints of cultivation stress-induced genomic changes.

Bartonelloses are neglected emerging infectious diseases caused by facultatively intracellular bacteria transmitted between vertebrate hosts by various arthropod vectors. The highest diversity of Bartonella species has been identified in rodents. Within this study we focused on the edible dormouse (Glis glis), a rodent with unique life-history traits that often enters households and whose possible role in the epidemiology of Bartonella infections had been previously unknown. We identified and cultivated two distinct Bartonella sub(species) significantly diverging from previously described species, which were characterized using growth characteristics, biochemical tests, and various molecular techniques including also proteomics. Two novel (sub)species were described: Bartonella grahamii subsp. shimonis subsp. nov. and Bartonella gliris sp. nov. We sequenced two individual strains per each described (sub)species. During exploratory genomic analyses comparing two genotypes ultimately belonging to the same species, both factually and most importantly even spatiotemporally, we noticed unexpectedly significant structural variation between them. We found that most of the detected structural variants could be explained either by prophage excision or integration. Based on a detailed study of one such event, we argue that prophage deletion represents the most probable explanation of the observed phenomena. Moreover, in one strain of Bartonella grahamii subsp. shimonis subsp. nov. we identified a deletion related to Bartonella Adhesin A, a major pathogenicity factor that modulates bacteria-host interactions. Altogether, our results suggest that even a limited number of passages induced sufficient selective pressure to promote significant changes at the level of the genome.

The influence of landscape features on the population connectivity and genetic structure of the Edible Dormouse Glis glis in Poland

Abstract In this study, we analyze and compare the genetic structure of edible dormice representing five populations, inhabiting forest complexes in southwestern Poland that differ in their degree of fragmentation and isolation. Total genomic DNA was isolated from hairs with bulbs of 145 individuals captured between 2018 and 2020. All dormice sampled were genotyped at 14 microsatellite loci. Population genetic analyses showed that genetic variability in the studied dormice, assessed based on observed and expected heterozygosity as well as allelic richness, was on average very low (0.39, 0.43, and 2.83, respectively). In the populations studied, genetic structure was detected indicating two or five distinct genetic clusters, the existence of which can be attributed to either historical factors or modern human activity. Genetic differentiation between dormice living in the studied localities, determined by FST, ranged from 0.07 to 0.40 (all FST coefficients were significant at P < 0.05). A significant positive correlation was detected between genetic differentiation and geographic distance (r = 0.645, P < 0.017), indicating that genetic differentiation increases with distance, but no correlation between genetic differentiation and habitat barriers (r = 0.359, P < 0.132). The results of this research are compared to those of other European populations of edible dormice, and implications for the future of this endangered species are discussed.

Let me know your name: a study of chigger mites (Acariformes: Trombiculidae) associated with the edible dormouse (Glis glis) in the Carpathian-Balkan distribution gradient.

Trombiculid mites were collected from the edible dormouse (Glis glis) within the Carpathian-Balkan distribution gradient of host species. Representatives of five genera (Leptotrombidium, Neotrombicula, Brunehaldia, Hirsutiella, Schoutedenichia) and 10 species of chiggers were discovered in the material, based on morphological and/or molecular data. Brunehaldia, new to the fauna of Greece, was recorded for the first time from the edible dormouse. Neotrombicula talmiensis was new to the fauna of Greece and Neotrombicula vulgaris was new to the fauna of North Macedonia. Successful amplification and sequencing of COI was carried out in relation to three genera and six species. The intraspecific variation of taxa hitherto distinguished based on morphological criteria was juxtaposed with molecular data, using the distance method and the phylogenetic approach. The molecular methods indicated wider than hitherto recognized, intraspecific morphological variation for Leptotrombidium europaeum and N. talmiensis. On the other hand, an inference limited to morphology proved to be insufficient for species delineation, which was confirmed by the relatively low identity (%) of examined COI sequences as well as the size of inter-/intraspecific K2P distance threshold. Our study provides support for integrative taxonomy that combines different sources of evidence and contributes to recognition of the scope of intraspecific variation. The high degree of hidden diversity revealed with the application of molecular tools, votes for a careful approach to the identification of chiggers. The confirmed cases of co-invasion, including the representatives of various genera (Leptotrombidium and Neotrombicula, Brunehaldia and Neotrombicula, Neotrombicula and Schoutedenichia, Hirsutiella and Schoutedenichia) additionally support the need to include all larvae found on a given host specimen in the identification process.

Influences of Maternal Weight and Geographic Factors on Offspring Traits of the Edible Dormouse in the NE of the Iberian Peninsula.

The main goal of this study was to analyze the reproductive patterns of edible dormouse (Glis glis) populations in the northeast of the Iberian Peninsula using an 18-year period of data obtained from nest boxes collected between 2004 and 2021. The average litter size in Catalonia (Spain) was 5.5 ± 1.60 (range: 2-9, n = 131), with litter sizes between 5 and 7 pups as the more frequent. The overall mean weight in pink, grey and open eyes pups was 4.8 g/pup, 11.7 g/pup and 23.6 g/pup, respectively. No differences in offspring weights between sexes were found in any of the three age groups. Maternal body weight was positively associated with mean pup weight, whereas no correlation between the weight of the mothers and litter size was found. The trade-off between offspring number and size was not detected at birth. Regarding litter size variation across the geographic gradient (and their climatic gradient associated) from the southernmost populations of the Iberian Peninsula located in Catalonia to the Pyrenees region in Andorra, no evidence to suggest that geographic variables affect litter size was found, discarding (1) an investment in larger litters to compensate shorter seasons related to higher altitudes or northern latitudes, and (2) variation in litter size related to weather changes (e.g., temperature and precipitation) along latitudinal and/or altitudinal gradients.

A record of a melanistic forest dormouse Dryomys nitedula in Lithuania, with a review of colour anomalies in dormice (Gliridae)

A melanistic forest dormouse Dryomys nitedula was recorded among 125 individuals marked in a small isolated local population in central Lithuania. Until now, a totally black individual of D. nitedula was captured only in western Ukraine. A review of the literature on colour anomalies in European dormouse species has shown that this phenomenon is rare in dormice. Several black hazel dormice Muscardinus avellanarius were recorded in the same locality in northern Germany in 1972 and 2015, and one such dormouse was captured in the UK. Partial albino M. avellanarius was recorded in Germany. Two melanistic garden dormice Eliomys quercinus were collected in the Czech Republic, an albino specimen in France and a flavistic specimen in Germany. In the edible dormouse Glis glis, melanistic, albino, isabelline and flavistic individuals were recorded, all from Slovenia and the Czech Republic. Among aberrant-coloured European dormice, melanistic individuals were documented most often. Tail-tip albinism is more frequent among M. avellanarius, and this trait was recorded in several countries.

Some ecological peculiarities of the Fat Dormouse (Glis glis Linnaeus, 1766) in Hyrcanian relict forests of Northern Iran

Some ecological peculiarities of the Fat Dormouse (Glis glis Linnaeus, 1766) in Hyrcanian relict forests of Northern Iran

Main functions of loud vocalization in populations of edible dormouse Glis glis

The study aimed to determine when, during summer activity, males and females of the edible dormouse most often used loud calls. On this basis, an attempt was made to determine the main purpose of the emission of these calls. It was assumed that 1) if males have the most of loud calls in July, their emissions may be related primarily to the mating behaviour (which takes place during this period), and if they have the most of loud calls in August, their emissions are most likely concerned defence of food resources, 2) in females, most of this vocalization would occur in August due to the need to defend their food resources and 3) in both sexes, more vocalization would occur in the year of good beech fruit crop (when the dormice would reproduce) than in the year of no crop (when the dormice would not reproduce). To check these assumptions, the number of loud calls and “performances” (series of loud calls) emitted by the animals from two wild populations tracked by telemetry was noted. The mean number of “performances” and loud calls in males and females was higher in August than in July (when beech fruits ripen), but significant differences were found only for “performances”. Both males and females had significantly more “performances” and loud calls in the mast/breeding year than in the non-mast/non-breeding year. It seems that males and females use loud calls mainly to defend important resources and are, therefore, most often heard during the mast year.

Изучение биологии гнездования беркута с помощью фотоловушек

Trap camera was installed in an active nest of Golden Eagles (Aquila chrysaetos) in Eastern Rhodopes, Bulgaria. The recordings encompassed 45 days in June and July and the camera took 12 900 photos, from the time when the single nestling was ca. 32 days old until its fledging. 84 food deliveries were recorded, with the prey identified in 76 of them. Land tortoises dominated the diet (65% of the items), followed by Edible Dormouse (Glis glis) (10.5%), snakes (7.9%), and European Hare (Lepus europaeus) (5.2%). The two adults were easily individually identifiable by plumage characteristics, especially on the medium coverts. We recorded unexpectedly high intensity of adding the green material to the nest and cleaning the nest from prey remains, 105 and 35 cases respectively, both done almost exclusively by the female, while the male delivered most of the food – 60 vs 21 of the cases. The female was roosting in the nest with the nestling until when it was 50 days old, after which roosted in the nest only once during a rainy night when nestling was 58 days old. The method provided opportunity for following the lifetime reproductive success of unmarked Golden Eagles.

On the retinae of Glis and Graphiurus: photoreceptor and ganglion cell populations, an absence of shortwave-sensitive cones, and some other features (Rodentia: Gliridae)

The retina of the fat dormouse Glis glis was studied histologically. Opsin immunolabeling identified an unusually dense population of rod photoreceptors (ca. 600,000–780,000/mm²) and a low-density population of L cone photoreceptors containing the longwave-sensitive (LWS) cone opsin, with a shallow maximum of ca. 3,300/mm² in temporal retina and ca. 2,000–3,000/mm² in the remaining retina. Hence the cones comprise only 0.25–0.50% of the photoreceptors. There are no S cones expressing the shortwave-sensitive (SWS1) opsin that is the second cone opsin in most mammals, conveying dichromatic colour vision. We conclude that the fat dormouse is a cone monochromat. Sequencing of the tuning-relevant exon 1 of the SWS1 opsin gene revealed that the gene would have coded for a UV-sensitive visual pigment, but that it contains mutational changes making it nonfunctional. Retinal interneurons (rod bipolar cells, horizontal cells, several amacrine cell types) have rodent-typical features. NeuN-labeled presumed retinal ganglion cells have densities between ca. 4000/mm² in temporal central retina and 850–1300/mm² in peripheral retina. The peak ganglion cell density would result in an estimated visual acuity maximum of ca. 1.8 cycles/degree or ca. 33 minutes of arc. Assessment of a further Gliridae species, the African dormouse Graphiurus sp., also revealed a high rod density, low L cone density, and an absence of SWS1 opsin.

Isolation Time and Craniometric Differences between Edible Dormouse (Glis glis L., Gliridae, Rodentia) Populations Inhabiting the Greater Caucasus and the Hyrcanian Forest in Southern Azerbaijan

Isolation Time and Craniometric Differences between Edible Dormouse (Glis glis L., Gliridae, Rodentia) Populations Inhabiting the Greater Caucasus and the Hyrcanian Forest in Southern Azerbaijan

Fatty Acid Composition of M. Biceps Femoris of Edible Dormouse (Glis glis L.).

This study aimed to investigate the fatty acid (FA) composition of edible dormouse m. biceps femoris in both sexes. More than 20 FA were identified in the muscle, with the 18:1cis-9 (oleic acid) being the most abundant in both sexes, comprising more than 50% of total FA in muscle. The most dominated FA were monounsaturated (MUFA), followed by saturated FA (SFA) and polyunsaturated FA (PUFA), reaching 54.8%, 25.43% and 19.8% of total FA, respectively. Sums of PUFA and n-3 PUFA tended (p > 0.05) to be higher in males than in females. There were no significant differences between sexes on the FA composition. Nevertheless, the 18:2n-6 tended to differ between sexes (p = 0.063). Several long-chain PUFA (LC-PUFA) were detected in dormouse muscle, with the 20:4 n-6 (arachidonic acid, AA) and the 22:6 n-3 (docosahexaenoic acid, DHA) being the most abundant in both sexes. The relatively high stearoyl-CoA desaturase (SCD) indexes and the large concentration of 18:1cis-9 in dormouse muscle tissues might point to a low mobilization of the SCD products. Furthermore, finding the unusual FA 20:3 ∆5,∆11,∆14, suggests feeding on leaf and wood lipids of Coniferophytes. We demonstrated sexual size monomorphism in edible dormouse. The literature regarding the composition of dormouse meat is scarce and no studies reported the FA composition of muscle, thus, this work can contribute to increasing the knowledge on edible dormouse physiology and nutritional traits.

Postembryonic Development of The Edible Dormouse (Glis Glis Linnaeus, 1766)

The period of postnatal development in the edible dormouse occurs before hibernation, causing a restricted period of growth. Four stages can be identified according to the morphological development and behavior in the nesting period. Dormice are born completely naked, unable to move independently. During the second stage (11–21 days), juveniles acquire a variety of movements. The third stage (22–30 days) begins with opening the eyes and is associated with the activity outside the nest. During the fourth stage (31–44 days) juveniles gradually become independent of their mother. Bright peculiarity of the species postembryonic development is three simultaneous ways of feeding from the 16th day up to the end of lactation on the 39-43rd days: milk, chewed by mother food and firm forages. In social interactions cases of strict aggression are scarce. Dynamic socio-hierarchical structure of litters with the absence of stepped hierarchy is observed. As a whole, during the period of early ontogenesis strategy of the species provides the maximal survival of posterity instead of concurrence inside litters. Geographical differences in time frames of early ontogenesis, found when comparison of data from different regions, maybe caused both by intraspecific variation and peculiarities of local populations.

Diet shifting of tortoise-eating Golden Eagles (Aquila chrysaetos) in southeastern Bulgaria

Top predators may adapt their diets to changes in prey availability where human-induced environmental changes are intense. This long-term study of the breeding-season diet of Golden Eagle (Aquila chrysaetos) in the Strandzha Mountains analyzed shifts in diet caused by the population decline in principal prey species, the tortoises (Testudo hermanni and T. graeca). Tortoises comprised 50.0% of the eagle diet by prey number in the 1990s, but that share collapsed to 5.8% in 2014–2021. During this later interval, Golden Eagles preyed more intensively on lighter-weight prey such as Northern White-breasted Hedgehog (Erinaceus roumanicus, an increrase of 28.2% by number) and Edible Dormouse (Glis glis, an increase of 14.9% by number). Hedgehogs predominated in the diet of an individual eagle nest site for the first time in 1998 and became the principal prey in 2014–2021. Differences in food niche breadth and proportions of mesopredators between tortoise- and hedgehog-dominated individual annual diets were not significant, corresponding to a low level of food stress. The only eagle with an annual diet dominated by Squamata (snakes and lizards) was an exception, having the widest food niche. Young domestic ungulates have almost completely disappeared from eagle diets at the same as the reduction of tortoises, corresponding to a concurrent decline of livestock farming. The results obtained here have relevance to conservation management of both predator and prey populations.