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12. Integumentary odoriferous glands in Meriones libycus

Creator:
Djeridane, Yasmina, Zima, Jan, Griffiths, Huw I., Burda, Hynek, and Sedláček, František
Type:
article and TEXT
Subject:
integumentary odoriferous gland, gerbil, histology, and scent-related behavior
Language:
English
Description:
Macroscopic and histological examinations of the integument demonstrate that Meriones libycus possesses a varied assortment of skin scent-glands: alveolar sebaceous holocrine mouth corner gland; branched tubulo-acinar sero-mucous merocrine gular gland; sudoriferous merocrine palmar and plantar glands; alveolar sebaceous holocrine abdominal gland and alveolar sebaceous holocrine preputial and clitorial glands. Related behavior observations on captive animals in laboratory conditions, demonstrate that this species has several patterns of scent emission and marking: the mouth-corner glands, pressed and rubbed by the forepaws, are apparently involved in individual recognition via naso-oral contacts. Runways and movements are perhaps scent-marked environment with plantar and palmar secretions. The transfer of scent from the site of production to the substrate, may help in the animal's orientation. M. libycus marks low-lying objects in its environment by rubbing them with the abdominal pad, whereas, when objects are higher, the animal marks them with the gular area. The deposit of olfactory marks are frequently investigated by conspecifics. It appears that abdominal scent marking is closely associated with social status, agonistic relationships and territoriality. the latter notion is also associated with gular scent marking. The abdominal marking behavior as well as the size of the scent abdominal gland are sexually dimorphic in favor of the male. Chemical signals of preputial and clitorial glands may convey information such as sex and reproductive status. Male castration induces an extreme atrophy of the preputial and abdominal sebaceous glandular tissues, whereas this operation has no effect on the morphology of oral, gular, palmar and plantar glandular tissues. The preputial and abdominal gland changes induced by castration, are prevented by testosterone administration. these suggest that the preputial and abdominal gland integrities are androgen-dependent in the male.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

13. Metabolic rate, thermoregulation and distribution of greater long-tailed hamster (Cricetulus triton) in China

Creator:
Wang, De-Hua, Wang, Zu-Wang, Zima, Jan, Griffiths, Huw I., Burda, Hynek, and Sedláček, František
Type:
article and TEXT
Subject:
greater long-tailed hamster, Cricetulus triton, basal metabolic rate, BMR, thermoregulation, ecophysiology, and distribution
Language:
English
Description:
Metabolic rate, body temperature, and thermal conductance were determined in the greater long-tailed hamster (Cricetulus triton) at a temperature range of 5-36 °C. Oxygen consumption was measured by using a closed circuit respirometer. The thermal neutral zone was 39-34 °C. Within a temperature range of 5-31 °C hamsters could maintain a stable body temperature at a mean of 36.7±0.1 °C. Mean basal metabolic rate within thermal neutrality was 1.23±0.02 ml O2/g.h. Total thermal conductance was maintained within a temperature range of 5-15 °C (mean = 0.12±0.00 ml O2/g.h °C). The ecophysiological properties of the greater long-tailed hamster were: (1) a higher metabolic rate than predicted by the allometric scaling equation for eutherian mammals, but lower than that predicted for all rodents and slightly higher than predicted for cricetid rodents; (2) the body temperature was relatively low; (3) thermal conductance was relatively higher than predicted on the basis of body weight. All these characteristics are closely related to the species' life style (i.e. a burrowing, solitary, nocturnal species that feeds mainly on crop seeds and a small fraction of young crop shoots and insects). Greater long-tailed hamsters are primarily distributed in the northern Yangtse River area of China and cannot survive in extremely dr and alpine areas. We propose that the ecophysiological characteristics of the species might constrain its distribution and range extension into extreme deserts, high altitudes and cold areas.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

14. Metabolism in four rodent species from Ordox arid environment in Inner Mongolia, China

Creator:
Bao, Wei-Dong, Wang, De-Hua, Wang, Zu-Wang, Zima, Jan, Griffiths, Huw I., Burda, Hynek, and Sedláček, František
Type:
article and TEXT
Subject:
rodent, metabolic rate, adaptation, and Ordos Plateau
Language:
English
Description:
A comparative study of resting metabolic rate was conducted for the temperature range 10-37 °C for four rodent species, northern three-toed jerboa (Dipus sagitta) (body mass, Mb 79.2±6.8 g, n = 25), midday gerbil (Meriones meridianus) (Mb = 45.0±8.1 g, n = 10), desert hamster (Phodopus roborovskii) (Mb = 15.4±2.9 g, n = 26, and striped hamster (Cricetulus barabensis) (Mb = 24.8±4.0 g, n = 7) in the Ordos desert in summer (July), 1997. The minimum resting metabolic rates were 1.14±0.25 ml O2/g.h for three-toed jerboa, 1.35±0.3 ml O2/g.h for midday gerbil, 2.98±0.65 ml O2/g.h for desert hamster, and 2.75±0.37 ml O2/g.h for striped hamster. The thermal neutral zones (TNZ) were wide in the three desert species that was 26~37 °C in jerboa, 26~35 °C in gerbil, and 24~34 °C in desert hamster, respectively. For the non-desert species, striped hamster, it was 26~30 °C. The results do not confirm the hypothesis that desert rodents generally have lower metabolic levels than non-desert species. The high metabolic rates of these four rodent species were interpreted to be influenced by the stable availability of food resources and low environmental temperature in the Ordos Plateau. our results partly support the hypothesis that the metabolism characteristics are determined by food resources and environment temperature for animals living in arid regions.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

15. Muskrat (Ondatra zibethicus) demography and spatial structure in reservoirs in central Russia

Creator:
Gorshkov, Yurii A., Pudovkin, Andrey V., Zima, Jan, Griffiths, Huw I., Burda, Hynek, and Sedláček, František
Type:
article and TEXT
Subject:
muskrat, reservoirs, population structure, radioactive labelling, and age groups
Language:
English
Description:
We studied the demography and spatial structure of the muskrat population at the Nizhnekamsk Reservoir in central Russia. 45Ca radioactive prenatal labelling of muskrats was performed over a period of eight years. A total of 3,876 infividual muskrats were captured from a 12 km2 experimental plot and analysed on the basis of age, sex and presence of radioactivity. During the first year of life, the highest mortality was among muskrats from the latest litter, whilst during the second year of life it was amongst individuals from the earlier litters. Spring and autumn muskrat migration were studied and we observed a cyclical type of spatial structuring within the population. The proportion of individuals migrating in autumn varied from 18-57%, but significant differences in the migratory activities of different age groups were not observed. We found several tendencies throughout the eight years: a decrease in the proportion of the first litter (not overwintering), an increase in the proportion of third litters, and a decrease in the proportion of yearlings born in the first litter - we assume these represent responses to flooding.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

17. Nonshivering thermogenesis in four rodent species from Kubuqi desert, Inner Mongolia, China

Creator:
Bao, Wei-Dong, Wang, De-Hua, Wang, Zu-Wang, Zima, Jan, Griffiths, Huw I., Burda, Hynek, and Sedláček, František
Type:
article and TEXT
Subject:
nonshivering thermogenesis, rodent species, and Ordos Plateau
Language:
English
Description:
We examined the capacity for nonshivering thermogenesis in four rodent species residing in the Ordos Plateau of Inner Mongolia. Nonshivering thermogenesis (NST, maximum NST minus resting metabolic rate) was determined for northern three-toed jerboas (Dipus sagitta), midday gerbils (Meriones meridianus), desert hamsters (Phodopus roborovskii), and striped hamsters (Cricetulus barabensis) in spring (May), summer (July, and autumn (OCtober) captured in the Kubuqi desert in 1997. NST was induced by norepinephrine (NE) and measured by using the closed-circuit respirometer at 27 °C. Our results showed significant increases from summer to autumn in NST for the four species. NST capacities were 0.52±0.27 ml O2/g0.73.h (n = 7) in summer and 2.49±1.29 (n = 6) in autumn for jerboas, 1.61±0.74 (n = 6) in summer and 3.26±1.35 (n = 5) in autumn for gerbils, 3.62±0.75 (n = 5) in summer and 9.71±2.81 (n = 6) in autumn for desert hamsters, and 6.81±3.02 (n = 8) in summer and 11.23±2.77 (n = 8) in autumn for striped hamsters. These results suggest that small mammals living in the inland arid region on Ordos Plateau adapt to their extreme environment physiologically by adjusting their thermogenic capacities to cope with the dramatic seasonal temperature fluctuations.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

18. oestrus of female gerbils, Meriones unguiculatus, is indicated by locomotor activity and influenced by male presence

Creator:
Weinandy, René, Hofmann, Sylvia, Gattermann, Rolf, Zima, Jan, Griffiths, Huw I., Burda, Hynek, and Sedláček, František
Type:
article and TEXT
Subject:
locomotor activity, vasectomised males, oestrus cycle, and female aggression
Language:
English
Description:
Mongolian gerbils are territorial and live in family groups with established, stable male-female pairs. The objectives of this study were to investigate whether locomotor activity indicates female receptivity, and to evaluate the impact of a male on the stability of the female sexual cycle. To prevent gravidity, males were sterilised by vasectomy. Nevertheless, they behaved like intact males, displayed copulatory behaviour, and had normal mean serum testosterone levels of 1.1±0.2 ng/ml. Oestrus caused modulations in the activity pattern and hence influenced locomotor activity; female receptivity was reflected by an advance in the onset of activity. Male presence led to prolonged and irregular oestrus cycles in females. Three pairs were stable and nearly no attacks occurred for nine months. However, in four pairs, females suddenly attacked males. Males displayed flight and appeasement behaviours, but two died within 24 hours, and two were severely injured and had to be separated. Two of these females were paired again to other vasectomised males, but killed their cagemates after 3.5 and 12.5 weeks, respectively. In total, six of nine pairs were disrupted by female aggression, four males were killed and two males were separated but presumably would have otherwise died. Females presumably detected male infertility by repeated unsuccessful matings without sperm transmission and/or by physical impairments due to repeated pseudopregnancy. As a result they no longer invested in pair bonds that would eventually diminish their reproductive fitness.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

19. overview of Miocene rodents from Bełchatów (Poland)

Creator:
Garapich, Andrzej, Zima, Jan, Griffiths, Huw I., Burda, Hynek, and Sedláček, František
Type:
article and TEXT
Subject:
Neogene, fossil rodents, and biostratigraphy
Language:
English
Description:
More than one thousand rodent remains have been found in three different lacustrine sediment beds of Miocene age at Bełchatów (Poland) - an opencast brown coal mine. Three fossil assemblaged (Bełchatów C - the oldest, Bełchatów B and Bełchatów A) contain abundant rodent remains (mainly teeth) and correspond to biostratigraphic zone MN 4/5, MN 5/6 and MN 8/9, respectively. Aboud 80% of the rodent material was found in the uppermost layer (Bełchatów A). The remaining two assemblages, of not dissimilar ages and with similar Orleanian/ Astaracian faunas, countain 11% (Bełchatów B) and 9% (Bełchatów C) of the material studied. Most species (except for the relatively numerous Sciuridae and Castoridae and one dipodid tooth) have already been described. However, recent studies on cricetids and eomyids have led to a revision of the previously proposed ages of Bełchatów C and Bełchatów A.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

20. Poetential occurrence of the birch mouse (Silista betulina) in the Bohemian Forest (Šumava)

Creator:
Weiter, Libor, Heřman, Michal, Sedláček, František, Zemek, František, Zima, Jan, Griffiths, Huw I., and Burda, Hynek
Type:
article and TEXT
Subject:
Silista betulina, remote sensing and GIS, model of occurrence, and habitat preferences
Language:
English
Description:
Based on ecological parameters of 15 localities with birch mouse (Silista betulina) occurrence a model of its potential distribution in a part of the Bohemian Forest (Šumava) in Czech Republic was set up. The following habitat parameters were included into the model: land cover (six classes), proximity to next cover type (ten classes), proximity to a stream (five classes), altitude (seven classes), slope (seven classes), exposition (four classes). These parameters were derived from the Landsat 5 TM data and from digital elevation model using EASE/PACE software. All raster format data had a 30 m pixel size and all geographical information system layers were rectified into maps scale 1 " 25,000, Gauss-Krüger projection. For each of the six parameters two histograms were calculated. The first one displayed the frequency of a membership of a pixel to a class under a mask of the whole study area and the second histogram under a mask of the area of the birch mouse occurrence. The birch mouse preferred: the closest proximity to a stream (0-60m), flat terrain (slope < 5°), north-eastern and south-eastern expositions, the altitude between 700-900 m a. s. l., unmanaged meadows and pasture, boundaries between meadows and pastures or meadows and forests. The overall probability of the occurrence calculated according to these factors revealed areas of the most probable occurrence above all along the Vltava river system. This model was successfully verified by pitfall trap collection of birch mouse in three randomly chosen localities with the highest calculated probability of the occurrence.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/