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A study of the sex ratio of newborn farmed american minks (Neovison vison) influenced by mating term and duration of pregnancy of females

100%

Felska-Blaszczyk L., Seremak B., Lawrow N.

Acta Scientiarum Polonorum. Zootechnica

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2020

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tom 19

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nr 1

2

Sex ratio in litters of domestic pigs [Sus scrofa f.domestica Linnaeus, 1758]

100%

Gorecki M. T.

Biological Letters

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2003

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tom 40

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nr 2

3

Influence of operational sex ratio and density on the copulatory behaviour and mating system of Brandt's vole Microtus brandti

100%

Zhang J., Zhang Z.

Acta Theriologica

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2003

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tom 48

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nr 3

The pattern of copulatory behaviour of Brandt's vole Microtus brandti (Radde, 1861) is similar to patterns 11 and 12 as described by Dewsbury and Dixson: no lock, single intromission, thrusting after intromission and multiple ejaculations. Under constant density, when the operational sex ratio (OSR, male to female) was skewed to the males, the mating opportunity of males decreased due to mating interference, while the mating input of female remained the same; when the OSR was skewed to the females, male voles tended to increase mating input while females did not. Under the same OSR (1:1), when density increased, the mating opportunity of both sexes dramatically decreased due to mating interference between same sex individuals; the thrusting frequency of males increased, probably due to compensation for the decreased mating opportunity. There was a considerable probability of the voles forming monogamous and polygynous mating relationships. Our results did not support the prediction that when OSR is skewed to male, the mating interval of males will shorten. We suggest that the most predominant mating system and mating interference should be taken into account when investigating an OSR effect. Our study suggested that the Brandt's vole is prone predominantly to monogamy and polygyny. However, due to limitation of observation in the laboratory, further work should be combined with studies in the field.

4

Sex ratio of herring and sprat from the Southern Baltic basins in 1980-2000

100%

Grygiel W., Wyszynski M.

Bulletin of the Sea Fisheries Institute

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2003

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nr 3

5

Sex ratio manipulation through embryo mortality in the water vole [Arvicola terrestris]: Consequences for fitness

100%

Nazarova G., Skorova S., Evsikov V.

Polish Ecological Studies

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1994

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tom 20

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nr 3-4

6

Effects of site conditions on sexual dimorphism and sex ratio in lowland populations of Aruncus sylvestris Kostel. (Rosaceae)

84%

Marciniuk J., Marciniuk P., Rymuza K.

Polish Journal of Ecology

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2010

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tom 58

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nr 2

Studies on sexual dimorphism in reference to vegetative features and on the sex ratio in different environmental conditions were carried out in lowland populations of dioecious species Aruncus sylvestris. It was shown that female individuals of Aruncus sylvestris produced higher flowering shoots, longer inflorescences, more leaves and longer and broader leaves than the male ones. All listed differences were statistically significant. In populations of Aruncus sylvestris growing in optimum ecological conditions (fertile and wet soil, half-light) the sex ratio M/F is close to 1:1. Changes of ecological conditions along the gradient of fertility, habitat moisture (estimated by the types of phytocoenoses) and intensity of solar radiation caused marked drift of sex structure towards the male domination. Light intensity was the crucial factor for the sex ratio in studied populations. Populations growing in half-light showed sex ratio M/F ≈ 1:1 irrespective of habitat. Those growing in shade and in full light showed significant shift to male dominance. The largest deviation from 1:1 sex ratio (M/F ≈ 1.0:0.2) was observed in extremely unfavorable habitat conditions (full sun irradiance, dry soil, strong competition from Elymus repens (L.) Gould). Obtained results demonstrated that female individuals of Aruncus sylvestris had markedly higher habitat requirements compared with the male ones.

7

Inbreeding and offspring sex ratio in the pygmy hippopotamus (Cheoropsis liberiensis) population kept in zoological gardens

84%

Graczyk M., Cwiertnia P., Borowska A., Barczak E., Szwaczkowski T.

Folia Biologica

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2015

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tom 63

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nr 1

8

Seed sexing revealed female bias in two Rumex species

84%

Kwolek B., Joachimiak A.

Acta Societatis Botanicorum Poloniae

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2011

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tom 80

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nr 2

Sex-ratio bias in seeds of dioecious Rumex species with sex chromosomes is an interesting and still unsettled issue. To resolve gender among seeds of R. acetosa and R. thyrsiflorus (two species with an XX/XY1Y2 sex chromosome system), this work applied a PCR-based method involving DNA markers located on Y chromosomes. Both species showed female-biased primary sex ratios, with female bias greater in R. acetosa than in R. thyrsiflorus. The observed predominance of female seeds is consistent with the view that the female biased sex ratios in Rumex are conditioned not only postzygotically but also prezygotically

9

Patterns of river lamprey size and sex ratio in the Baltic Sea basin

84%

Bartel R., Bradauskas B., Ikonen E., Mitans A., Borowski W., Garbacik-Wesołowska A., Witkowski A., Blachuta J., Morzuch J., Bernas R., Kapusta A.

Archives of Polish Fisheries

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2010

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tom 18

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nr 4

10

The distribution and population sex ratio of Cacopsylla myrtilli [W.Wagner, 1947] [Hemiptera: Psylloidea]

84%

Labina E. S., Nokkala S., Maryanska-Nadachowska A., Kuznetsova V. G.

Folia Biologica

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2009

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tom 57

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nr 3-4

157-163

11

Correlation between nutritional selectivity and migratory activity of Rhizopertha dominica F. [Coleoptera, Bostrichidae]

84%

Klys M.

Journal of Plant Protection Research

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2006

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tom 46

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nr 4

369-378

The subject of this study was the lesser grain borer Rhizopertha dominica F. The aim of the experiments was to verify the hypothesis suggesting that the course of simultaneous vertical migration and horizontal spread of the R. dominica population is determined by nutritional and habitat selectivity. The following products were used as nutrients in the experiments: wheat, oat flakes, pearl barley and semolina. It was found that the course of a migration process is connected with nutritional preferences determined mainly by a nutrient type and its granulation. At the initial stage of the study the highest emigration was noted in the oat flakes. After a time the highest migration was directed to as follows: wheat, oat flakes, pearl barley and semolina. Females showed a higher migratory activity.

12

Predicting the potential impacts of trophy hunting on population structure of Himalayan ibex (Capra sibirica) in Northern Pakistan

84%

Khan M. Z., Begum F., Riaz M., Khan B., Karim R., Karamat A., Safina A.

Polish Journal of Ecology

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2019

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tom 67

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nr 3

13

Male-biased sex of extra pair young in the socially monogamous Red-backed Shrike Lanius collurio

84%

Schwarzova L., Simek J., Coppack T., Tryjanowski P.

Acta Ornithologica

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2008

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tom 43

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nr 2

235-239

Females of many socially monogamous bird species engage in — or even actively seek — copulations outside their social pair bond. However, in socially monogamous birds with low breeding abundance, such as the Red-backed Shrike, extra-pair paternity (EPP) was thought to be an exceptional and random incident. Drawing on samples collected in an unusually dense Red-backed Shrike population in the Czech Republic, we show through DNA microsatellite typing that among 65 chicks from 15 nests, 10 individuals (26.5%) had been sired by males other than the nest-attending social mate. All 10 extra pair young were of male sex. In all cases, genetic fathers of extra pair young stemmed from neighbouring territories. Extra pair fathers had significantly longer tarsi than social mates, indicating that female choice was a function of age-class dependent male body size. Our findings support sex allocation theory, which suggests that promiscuous females mating with higher quality males should produce mostly sons.

14

ENSO affects sex ratio progeny in captive Iberian red deer despite a steady feeding regime

84%

Estevez J. A., Landete-Castillejos T., Garcia A. J., Gaspar-Lopez E., Ceacero F., Gallego L.

Acta Theriologica

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2011

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tom 56

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nr 4

Climate variability greatly affects animals through direct and indirect effects. Animals with slow reproductive adaptation to ecological changes such as large mammals are likely to have evolved mechanisms to anticipate early such impacts of climate variability on the environment. One of the adaptive mechanisms between reproductive costs and benefits in mammals affects parental investment through biases in sex ratio. Deer might be likely to show an early detection of climate variability because conception takes place in early autumn, but the main raising cost in deer concerns lactation, which takes place at the end of the following spring. The aim of this paper is to assess whether there is a relationship between global indices of climate variability such as El Niño-Southern Oscillation (ENSO) and sex ratio of a captive population of deer. Results showed that there was a negative correlation (r=−0.65) between sex ratio and ENSO indices between 1996 and 2008. El Niño enhances drier conditions during the summer in the Iberia Peninsula, which in turn favours a female bias. Results also suggest that the mechanism of early detection of climate variability exerts a strong effect on female reproductive physiology because the long-term stability of food resources in our setting has not markedly reduced it.

15

Emigration activity of the saw-toothed grain beetle Oryzaephilus surinamensis L. (Coleoptera: Silvanidae) in various environmental temperatures

84%

Klys M.

Journal of Plant Protection Research

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2012

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tom 52

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nr 4

The study pertained to the saw-toothed grain beetle Oryzaephilus surinamensis L., a dangerous pest of stored food products. The studies were carried out in the laboratory. Thermostats were set at a temperature of 31°C; an optimum temperature for this insect species, and in temperatures lowered to 28 and 22°C. The relative air humidity was kept at 60 ±5% relative humidity (RH). The main topic of the study was to examine the effect of lower temperatures in the environment, on the emigration activity of O. surinamensis. In these conditions, the population dynamics and the sex structure in O. surinamensis populations were also studied. The saw-toothed grain beetle was found to display very high emigration activity at 31 and 28°C. Lowering the temperature to 22°C caused a decrease in emigration activity and total inhibition of emigration activity until the 120th day of the experiment. A higher emigration levels among females rather than males, was also observed.

16

Sex ratio in goitered gazelles (Gazella subgutturosa Guldenstaedt, 1780)

84%

Blank D., Yang W.

Acta Theriologica

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2013

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tom 58

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nr 1

We studied the sex ratio of goitered gazelles in the naturally arid environment of Kazakhstan over a 6-year period. The main methods in our study were taking transect counts and focal observations. The sex ratio of adult goitered gazelles has demonstrated a female bias due to a much higher mortality of males of all ages, especially during years with unusually severe winters. This phenomenon is typical for many polygynous ungulates, as well as other gazelle species. Surprisingly, our data demonstrated monthly fluctuations in sex proportions, along with a bias shift from a female-dominant population during most of the year to a male-dominant population during spring. We discovered, though, that our data did not reflect any real changes in the sex ratio of the population but, instead, revealed the radical changes in behavior of pregnant females before giving birth—hiding from danger in thick shrubs or broken terrain rather than fleeing. As a result, we were not able to see many pregnant females in our spring samples (before birthing), and so received a male-biased population. During the rest of the year (after birthing), females returned to their usual behaviors of fleeing from danger that then gave us a female-biased sex ratio that reflected a more accurate status in sex proportions of the population. So, our results discovered seasonal sex difference in hiding behavior which led to a bias based on visibility.

17

Sex ratio in foal crops sired by purebred Arabian stallions in the years 1989-2010

84%

Sobczuk D.

Annales Universitatis Mariae Curie-Skłodowska. Sectio EE: Zootechnica

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2013

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tom 31

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nr 4

18

Social structure in synanthropic populations of a murid rodent Mastomys natalensis in Senegal

84%

Granjon L., Duplantier J. M.

Acta Theriologica

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1993

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tom 38

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nr 1

Synanthropic populations of Mastomys natalensis (A. Smith, 1834) were studied in southeastern Sénégal in order to evaluate some elements of their social structure. Analysis of trapping data consisting in single and multiple captures indicates that adult males were less likely to be involved in multiple captures than any other category of individuals. Sex-ratio in adults was significantly female-biased, and multiple captures involving 4 individuals or more (up to 13) were characterized by the small number of adult males involved (usually one per capture). Dyadic encounters between males revealed a higher rate of aggressive behaviours in M. natalensis than in its sibling species M. huberti. These observations suggest that these synanthropic populations are subdivided in polygynous units in which: (1) a part of males are evicted from the social group before their maturity and (2) adult males of different social units display aggressive behaviour towards each other.

19

Does egg sex ratio in urban Kestrels [Falco tinnunculus] differ from parity?

84%

Rejt L., Gryczynska-Siemiatkowska A., Rutkowski R., Malewska A.

Polish Journal of Ecology

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2005

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tom 53

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nr 4

Paper tests the hypothesis that urban kestrels (Falco tinnunculus) are sex biased connected with urbanization gradient (central zone vs suburbs), laying date and level of PCBcontamination. Blood samples of 158 nestlings were collected on FTA cards. Sex of nestlings was determined using a multiplex PCR technique. Egg sex ratio among kestrels in Warsaw (Poland) was 51% and did not differ significantly from parity (n = 34 nests). Among broods at the beginning and at the end of the breeding season proportion of males was significantly higher than in the middle of the season. Sex ratio was significantly different along the urbanization gradient. Proportion of males in broods at the central zone reached only 44% contrary to the external zone where males composed 65% of chicks. Possibly influence of laying date, female condition as well as population size and isolation is discussed. For assessing the level of PCBs small amount of blood (approximately 1 mm³) was collected from the brachial vein from 83 individuals (17 nests). All samples from a particular nest were pooled together to increase the possibility of successful analysis. Among most broods (pooled data for nests with complete and partial hatching) contamination of PCBs in nestlings’ blood was low (average level of PCBs was 55.1 ppm, range: 0–252.8). A trend toward decreasing proportion of males among broods with higher PCB-contamination was found to be insignificant. Probably level of organic contamination in chicks’ blood depends more on pollution existing in rural hunting areas and is not directly connected with nest site and its close vicinity.

20

Growth and reproductive biology of loaches Cobitis sp. in Lake Lucien, Poland

84%

Kostrzewa J., Przybylski M., Marszal L., Valladolid M.

Folia Biologica

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2003

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tom 51

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nr Suppl.

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