Degradative succession of the insects in small rodents in subtropical systems

We evaluated the insect succession in small rodent carcasses on the soil extracts (surface vs. buried) in two areas (riparian vs. agricultural) and two seasonal periods (spring vs. summer). Daily, the rodent carcasses were weighed and the insects present were collected in them for counting and family level identification. We also measured the air and soil temperature daily, in addition to the physical and chemical characteristics of the soil. The total of 11,059 individuals from 28 taxa was collected. The most abundant taxa were Calliphoridae (70%), Formicidae (20%), Muscidae (2%), and Sarcophagidae (2%). Insect richness was higher in spring in riparian vegetation areas; however, decomposition and insect abundance were greater in spring in agricultural areas by the high temperature measured. Vespidae, Sarcophagidae, Muscidae, and Calliphoridae decreased over time with abundance peaks respectively at 3, 7, 7, and 8 days in riparian vegetation areas. Calliphoridae decreased abundance over time with a peak at five days, but Armadillidiidae increased with peak at 6-9 days in agricultural areas. Decay and insect abundance was high in agricultural areas, mainly on the soil surface. Insect richness was high in riparian vegetation areas, especially on the soil surface. Only the superficial layers of soil presented taxon indicators and all decreased over time with abundance peaks of Calliphoridae, Sarcophagidae, and Muscidae at 5-8, 7, and 7 days, respectively. This abundance peak of insect families help to understand the degradative succession of the insect community in small rodents in subtropical systems of the neotropical region.

Mammal fauna of Chisinau airport, Republic of Moldova

Introduction. Airport territories are large, containing a high variety of biotopes, mostly open type, and are relatively protected against intense human activity, thus creating favorable conditions for many mammal species that serve as trophic source for many bird species. Material and methods. The studies were performed during 2012-2014 on the territory of Chisinau airport and within the adjacent ecosystems. The mammals were recorded by direct observations, based on traces and trophic activity on routes ranging from 1 to 3 km. The small mammals were assessed with traps. The bat species were identified according to their flight pattern and using the ultrasound detector. Results. In the airport, 31 species of mammals were registered: 5 insectivore species, 7 bat species, 14 rodent species, 1 hare species and 4 carnivorous species. The most widespread, common and abundant were the rodents and the fox. Among small rodent species, the most abundant was Apodemus sylvaticus with 51.6%, followed by the Microtus arvalis (38.9%), while on the airport grassland, the field vole dominated with more than 60%. The diet of Athene noctua included predominantly Mus musculus with over 51%, followed by M. arvalis with 23.7%. 7 species are rare and 5 protected – bicolor shrew and 4 bat species. Conclusions. The airport territory and adjacent ecosystems provide favorable conditions for many mammal species. The presence of rodents favors the occurrence of rather high number of prey birds, which represent a threat for the safety of aircraft flights. The fox can pose direct threat to flight safety.

Influence des perturbations anthropiques sur les communautés de petits mammifères des savanes gabonaises

Les savanes gabonaises connaissent des feux anthropiques récurrents, entraînant des dommages sur cet écosystème. L’influence de ce facteur sur la diversité des micromammifères n’a jamais été étudiée. Une situation préoccupante pour ce taxon qui fait l’objet de très peu de programmes de protection. A travers l’analyse de la distribution spatiale des espèces (Muridés), l’étude vise à mesurer l’empreinte écologique des activités anthropiques dans trois régions du Gabon, présentant des niveaux de perturbations différents. Au total 259 individus appartenant à six espèces de muridés ont été capturés avec un effort de 6220 nuit-pièges. Les rendements de capture varient de 0,5 à 15%. Mus minutoides (62,5%) et Lemniscomys striatus (28.9%) sont les plus abondantes. La richesse spécifique (S) varie de 1 à 4 espèces dans les savanes post -feu, alors qu’elle est de 5 dans les savanes protégées des feux, et de 2 espèces dans les savanes fauchées puis brulées. La diversité la plus élevée a été observée dans les savanes non exposées au feu (H’= 1,10 ; J= 0,68). Ceci atteste que le feu influe sur l’abondance, et lorsqu’il est préalablement associé à la fauche, il agirait à la fois sur la diversité et sur l’abondance d’espèces locales. English title: Influence of human disturbance to the small mammal communities in the Gabonese savannahs In the issue of the use of recurrent fires in Gabon, we carried out an inventory both in the Gabonese savannahs that are regularly burned and in those that are not. The study was carried out in the southern and central savannahs of Gabon during the periods from 2004, 2012 and 2013. A total of 259 individuals representing six species of small savannah rodents were captured over 6,220 trap nights. Trap success was variable (0.5 to 15%). Mus minutoides (62.5%) and Lemniscomys striatus (28.9%) are the most abundant. Small rodent abundance was significantly higher in the savannahs protected from fires. The species richness varies from 1 to 4 species in the post-fire savannahs and up to 5 species in the savannahs protected from fires. The savannahs that were mowing prior to burning have yielded only 2 species. The highest diversity index (H’) is found in savannahs not exposed to fire (H’= 1.10). Bush fires seem to have a direct effect on species abundance. Conversely, when savannahs are mown prior to burning, both the diversity and abundance of local species communities are affected. This study gave an initial idea of the diversity of the rodent population in this the recurrent use to fires.

A beacon of dung: using lemming (Lemmus lemmus) winter nests and DNA analysis of faeces to further understand predator–prey dynamics in Northern Sweden

The hypothesis that predation is the cause of the regular small rodent population oscillations observed in boreal and Arctic regions has long been debated. Within this hypothesis, it is proposed that the most likely predators to cause these destabilizing effects are sedentary specialists, with small mustelids being possible candidates. One such case would be the highly specialized least weasel (Mustela nivalis) driving the Norwegian lemming (Lemmus lemmus) cycle in Fennoscandia. These predators are often elusive and therefore distribution data can only be based on field signs, which is problematic when various mustelid species are sympatric, such as weasels and stoats (Mustela erminea). Here we present the results of using mustelid faeces in predated winter lemming nests to correctly identify the predator and thus discern which species exerts the strongest predation pressure on lemming winter populations. Samples were obtained during different phases in the lemming cycle, spanning 6 years, to account for different prey densities. Faecal mitochondrial DNA extraction and amplification of a 400-bp fragment was successful in 92/114 samples (81%); the sequencing of these samples proved that most predation occurrences (83%) could be attributed to the least weasel. These findings support the hypothesis that weasels in particular show high specificity in predation and could therefore be candidates to driving the lemming cycle in this area. We conclude that DNA analysis of faecal remains around predated nests can be a useful tool for further investigations concerning predator–prey interactions in the tundra.

Structure of small rodent communities in orchards from the central part of the Republic of Moldova and Bacau district, Romania

The studies were performed in the period 2008-2015 in orchards from the central part of the Republic of Moldova and Bacău County, Romania. In both areas 12 species rodent were registered, of which in central Moldova orchards the species R. norvegicus and P. subterraneus were not registered, while in Bacau orchards the species A. uralensis, M. rossiaemeridionalis and D. nitedula weren’t recorded. In CM orchards the dominant species was M. rossiaemeridionalis with about 30%, followed by A. sylvaticus and A. flavicollis. In BC orchards the dominant species was A. flavicollis with more that 41%, followed by A. sylvaticus and M. arvalis.The analysis of demographic structure in spring period showed a high proportion of reproductive females in all species, being the highest at M. rossiaemeridionalis in CM orchard and in A. flavicollis in BC orchard. The share of young individuals constituted up to 40% depending on the species being the highest at M. rossiaemeridionalis in CM orchard and in A. flavicollis in BC orchard. A significant difference in the area of the individual sectors of M.rossiaemeridionalis males and females in the orchard in summer (t = 3.46) and autumn (t = 3.39) was established, as well as for A. sylvaticus in the spring and summer period (t = 2.06; 2.03), and for A.uralensis in spring and autumn (t = 2.99; 3.44).

Prevalence of Hantaviruses Harbored by Murid Rodents in Northwestern Ukraine and Discovery of a Novel Puumala Virus Strain

In Europe, two species of hantaviruses, Puumala orthohantavirus (PUUV) and Dobrava orthohantavirus (DOBV), cause hemorrhagic fever with renal syndrome in humans. The rodent reservoirs for these viruses are common throughout Ukraine, and hence, the goal of this study was to identify the species and strains of hantaviruses circulating in this region. We conducted surveillance of small rodent populations in a rural region in northwestern Ukraine approximately 30 km from Poland. From the 424 small mammals captured, we identified nine species, of which the most abundant were Myodes glareolus, the bank vole (45%); Apodemus flavicollis, the yellow-necked mouse (29%); and Apodemus agrarius, the striped field mouse (14.6%) Using an indirect immunofluorescence assay, 15.7%, 20.5%, and 33.9% of the sera from M. glareolus, A. glareolus, and A. flavicollis were positive for hantaviral antibodies, respectively. Additionally, we detected antibodies to the hantaviral antigen in one Microtus arvalis, one Mus musculus, and one Sorex minutus. We screened the lung tissue for hantaviral RNA using next-generation sequencing and identified PUUV sequences in 25 small mammals, including 23 M. glareolus, 1 M. musculus, and 1 A. flavicollis, but we were unable to detect DOBV sequences in any of our A. agrarius specimens. The percent identity matrix and Bayesian phylogenetic analyses of the S-segment of PUUV from 14 M. glareolus lungs suggest the highest similarity (92–95% nucleotide or 99–100% amino acid) with the Latvian lineage. This new genetic information will contribute to future molecular surveillance of human cases in Ukraine.

Small rodent cycles influence interactions among predators in a boreal forest ecosystem

Cyclic fluctuations of prey have profound effects on the functioning of ecosystems, for example, by changing the dynamics, behavior, and intraguild interactions of predators. The aim of this study was to assess the effect of rodent cyclic fluctuations in the interspecific interactions of a guild of small- and medium-sized predators: red fox (Vulpes vulpes), pine marten (Martes martes), and weasels (Mustela erminea and Mustela nivalis) in the boreal ecosystem. We analyzed eight years (2007–2014) of snow tracking data from southeastern Norway using structural equation models to assess hypothesized networks of causal relationships. Our results show that fluctuations in rodent abundance alter the strength of predator’s interactions, as well as the effect of determinant environmental variables. Pine marten and weasel abundances were positively associated with rodent population growth rate, but not red fox abundance. All predators were positively associated with each other; however, the association between red fox and the other predators weakened when rodents increased. Rodent fluctuations had variable effects on the habitat use of the predators. The presence of agricultural land was important for all predators, but this importance weakened for the mustelids as rodent abundance increased. We discuss the shifting role of interference and exploitative competition as possible mechanisms behind these patterns. Overall, we highlight the importance of accounting for the dynamics of prey resources when studying interspecific interactions among predators. Additionally, we demonstrate the importance of monitoring the predator populations in order to anticipate undesirable outcomes such as increased generalist predator abundances to the detriment of specialists.

Real-Time PCR for Molecular Detection of Zoonotic and Non-Zoonotic Giardia spp. in Wild Rodents

Giardiasis in humans is a gastrointestinal disease transmitted by the potentially zoonotic Giardia duodenalis genotypes (assemblages) A and B. Small wild rodents such as mice and voles are discussed as potential reservoirs for G. duodenalis but are predominantly populated by the two rodent species Giardia microti and Giardia muris. Currently, the detection of zoonotic and non-zoonotic Giardia species and genotypes in these animals relies on cumbersome PCR and sequencing approaches of genetic marker genes. This hampers the risk assessment of potential zoonotic Giardia transmissions by these animals. Here, we provide a workflow based on newly developed real-time PCR schemes targeting the small ribosomal RNA multi-copy gene locus to distinguish G. muris, G. microti and G. duodenalis infections. For the identification of potentially zoonotic G. duodenalis assemblage types A and B, an established protocol targeting the single-copy gene 4E1-HP was used. The assays were specific for the distinct Giardia species or genotypes and revealed an analytical sensitivity of approximately one or below genome equivalent for the multi-copy gene and of about 10 genome equivalents for the single-copy gene. Retesting a biobank of small rodent samples confirmed the specificity. It further identified the underlying Giardia species in four out of 11 samples that could not be typed before by PCR and sequencing. The newly developed workflow has the potential to facilitate the detection of potentially zoonotic and non-zoonotic Giardia species in wild rodents.

Larazotide Acetate: A Pharmacological Peptide Approach to Tight Junction Regulation

Larazotide acetate (LA) is a single-chain peptide of eight amino acids that acts as a tight junction regulator to restore intestinal barrier function. LA is currently being studied in phase 3 clinical trials and is orally administered to adult patients with celiac disease as an adjunct therapeutic to enhance intestinal barrier function that has been disrupted by gliadin-induced immune reactivity. Mechanistically, LA is thought to act as a zonulin antagonist to reduce zonulin-induced increases in barrier permeability and has been associated with the redistribution and rearrangement of tight junction proteins and actin filaments to restore intestinal barrier function. More recently, LA has been linked to inhibition of myosin light chain kinase, which likely reduces tension on actin filaments, thereby facilitating tight junction closure. Small (rodent) and large (porcine) animal studies have been conducted that demonstrate the importance of LA as a tight junction regulatory peptide in conditions other than celiac disease, including collagen-induced arthritis in mice and intestinal ischemic injury in pigs.

Evaluation of bioconcentration of trace elements in the Western Mediterranean mouse (Mus spretus Lataste, 1883) at two Moroccan wetland sites

Many micromammals were shown to be vulnerable to metallic trace elements and are therefore suitable for biomonitoring. The objective of our research is to assess the exposure of a small rodent, Mus spretus, as a bioindicator of pollution to trace elements. We have determined the concentrations of Cu, Pb, Cr, Zn and Fe in the liver, kidneys and heart of 71 individuals of Mus spretus in north-west Morocco in two areas: Merja Zerga and Dayet Erroumi. Tissue metal concentrations in this species varied widely with age, sex, sites and organs. The concentration of Cu in the liver was the highest among all the metals and was recorded in adult females of Merja Zerga with a maximum of 60 µg / g ; at Dayet Erroumi, it was around 14 µg / g. At the same time, we found a similar trend for Fe, Pb, Cr and Zn in the three organs in males and females at the two sites. Highly significant differences between females at the two sites were recorded for the variables weight (W) and head to body length (TL) (t = -3.992; p < 0.001 and t = -2.242, p < 0.05), however, males obtained equal values ​​in the two sites. Spatiotemporal monitoring in small mammals must be studied, but requires the application of a non-lethal estimator.