Apodemus Sylvaticus Research Articles

Aonchotheca annulosa and Aonchotheca murissylvatici, which is which? A reappraisal of the gastrointestinal Aonchotheca (Nematoda: Capillariidae) species common in wood mice and bank voles.

Aonchotheca annulosa and Aonchotheca murissylvatici, which is which? A reappraisal of the gastrointestinal Aonchotheca (Nematoda: Capillariidae) species common in wood mice and bank voles.

Comparative Phylogeography of Two Specialist Rodents in Forest Fragments in Kenya

The fragmented forests of the Kenya highlands, known for their exceptional species richness and endemism, are among the world’s most important biodiversity hotspots. However, detailed studies on the fauna of these ecosystems—especially specialist species that depend on moist forests, which are particularly threatened by habitat fragmentation—are still limited. In this study, we used mitochondrial genes (cytochrome b and the displacement loop) and a nuclear marker (retinol-binding protein 3) to investigate genetic and morphological diversity, phylogenetic associations, historical divergence, population dynamics, and phylogeographic patterns in two rodent species—the soft-furred mouse (Praomys jacksoni) and the African wood mouse (Hylomyscus endorobae)—across Kenya’s forest landscapes. We found a complex genetic structure, with P. jacksoni exhibiting greater genetic diversity than H. endorobae. The Mt. Kenya P. jacksoni populations are significantly genetically different from those in southwestern forests (Mau Forest, Kakamega Forest, and Loita Hills). In contrast, H. endorobae presented no observable biogeographic structuring across its range. The genetic diversity and geographic structuring patterns highlighted selectively strong effects of forest fragmentation and differing species’ ecological and evolutionary responses to these landscape changes. Our findings further underscore the need for expanded sampling across Kenya’s highland forests to better understand species’ changing diversity and distribution patterns in response to the impacts of human-mediated habitat changes. These insights are critical for informing conservation strategies to preserve biodiversity better in this globally important region.

Different life strategies of closely related louse species in sympatry: specialist and “generalist“ lineages of Polyplax serrata

The origin and significance of host specificity are intriguing questions in parasitology. In the case of single-host versus multiple-host parasites, this topic integrates with the concept of the specialist/generalist trade-off. We use the model of sucking lice Polyplax serrata and rodent hosts Apodemus, to address these concepts. Polyplax serrata was shown to form a complex genetic structure, with a strictly specific S lineage living on Apodemus flavicollis, and a less specific N lineage on A. flavicollis and Apodemus sylvaticus. Moreover, the S lineage formed two mitochondrial clades with geographically exclusive distributions and a narrow hybrid zone, providing an opportunity to test the hypothesis that hybrids suffer a decrease in fitness. We sampled 451 individual lice from two host species at 103 localities. We used prevalences and intensities as proxies of fitness, which the parasites realize on their host. The S lineage, strictly specific to Apodemus flavicollis, reached significantly higher prevalences and intensities on its host compared with the N lineage. Conversely, the N lineage occurred with high prevalence and intensity on A. sylvaticus but tended to use also A. flavicollis when the louse populations became too dense. We discuss possible mechanisms behind this difference (particularly interspecific competition as a typical phenomenon in the specialist/generalist systems). We conclude that a parasite’s “choice”, not accessibility of the host or interspecific competition, is the main factor affecting the louse prevalences. We suggest that historical differences in geographic distribution of both lice and mice may provide a possible explanation for the observed life strategy differences. In contrast to the convincing picture in S and N lineage prevalences, we did not detect an expected drop in fitness in hybrids. We consider instability of the hybrid zone, or decline in abundance of the respective hosts, as possible explanations for this result.

Mite composition in nests of the Japanese wood mouse, Apodemus speciosus (Rodentia: Muridae).

Acari is a diverse group of arthropods that include well-known parasites of animals. Rodents, particularly, serve as common hosts of mites and ticks, transmitting pathogens to domestic animals and humans. Understanding the ecological dynamics between parasites and rodent hosts is crucial for ecosystem management. Due to limited knowledge about the life history of ectoparasites in wild mouse nests, we collected four nests of Apodemus speciosus, the most common rodent species in the wild areas of Japan, along with soil samples near the nests to study arthropod communities. Mites overwhelmingly populated the mouse nests, comprising approximately 90% of all arthropods, while both mites and collembolans were prevalent in soil. Various species identified in our study, such as those from the families Laelapidae, Pygmephoridae, Cheyletidae, Trombiculidae, Glycyphagidae, and Thyrisomidae align with known ectoparasites or species found in the nests of other rodent species, but most parasitic species were never collected in the surrounding soil except for trombiculids. The dominance of mites in mouse nests suggests selective preference for inhabiting these host environments, although the exact reasons driving this dominance remain unclear. Further investigations into the food web within mouse nests will aid in characterising faunal composition and understanding the ecological interaction among rodents, mites, and other nest symbionts.

Wood Mice Utilize Understory Vegetation of Leafless Dead Dwarf Bamboo Culms as a Habitat and Foraging Site

Wood Mice Utilize Understory Vegetation of Leafless Dead Dwarf Bamboo Culms as a Habitat and Foraging Site

Seed Availability and Small Mammal Populations: Insights from Mediterranean Forests

Plant–animal interactions play a crucial role in ecosystem functioning, especially through seed dispersal mechanisms. Understanding how small mammal populations respond to seed availability is essential for ecosystem management and biodiversity conservation, especially in the context of habitat loss and climate change. We conducted a 10-year study in mixed Mediterranean oak–beech forests to investigate the population dynamics of common small mammal species in response to seed availability. Our findings revealed distinct responses among species, influenced by life history traits, foraging behaviour, and diet. Wood mice (Apodemus sylvaticus) showed a rapid population increase with seed availability both in the same year of seed fall and the following year, suggesting a flexible foraging strategy and a dependence on arboreal seed producers. Yellow-necked mice (Apodemus flavicollis) revealed immediate population increases in response to seed availability in the autumn, probably because of their arboreal habits and preference for exploiting seeds prior to maturation. Bank voles (Clethrionomys glareolus) showed responses with population peaks in years following high seed availability, indicating a slower demographic response to resource abundance. Surprisingly, the greater white-toothed shrew (Crocidura russula) responded indirectly to seed availability in Mediterranean forests, suggesting complex interactions with seed-associated invertebrates or dependence on other variables not considered. Our findings highlight the importance of understanding how changes in seed availability influence the population ecology of small mammals, with significant implications for the conservation and management of Mediterranean forest ecosystems in the context of climate change and recurrent droughts. These results emphasise the need to consider species interactions, resource availability, and climate change in the conservation and management of evolving ecosystems.

Trace metal accumulation through the environment and wildlife at two derelict lead mines in Wales

Trace metal pollution is globally widespread, largely resulting from human activities. Due to the persistence and high toxicity of trace metals, these pollutants can have serious effects across ecosystems. However, few studies have directly assessed the presence and impact of trace metal pollution across ecosystems, specifically across multiple environmental sources and animal taxa. This study was designed to assess the environmental health impacts of trace metal pollution by assessing its extent and possible transfer into wildlife in the areas surrounding two abandoned metalliferous mine complexes in Wales in the UK. Water, sediment, and soil at the mine sites and in areas downstream had notably elevated concentrations of Pb, Zn, and, to a lesser extent, Cd and Cu, when compared to nearby control sites. These high trace metal concentrations were mirrored in the body burdens of aquatic invertebrates collected in the contaminated streams both at, and downstream of, the mines. Wood mice collected in contaminated areas appeared to be able to regulate their Zn and Cu tissue concentrations, but, when compared to wood mice from a nearby control site, they had significantly elevated concentrations of Cd and, particularly, Pb, detected in their kidney, liver, and bone samples. The Pb concentrations found in these tissues correlated strongly with local soil concentrations (kidney: ρ = 0.690; liver: ρ = 0.668, bone: ρ = 0.649), and were potentially indicative of Pb toxicity in between 10 % and 82 % of the rodents sampled at the mine sites and in areas downstream. The high trace metal concentrations found in the environment and in common prey species (invertebrates and rodents) indicates that trace metal pollution can have far-reaching, ecosystem-wide health impacts long after the polluting activity has ceased, and far beyond the originating site of the pollution.

Угруповання мишовидих гризунів на ділянках з різним ступенем ураження пожежами: чорнобильські полігони

As a result of climate change, forest fires are becoming a common factor in the dynamics of ecosystems in the forest zone of Ukraine, but the assessment of the consequences of this shift in the ecological situation is in the process of pilot studies. In the spring of 2020, a number of large ecosystem fires occurred in the Central Polissia region, which affected forests the most. Among other things, a large fire occurred in ecosystems located in the Exclusion Zone and the Zone of Unconditional (Mandatory) Resettlement, which was formed as a result of the Chornobyl accident. The ecosystems of the Chornobyl Radiological and Ecological Biosphere Reserve located within its boundaries were also affected by the fire. The consequences of this fire were assessed a year later, using mouse-like rodents as a model group. The purpose of the study was to assess and compare the communities of mouse-like rodents in areas that were affected by two degrees of fire damage—where there was a surface fire and those that were most affected (highland fire). Four polygons were created in the control-impact scheme. Each of the pairs of plots was identical in terms of typical forest vegetation conditions. Sherman traps were used for trapping. A total of 560 trap-days were processed, and 101 animals were captured. The presence of four species of rodents from the genera Apodemus, Sylvaemus, and Myodes was recorded, namely the striped field mouse, the yellow-necked wood mouse, the European wood mouse, and the bank vole. The main indicators of species diversity were calculated using information indices—species richness, evenness, and similarity. The surveys revealed both negative and positive changes in areas affected by fires. Areas characterised by relatively higher values of species diversity indices compared to the control had a high intensity of vegetation recovery. They belonged to areas with wet, relatively fertile (sugrud) and infertile (subor) forest types. The plots with low intensity of vegetation recovery had a depleted community structure and belonged to fresh and dry boreal forest. Based on this, it is possible to create a forecast of ecosystem restoration by assessing the type of forest vegetation conditions.

Camera traps equipped with macro lenses as a tool for monitoring arboreal small mammals: a case study in an agroecosystem (NE Italy)

Despite their increasing use, camera traps as a monitoring tool for arboreal small mammals leave room for further improvements to increase their effectiveness. In the summer of 2023, we conducted a small mammal survey in a wooded area of a lowland agroecosystem in the Veneto region, using standard camera traps equipped with macro lenses for close-up shooting. This camera trap technique made it possible to contact three species of small mammals in the tree-shrub layer: Eurasian red squirrel Sciurus vulgaris, wood mouse Apodemus sylvaticus, and black rat Rattus rattus. The use of macro lenses combined with the standard camera trapping technique made it possible to obtain better quality images and more information even on smaller species compared to more traditional camera traps.

Small mammal assemblages in heterogeneous landscapes at the Southern tip of Italian peninsula evidence clear eco-biogeographic patterns

We investigated the frequencies of sympatric small mammal species in 12 habitat-types located in the extreme south of the Italian peninsula (Calabria) using trapping techniques. Ten species were detected with Apodemus sylvaticus, the most abundant species. The assemblages of small mammal species recorded in the 12 selected habitat types revealed clear ecological and biogeographical patterns in the extreme southern tip of the Italian peninsula. Ecologically, we observed a clear dissimilarity between a guild of species linked to thermo-xerophilous habitat types and a comparable guild of mesophilous species linked to forest and sciaphilous habitat types. The differences among communities inhabiting in different habitat types also emerged in rarefaction curves, DCA analysis and Whittaker plots. Thus, all these sets of analyses were consistent in their interpretation of the variation of small mammal community structure along the gradient (β-diversity) among habitat types. From a biogeographical point of view, this is an apparent expression of a clear North–South gradient pattern that was already observed at the species level with Calabria being characterized by a strong impoverishment in species’ richness and diversity (“peninsula effect”). However, this rationale has been based so far on indirect data of small mammals preyed upon and recorded in owl’s pellets: the fact that a similar pattern was obtained also using small mammals recorded by traps indicates that the results were robust and generalizable. Ecological factors at the local scale and biogeographical factors at the peninsular scale could explain the community patterns that we observed in the present study.

Disentangling the Effects of Climate and Land Uses on Small Mammals in Agroecosystems of NE Spain

We analyzed the two main drivers (climate and land uses) shaping the composition of small mammal communities at 16 localities situated in the confluence of the Mediterranean and Eurosiberian regions (Barcelona, Spain). The study area represents a land use and land cover gradient showing urbanization and crop intensification in the lowlands and forest encroachment in mountain areas. We identified 2458 small mammal individuals of 12 different species from barn owl (Tyto alba) pellets. Three open-land species (Microtus duodecimcostatus, Crocidura russula, and Mus spretus) and one forest/generalist species (Apodemus sylvaticus) were dominant in the diet, accounting for 93% of prey. In order to disentangle the effects of both main drivers on the small mammal community, we used partial constrained ordination techniques, which allowed us to determine the pure effects (and shared effects) of the environmental factors. Land use predictors explained 33.4% of the variance (mostly crops), followed by 23.4% of the variance explained by the geo-climatic variables (mostly rainfall), and an additional 24.8% of the variance was shared by both groups of predictors, totaling 81.6% of environmental variance. The remaining 18.4% of variance was unexplained by environmental matrices. This pattern was consistent with expected associations of species and biotic influences at small spatial scales and highlighted that the number of species increased from the crops in the lowlands towards the highlands covered by deciduous and coniferous forests.

Rapid genotyping of Toxoplasma gondii isolates via Nanopore-based multi-locus sequencing

Toxoplasma gondii is an obligate intracellular parasite associated with severe disease, especially in the immunosuppressed. It is also a cause of congenital malformation and abortion in both animals and humans and is considered one of the most important foodborne pathogens worldwide with different strains showing variable distribution and differing pathogenicity. Thus, strain-level differentiation of T. gondii isolates is an essential asset in the understanding of parasite’s diversity, geographical distribution, epidemiology and health risk. Here, we designed and implemented an Oxford Nanopore MinION protocol to analyse genomic sequence variation including single nucleotide polymorphisms (SNPs) and insertion/deletion polymorphisms (InDel’s) of four different genomic loci, part of protein coding genes SAG2, SAG3, ROP17 and ROP21. This method provided results with the sequencing depth necessary for accurate differentiation of T. gondii strains and represents a rapid approach compared to conventional techniques which we further validated against environmental samples isolated from wild wood mice. In summary, multi-locus sequence typing (MLST) of both highly conserved and more polymorphic areas of the genome, provided robust data for strain classification in a platform ready for further adaption for other strains and pathogens.

WILDbase: towards a common database to improve wildlife disease surveillance in Europe.

BackgroundTo be better prepared for emerging wildlife-borne zoonoses, we need to strengthen wildlife disease surveillance.AimThe aim of this study was to create a topical overview of zoonotic pathogens in wildlife species to identify knowledge gaps and opportunities for improvement of wildlife disease surveillance.MethodsWe created a database, which is based on a systematic literature review in Embase focused on zoonotic pathogens in 10 common urban wildlife mammals in Europe, namely brown rats, house mice, wood mice, common voles, red squirrels, European rabbits, European hedgehogs, European moles, stone martens and red foxes. In total, we retrieved 6,305 unique articles of which 882 were included.ResultsIn total, 186 zoonotic pathogen species were described, including 90 bacteria, 42 helminths, 19 protozoa, 22 viruses and 15 fungi. Most of these pathogens were only studied in one single animal species. Even considering that some pathogens are relatively species-specific, many European countries have no (accessible) data on zoonotic pathogens in these relevant animal species. We used the Netherlands as an example to show how this database can be used by other countries to identify wildlife disease surveillance gaps on a national level. Only 4% of all potential host-pathogen combinations have been studied in the Netherlands.ConclusionsThis database comprises a comprehensive overview that can guide future research on wildlife-borne zoonotic diseases both on a European and national scale. Sharing and expanding this database provides a solid starting point for future European-wide collaborations to improve wildlife disease surveillance.

Higher exploratory and vigilant behaviors related to higher central dopaminergic activities of Formosan wood mice (Apodemus semotus) in light-dark exploration tests

Formosan wood mice (Apodemus semotus) are endemic rodents in Taiwan. Recently Formosan wood mice exhibit similar locomotor behaviors in the laboratory environment as in the field environment has shown. Contemporaneously, Formosan wood mice have higher moving distances of and central dopaminergic (DAergic) activities than C57BL/6 mice in behavioral test. This study tried to compare the behavioral responses between male Formosan wood mice and male C57BL/6 mice in the light-dark exploration tests. We also measured the levels of DA and 3,4-dihydroxyphenylacetic acid (DOPAC), the primary metabolite of DA, to assess the dopaminergic activity of the medial prefrontal cortex, striatum, and nucleus accumbens. Our data show that Formosan wood mice revealed higher exploration and central DAergic activities than did C57BL/6 mice in the light-dark exploration tests, and diazepam (an anxiolytics) treatment reduced the exploratory activity and central dopaminergic activities in Formosan wood mice, but not in C57BL/6 mice. After repeated exposure to light-dark exploration tests, the latency to dark zone was increased, and the duration in light zone as well as the central DAergic activity were decreased in C57BL/6 mice. This study provides comparative findings; Formosan wood mice showed the higher exploratory activities than C57BL/6 mice did, and their central DAergic activities were related to the behavioral responses in these two mice. This could potentially shed light on the reasons behind the prevalence of higher exploration and central dopaminergic activities. Using Formosan wood mice as a model to study human diseases related to hyperactivity adds significant value to the potential research.

Social and environmental transmission spread different sets of gut microbes in wild mice

Gut microbes shape many aspects of organismal biology, yet how these key bacteria transmit among hosts in natural populations remains poorly understood. Recent work in mammals has emphasized either transmission through social contacts or indirect transmission through environmental contact, but the relative importance of different routes has not been directly assessed. Here we used a novel radio-frequency identification-based tracking system to collect long-term high-resolution data on social relationships, space use and microhabitat in a wild population of mice (Apodemus sylvaticus), while regularly characterizing their gut microbiota with 16S ribosomal RNA profiling. Through probabilistic modelling of the resulting data, we identify positive and statistically distinct signals of social and environmental transmission, captured by social networks and overlap in home ranges, respectively. Strikingly, microorganisms with distinct biological attributes drove these different transmission signals. While the social network effect on microbiota was driven by anaerobic bacteria, the effect of shared space was most influenced by aerotolerant spore-forming bacteria. These findings support the prediction that social contact is important for the transfer of microorganisms with low oxygen tolerance, while those that can tolerate oxygen or form spores may be able to transmit indirectly through the environment. Overall, these results suggest social and environmental transmission routes can spread biologically distinct members of the mammalian gut microbiota.

The effect of forest structural complexity on tick-borne pathogens in questing ticks and small mammals

Forest management is increasingly focused on enhancing structural complexity. An increase in structural complexity is assumed to increase the abundance and diversity of fauna, including vertebrates. This faunal assemblage serves, in turn, as host community for a suite of vectors and their pathogens, so that structural complexity may cascade through a network of interactions in forest ecosystems. Here we use a network of 19 forest plots representing a gradient of structural complexity and dominant tree species (oak, beech, poplar) to test two hypotheses on the effect of structural complexity on the prevalence of tick-borne pathogens. Our first hypothesis is that tick densities will increase with increasing structural complexity, assuming that each life stage has higher chances of finding a suitable host. The second hypothesis is that the pathogen prevalence in ticks and small mammals decreases (cf. dilution hypothesis) or increases (cf. amplification hypothesis) with increasing structural complexity. These expectations are tested through a community-level analysis, looking at twelve pathogens: seven genospecies of Borrelia (B. afzelii, B. bavariensis, B. garinii, B. burgdorferi sensu stricto, B. spielmanii, B. valaisiana and B. miyamotoi), Babesia s.s., Babesia microti, Anaplasma phagocytophilum, Rickettsia helvetica and Spiroplasma ixodetes. We found that more structurally complex forests have a higher density of questing nymphs (in June and July, during the peak of nymph activity). We did not find a clear change in pathogen prevalence with increasing structural complexity in ticks, wood mice and bank vole; the effect was different for the different pathogens and between the different dominant tree species. No clear co-occurrence patterns of pathogens were found. The density of infected nymphs and thus the disease risk is higher in more complex forests. A potential solution is to focus on decreasing the human-tick interactions in forests instead of trying to decrease the number of questing ticks.

The impact of within-host coinfection interactions on between-host parasite transmission dynamics varies with spatial scale.

Within-host interactions among coinfecting parasites can have major consequences for individual infection risk and disease severity. However, the impact of these within-host interactions on between-host parasite transmission, and the spatial scales over which they occur, remain unknown. We developed and apply a novel spatially explicit analysis to parasite infection data from a wild wood mouse (Apodemus sylvaticus) population. We previously demonstrated a strong within-host negative interaction between two wood mouse gastrointestinal parasites, the nematode Heligmosomoides polygyrus and the coccidian Eimeria hungaryensis, using drug-treatment experiments. Here, we show this negative within-host interaction can significantly alter the between-host transmission dynamics of E. hungaryensis, but only within spatially restricted neighbourhoods around each host. However, for the closely related species E. apionodes, which experiments show does not interact strongly with H. polygyrus, we did not find any effect on transmission over any spatial scale. Our results demonstrate that the effects of within-host coinfection interactions can ripple out beyond each host to alter the transmission dynamics of the parasites, but only over local scales that likely reflect the spatial dimension of transmission. Hence there may be knock-on consequences of drug treatments impacting the transmission of non-target parasites, altering infection risks even for non-treated individuals in the wider neighbourhood.

Adiaspiromycoses in Wild Rodents from the Pyrenees, Northeastern Spain.

Adiaspiromycosis is a nontransmissible infectious pulmonary disease caused by the inhalation of propagules from fungal species belonging to the family Ajellomicetaceae, especially Emergomyces crescens. Adiaspiromycosis caused by E. crescens has been recorded in a broad number of species worldwide, with small burrowing mammals being considered the main hosts for this environmental pathogen. Only a handful of studies on adiaspiromycosis in European wildlife has been published to date. We assessed the occurrence of adiaspiromycosis in wild rodents (Murinae and Arvicolinae) from the central Spanish Pyrenees (NE Spain). The lungs of 302 mice and 46 voles were screened for the presence of adiaspores through histopathologic examination. Pulmonary adiaspiromycosis was recorded in 21.6% of all individuals (75/348), corresponding to 63/299 wood mice (Apodemus sylvaticus) and 12/40 bank voles (Myodes glareolus). Adiaspore burden varied highly between animals, with a mean of 0.19 spores/mm2 and a percentage of affected lung tissue ranging from <0.01% to >8%. These results show that the infection is present in wild rodents from the central Spanish Pyrenees. Although the impact of this infection on nonendangered species is potentially mild, it might contribute to genetic diversity loss in endangered species.

Assessment of the Current State of the Hissar High-Mountain Natural Plague Focus in the Republic of Tajikistan

The review is devoted to discussing the results of survey in the Hissar high-mountain natural plague focus on the territory of the Republic of Tajikistan in 2015–2023. Regular examination of the focus was carried out in 1970–1991. According to its results, the main carrier of the plague pathogen was the juniper vole, in the population of which a strain of the non-main subspecies central asiatica (0.PE4) of Hissar biovar (0.PE4h) was steadily circulating, the strain considered avirulent for humans. During that period, 853 strains were isolated in the focus, of which 799 (93.7%) were from the juniper vole and its fleas. Secondary carriers – the silver vole, the pygmy wood mouse, and the gray hamster – were rarely involved in epizootics. The red marmot, which has epidemiological significance due to its hunting by the local population, occupies a special position in the focus. Socio-political phenomena at the end of the 20th – early 21st century caused a long break in the work of the Tajik Plague Control Station. In 2008, the Station was transformed into the Republican Center for Combating Quarantine Diseases under the Ministry of Health and Social Protection of the Population of the Republic of Tajikistan. In 2015, studies were resumed, but carried out on a small scale. In 2021–2023, epizootiological monitoring in the Hissar focus was performed jointly with Russian specialists with the testing of field material samples for plague and other natural-focal infections. Currently, against the background of low numbers and population density of small mammals and their blood-sucking ectoparasites – potential carriers and vectors of zoonoses – the circulation of agents of plague, tularemia, pseudotuberculosis, tick-borne viral encephalitis, Ixodidae tick-borne borreliosis, human granulocytic anaplasmosis, human monocytic ehrlichiosis has not been registered. Markers (DNA) of causative agents of leptospirosis and intestinal yersiniosis have been identified. Joint Tajik-Russian cooperation on issues of ensuring the epidemiological well-being of the population of the Republic of Tajikistan must be continued.

Human urine does not protect acorns against predation by the wood mouse (Apodemus sylvaticus): a field study with video recording

Direct seeding is a revegetation method that can offer great advantages for forest restoration, but suffers the drawback of seed loss due to granivorous rodents. Thus, to make direct seeding a useful and scalable forest restoration method, we need to find ways to protect seeds against rodents. Scents produced by carnivorous or omnivorous animals that elicit a fear response on rodents are a promising group of substances that can be used to protect seeds and that have demonstrated effectiveness in a number of cases. Here, I test if human urine has a protective effect on Holm oak (Quercus ilex) acorns against predation by mice. Human urine would be much easier and cheaper to obtain than the urine of other animals, providing the possibility, if effective, to scale the application of a repellent substance. I set up a field experiment in an area with high wood mouse (Apodemus sylvaticus) abundance and used eight urine donors. Neither urine nor donor had any effect. Acorn removal was very fast and high, reaching 97.2% after 7 days. Video recording with camera traps showed that the wood mouse was the main predator, but the Eurasian jay also removed acorns. I conclude that human urine is not useful as a repellent against mice and suggest to focus efforts in finding other substances to repel seed predators.