Identification of potential chemosignals in the European water vole Arvicola terrestris.

The water vole Arvicola terrestris is endemic to Europe where its outbreak generates severe economic losses for farmers. Our project aimed at characterising putative chemical signals used by this species, to develop new sustainable methods for population control that could also be used for this species protection in Great Britain. The water vole, as well as other rodents, uses specific urination sites as territorial and sex pheromone markers, still unidentified. Lateral scent glands and urine samples were collected from wild males and females caught in the field, at different periods of the year. Their volatile composition was analysed for each individual and not on pooled samples, revealing a specific profile of flank glands in October and a specific profile of urinary volatiles in July. The urinary protein content appeared more contrasted as males secrete higher levels of a lipocalin than females, whenever the trapping period. We named this protein arvicolin. Male and female liver transcript sequencing did not identify any expression of other odorant-binding protein sequence. This work demonstrates that even in absence of genome, identification of chemical signals from wild animals is possible and could be helpful in strategies of species control and protection.

Fathers and sons: Physiological stress in male Zaisan mole voles, Ellobius tancrei.

The social environment can be stressful for at least some group members, resulting in elevated levels of glucocorticoid stress hormones (GC). Patterns of the relationships between social rank and GC levels vary between species. In carnivores, primates and birds that live in permanent cooperative groups, helpers do not usually display physiological indicators of stress. Very little is known about status-related GC differences within cooperative groups of rodents. In this laboratory study, we compared GC concentrations in dominant (fathers) and subordinate (natal sons) males of a cooperative subterranean vole, Ellobius tancrei. The assessment of adrenocortical activity by measuring urine glucocorticoid metabolites (UGM) was previously validated for this species through an ACTH challenge test. We observed clear peaks of UGM in the second or third urine samples taken after the administration of ACTH (lag time equal to 2.5-3 h). Thus, UGM is suitable to estimate physiological stress in Ellobius. Postpubertal sons living in natal groups had significantly higher UGM concentrations than their fathers. The average UGM levels of sons were positively associated with their ages and paternal body masses, and negatively associated with paternal ages. Hence, son-father interactions rather than just younger ages of sons appear to contribute to GC differences. The revealed pattern was not consistent with that reported for most cooperative species from other taxa, highlighting the importance of comparative studies.

Dimercaptopropane Sulfonate Chelation Affects In Vivo Hg and MeHg Distribution in Tissues and Urine of Prairie Voles (Microtus ochrogaster).

Methyl mercury cation (MeHg(+)) and divalent mercury (Hg(2+)) were quantified in urine, liver, kidney, and brain of prairie voles (Microtus ochrogaster) during a 12 week exposure to aqueous MeHg(+) at concentrations of 10, 100, and 1000 ng MeHg(+)/mL. Aqueous MeHg(+) exposures increased mercury accumulation in tissues of voles from each exposure group. Accumulation was greater within the higher two exposure groups. Similar [Hg(2+)] and [MeHg(+)] were determined within a given organ type before and after 2,3-dimercapto-1-propane sulfonate (DMPS) chelation. Similar correlations were seen for Hg(2+) and MeHg(+) concentrations in pre and post chelation urine. Post chelation urine more reliably predicted mercury species concentrations in tissues than did urine collected before chelation. These data demonstrate the utility of DMPS in noninvasive assessment of wildlife exposure to mercury, which may have utility in evaluating meta-population level exposure to hazardous wastes.

Ultraviolet sensitivity and colour vision in raptor foraging.

Raptors have excellent vision, yet it is unclear how they use colour information. It has been suggested that raptors use ultraviolet (UV) reflections from vole urine to find good hunting grounds. In contrast, UV plumage colours in songbirds such as blue tits are assumed to be 'hidden' communication signals, inconspicuous to raptors. This ambiguity results from a lack of knowledge about raptor ocular media transmittance, which sets the limit for UV sensitivity. We measured ocular media transmittance in common buzzards (Buteo buteo), sparrowhawks (Accipiter nisus), red kites (Milvus milvus) and kestrels (Falco tinnunculus) so that, for the first time, raptor UV sensitivity can be fully described. With this information, and new measurements of vole urine reflectance, we show that (i) vole urine is unlikely to provide a reliable visual signal to hunting raptors and (ii) blue tit plumage colours are more contrasting to blue tits than to sparrowhawks because of UV reflectance. However, as the difference between blue tit and sparrowhawk vision is subtle, we suggest that behavioural data are needed to fully resolve this issue. UV cues are of little or no importance to raptors in both vole and songbird interactions and the role of colour vision in raptor foraging remains unclear.

[Protein content in urine of male and female water vole (Arvicola amphibious) at the period of spring growth and sexual maturation].

The study was carried out on the captive bread water voles Arvicola amphibious kept in vivarium. At the first decade of January, March, and June, the body length and anogenital distance were measured, the body mass was determined, and urine was collected for determination of its protein content. The obtained results have shown that the protein content depends on sex of the animals and is connected with the reproductive status of males and their dimension-weight characteristics. The urinary protein excretion level in females remained stable at different months, whereas in males its sharp rise was noted at the period of spring growth and sexual maturation. The significant sexual differences were established in March and enhanced in June. In March the urine protein content in males was noted to correlate positively with the body mass and length and with the anogenital distance. The males reached sexual maturity at the earlier calendar terms than the females did; in sexually mature males the urine protein content was significantly higher than in the sexually immature ones.

Photoentrainment in blind and sighted rodent species: responses to photophase light with different wavelengths.

Our study examined the impact of daylight (photophase) wavelength on the photoentrainment sensitivity of two species with vastly different visual systems. Social voles (Microtus socialis) and 'blind' mole rats (Spalax ehrenbergi) were exposed to short-wavelength (479 nm) or long-wavelength (697 nm) light at an intensity of 293 µW cm(-2). Rhythms of urine production, urinary 6-sulfatoxymelatonin (6-SMT), urinary metabolites of adrenaline and cortisol, and oxygen consumption (VO(2)) were used as markers for the sensitivity of the photoentrainment system. Significant 24-h rhythms were detected in all variables for both species under short-wavelength light, whereas ultradian rhythms of 12- or 8-h were detected under long-wavelength light. Wavelength inversely affected 6-SMT levels in M. socialis (negative correlation) and S. ehrenbergi (positive correlation). Increased levels of stress hormone metabolites were detected in M. socialis under the long-wavelength light whereas, in S. ehrenbergi elevated levels were secreted under short-wavelength light. Long-wavelength light increased VO(2) in M. socialis and decreased it in S. ehrenbergi; short-wavelength light elicited the opposite effects. Our results indicate that photophase wavelength is an integral light property for modulating photoperiodic responses in mammals, including visually challenged species. Finally, the spectral-induced differential responses between the two species potentially represent adaptive physiological flexibility in species with contrasting visual and habitat challenges.

[Correlation between urine malondialdehyde level and males reproductive success in the water vole (Arvicola terrestris L.)].

The study was conducted in water vole (Arvicola terrestris L.) reared and bred in captivity. During the breeding season, voles were caged in heterosexual pairs for two weeks. If mating did not occur, new pairs were formed with unfamiliar partners. In the end of the breeding season, the individual male's reproductive characteristics were summarized, and the level of malondialdehyde (MDA) in their urine was assessed. As indicated by urine MDA concentration, the intensity of lipid peroxidation in males which could not became fathers was significantly higher than in fertile males. In the last group, the negative correlation between average numbers of pups in litter and urine MDA concentration was revealed. It is possible, that a causal factor of water vole males lowered fertility is oxidative stress.

Puumala hantavirus excretion kinetics in bank voles (Myodes glareolus).

Puumala hantavirus is present in bank voles (Myodes glareolus) and is believed to be spread mainly by contaminated excretions. In this study, we subcutaneously inoculated 10 bank voles with Puumala virus and sampled excretions until day 133 postinfection. Levels of shed viral RNA peaked within 11-28, 14-21, and 11-28 days postinfection for saliva, urine, and feces, respectively. The latest detection of viral RNA was 84, 44, and 44 days postinfection in saliva, urine, and feces, respectively. In contrast, blood of 5 of 6 animals contained viral RNA at day 133 postinfection, suggesting that bank voles secrete virus only during a limited time of the infection. Intranasal inoculations with bank vole saliva, urine, or feces were all infectious for virus-negative bank voles, indicating that these 3 transmission routes may occur in nature and that rodent saliva might play a role in transmission to humans.

Consumption of grass endophytes alters the ultraviolet spectrum of vole urine.

Fungal endophytes of grasses are known to benefit their hosts directly by increasing resistance to herbivores through mycotoxins. We propose and test assumptions of a novel hypothesis according to which fungal endophytes of grasses may benefit their hosts also indirectly by increasing the conspicuousness of a mammalian herbivore, the field vole (Microtus agrestis), to its avian predators by enhancing the ultraviolet visibility of vole urine. We found that field voles feeding on endophyte-infected meadow ryegrass (Lolium pratense) lost body mass, while voles feeding on non-infected meadow ryegrass gained mass. More interestingly, the maximum peak intensity of ultraviolet fluorescence in the urine of voles feeding on endophyte-infected grass shifted from over 380 nm to circa 370 nm, which is the suggested maximum sensitivity of the ultraviolet pigments in the eyes of vole-eating raptors. Therefore, grazing on endophyte-infected grass alters the ultraviolet spectrum of vole urine, thus potentially enhancing its visibility to avian predators.

Urinary adrenalin and cortisol secretion patterns of social voles in response to adrenergic blockade under basal conditions.

The effect of alpha(1)- and beta-adrenergic blockade on daily rhythms of urinary adrenalin (ADR) and cortisol (CORT) under basal conditions were evaluated. Voles acclimated to a 12:12 h light/dark cycle at 26+/-2 degrees C received a single dose of either propranolol (PROP; 4.5 mg/kg) or prazosin (PRAZ; 1 mg/kg) 1 h before lights off. Urine samples were collected for 24 h at 4 h intervals. PROP evokes a significant increase in mean urinary ADR; although CORT was unaffected by PROP, PRAZ administration significantly decreased both urinary ADR and CORT during the scotophase as compared with control voles. Cosinor analysis indicated a significant 24 h rhythm in urinary ADR, but not in CORT secretion. ADR mesor and amplitude were increased and acrophase was significantly delayed by 5 h in PROP-treated voles; PRAZ elicited opposite effects. Unexpectedly, these changes in the 24 h ADR rhythm persisted 4-weeks after PROP-treatment. The 24 h rhythm components of urinary CORT were marginally altered 4-weeks post-PROP, but only the acrophase showed a significant change. Collectively, the results indicate that sympathetic activity has a redundant compensatory mechanism defending against physiological changes induced by beta-blockade. The simultaneous decrease in adrenal hormones induced by PRAZ suggests that alpha(1)-adrenoceptors may contribute to the mechanism of integrated stress responses.

The effect of alpha- and beta-adrenergic blockade on daily rhythms of body temperature, urine production, and urinary 6-sulfatoxymelatonin of social voles Microtus socialis.

To examine the effect of adrenergic blockade on daily rhythms of rectal body temperature (T(b)), urine production rate, and melatonin (MEL; measured as urinary 6-sulfatoxymelatonin; 6-SMT), social voles Microtus socialis received a single intra-peritoneal injection of either prazosin (PRAZ, 1 mg/kg) or propranolol (PROP, 4.5 mg/kg); alpha- and beta-adrenergic blocking agents respectively, 1 h prior to scotophase onset (light/dark, 12L:12D; lights on 07:00 h). Both blockers caused significant decrease in T(b) values mainly during scotophase. Nocturnal urine production rates were higher for M. socialis treated with the drugs compared with controls. Overall, urine production rates were systematically higher in PROP-voles over the 24 h period when compared with PRAZ-voles; however these differences were not statistically significant. Interestingly, PROP caused significant elevation in urinary 6-SMT at the second half of the dark phase, whereas PRAZ had no effects. These data suggest that the mechanisms regulating MEL synthesis and thermoregulatory responses in M. socialis are different from those described in other rodents' species. Importantly, the data also suggest that the beta-blockade-induced elevation in MEL levels may be directly associated with increased urination in M. socialis.

NMR spectroscopy based metabonomic studies on the comparative biochemistry of the kidney and urine of the bank vole (Clethrionomys glareolus), wood mouse (Apodemus sylvaticus), white toothed shrew (Crocidura suaveolens) and the laboratory rat.

The metabolic profiles of three wild mammals that vary in their trophic strategies, the herbivorous bank vole (Clethrionomys glareolus), the granivorous wood mouse (Apodemus sylvaticus), and the insectivorous white-toothed shrew (Crocidura suaveolens), were compared with that of a widely used strain of laboratory rat (Sprague Dawley). In conjunction with NMR spectroscopic investigations into the urine and blood plasma composition for these mammals, high resolution magic angle spinning (HRMAS) 1H-nuclear magnetic resonance (NMR) spectroscopy was applied to investigate the composition of intact kidney samples. Adaptation to natural diet affects both renal metabolism and urinary profiles, and while these techniques have been used to study the metabolism of the laboratory rat little is known about wild small mammals. The species were readily separated by their urinary profiles using either crude metabolite ratios or statistical pattern recognition. Bank vole urine contained higher concentrations of aromatic amino acids compared with the other small mammals, while the laboratory rats produced relatively more hippurate. HRMAS 1H-NMR demonstrated striking differences in both lipid concentration and composition between the wild mammals and Sprague Dawley rats. Bank voles contained high concentrations of the aromatic amino acids phenylalanine, tyrosine and tryptophan in all tissue and biofluids studied. This study demonstrates the analytical power of combined NMR techniques for the study of inter-species metabolism and further demonstrates that metabolic data acquired on laboratory animals cannot be extended to wild species.