scholarly journals Biased sex-ratio in woodland grouse population of the Tatra National Park, suggested by molecular sexing of non-invasive samples

2021 ◽  
Vol 63 (2) ◽  
pp. 129-136
Author(s):  
Anna SANTOREK ◽  
◽  
Tomasz ZWIJACZ-KOZICA ◽  
Beata DULISZ ◽  
Dorota MERTA ◽  
...  
Keyword(s):  
Sex Ratio ◽  
National Park ◽  
Large Deviation ◽  
Survival Rates ◽  
Molecular Sexing ◽  
Black Grouse ◽  
In The Wild ◽  
Biased Sex Ratio ◽  
Tatra National Park ◽  
Genetic Assessment

Sex ratio (ratio between the number of male and female individuals in a population) is an important factor contributing to the survival rates of the population in wild. Imbalanced sex ratio is often the cause of diminished survival rates of endangered species. The analysis of DNA collected through noninvasive methodologies effectively allows to monitor populations of rare species or species that are difficult to observe in the wild. Such method was used to determine the sex ratio in populations of the capercaillie (Tetrao urogallus) and black grouse (Lyrurus tetrix) in the Tatra National Park. We collected over 250 samples (mostly excrement) in the area of the Tatra National Park and identified species via microsatellite genotyping and determined the sex using fragments of the CHD gene. We found that the majority of the samples belonged to male specimens irrespective of the species suggesting a large deviation from an equal sex ratio in wild populations of capercaillie and black grouse in the Tatra National Park. Our results point out the fundamental contribution of genetic assessment of sex ration to monitor the viability of both species in the Tatra National Park.

scholarly journals Noninvasive genetic census of greater one-horned rhinocerosRhinoceros unicornisin Gorumara National Park, India: a pilot study for population estimation

Oryx ◽  
2016 ◽  
Vol 50 (3) ◽  
pp. 489-494 ◽  
Author(s):  
Udayan Borthakur ◽  
Pranjal Kumar Das ◽  
Anjan Talukdar ◽  
Bibhab Kumar Talukdar
Keyword(s):  
Sex Ratio ◽  
National Park ◽  
West Bengal ◽  
Legal Protection ◽  
Population Estimation ◽  
Female Sex ◽  
Rhinoceros Unicornis ◽  
In The Wild ◽  
Genetic Techniques ◽  
Male To Female

AbstractThe greater one-horned rhinocerosRhinoceros unicornisis a flagship species for conservation in protected areas in India and Nepal. In India the species is afforded the highest level of legal protection under Schedule I of the Wildlife (Protection) Act 1972. Although censuses of greater one-horned rhinoceros have been carried out for decades using the traditional total count method, no advanced scientific approach has been adopted for population estimation of the species in India or elsewhere. We optimized noninvasive genetic techniques for identification of greater one-horned rhinoceros from dung samples, and applied these to estimate the number of rhinoceros in Gorumara National Park, in West Bengal, India. Our results confirmed the presence of 43 individuals from 60 dung samples collected throughout the Park in 2011. We confirmed a male-to-female sex ratio of 3.8 : 1, based on analysis of DNA from dung samples, using a y-chromosome linked marker. Our results are in concordance with a census carried out by the West Bengal Forest Department that found 42 rhinoceros in the Park, with a male-to-female sex ratio of 3.5 : 1. Our study thus demonstrates the feasibility of using a noninvasive genetic approach for population estimation of greater one-horned rhinoceros in the wild.

Population demography and sex ratio in a Neotropical damselfly (Odonata: Coenagrionidae) in Costa Rica

1989 ◽  
Vol 5 (2) ◽  
pp. 159-171 ◽  
Author(s):  
Linda D. Hamilton ◽  
Robert D. Montgomerie
Keyword(s):  
Costa Rica ◽  
Sex Ratio ◽  
Survival Rates ◽  
Small Population ◽  
Mature Adults ◽  
Egg Formation ◽  
Significant Difference ◽  
Biased Sex Ratio ◽  
Males And Females ◽  
Prereproductive Period

ABSTRACTThroughout the latter part of the dry season (January-April) of 1985 and 1986, we studied the demography of mature adults in a small population of Argia chelata along a stream at Monteverde, Costa Rica. Males defended sunlit spots along the stream between 1030 h and 1400 h central standard time each day and females visiting these sunlit spots were soon mated. By individually marking all mature adults in the population we found that there was no significant difference between the sexes in daily survival rates (0.85 for males and 0.86 for females). Lifetime mating success was positively correlated with longevitiy in both males and females but the ability of males to obtain a mate appeared to be independent of age.Although the sex ratio at emergence was 1:1, that of mature adults at the stream was strongly male-biased (87% male), perhaps as a result of a longer or more risky prereproductive period in females related to the costs of egg formation. We argue that the strongly male-biased sex ratio has important effects on the mating system of this species in that the male contact-guards the female for the entire oviposition period each day. Although this limits each male to mating with one female per day, it probably ensures that the male will fertilize most of the eggs laid by the female that day.

A male-biased sex-ratio in non-breeding Hooded Plovers on a salt-lake in Western Australia

2003 ◽  
Vol 9 (4) ◽  
pp. 273 ◽  
Author(s):  
M. A. Weston ◽  
F. J. L. Kraaijeveld-Smit ◽  
R. McIntosh ◽  
G. Sofronidis ◽  
M. A. Elgar
Keyword(s):  
Sex Ratio ◽  
Western Australia ◽  
Salt Lake ◽  
Breeding Population ◽  
Sex Bias ◽  
Molecular Sexing ◽  
Allopatric Populations ◽  
Wading Bird ◽  
Biased Sex Ratio ◽  
Threatening Processes

The Hooded Plover Thinornis rubricollis is a threatened, sexually monomorphic wading bird that occurs in two allopatric populations in eastern and western Australia. We used a PCR-based molecular sexing technique to sex captured birds from both populations. We found 69% of adults captured at a salt-lake in Western Australia were male. We tested for a sex-bias in our trapping technique by examining the sex-ratio of eastern birds captured under circumstances analogous to the western capture operation. No sex-bias in the trapping technique was apparent although the sample size was low. This suggests that the male-bias at the lake was real. Any spatial or habitat-related segregation of the sexes must be investigated before we can conclude that the bias is a trait of the western population. If the bias occurs in the population as a whole, then the effective size of the breeding population will be less than that indicated by counts. If the sexes segregate to different sites or habitats, then spatially constrained threatening processes may lead to a skewed sex-ratio.

THE ESSENTIAL CONTRIBUTION OF CAPTIVE SUMATRAN ELEPHANT IN ELEPHANT TRAINING CENTER, WAY KAMBAS NATIONAL PARK FOR WILDLIFE GENETICS CONSERVATION

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Elly Lestari Rustiati ◽  
Priyambodo Priyambodo ◽  
Yanti Yulianti ◽  
Eko Agus Srihanto ◽  
Dian Neli Pratiwi ◽  
...  
Keyword(s):  
National Park ◽  
In Situ Conservation ◽  
Training Center ◽  
Conservation Effort ◽  
In The Wild ◽  
Wildlife Genetics ◽  
Way Kambas National Park ◽  
Human Conflict ◽  
Essential Contribution

Way Kambas National Park (WKNP) is home of five protected big mammals including sumatran elephants.  It shares its border with 22 of 37 villages surrounding the national park.  Understanding their existence in the wild is a priority, and  wildlife genetics is a crucially needed. Besides poaching and habitat fragmentation, wildlife-human conflict is one big issue.  Elephant Training Center (ETC) in WKNP is built for semi in-situ conservation effort on captive sumatran elephants that mainly have conflict histories with local people.  Participative observation and bio-molecular analysis were conducted to learn the importance of captive Sumatran elephant for conservation effort.  Through captive sumatran elephants, database and applicable methods are expected to be developed supporting the conservation of their population in the wild.  Participative observation and molecular identification was carried on captive sumatran elephants in ETC, WKNP under multiple year Terapan grant of Ministry of Research and Technology Higher Education, Indonesia. Gene sequence and cytological analyses showed that the captive sumatran elephants are closely related and tend to be domesticated.  Translocation among ETC to avoid inbreeding, and maintaining the captive sumatran elephant as natural as possible are highly recommended. Developing genetic database can be a reference for both captive and wild sumatran elephants.

No room for males in caves: Female‐biased sex ratio in subterranean amphipods of the genus Niphargus

2021 ◽  
Author(s):  
Ester Premate ◽  
Špela Borko ◽  
Simona Kralj‐Fišer ◽  
Michael Jennions ◽  
Žiga Fišer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Biased Sex Ratio

Male-biased sex ratio in Argulus canadensis Wilson, 1916 (Crustacea: Branchiura) ectoparasitic on sticklebacks

1989 ◽  
Vol 67 (8) ◽  
pp. 2078-2080 ◽  
Author(s):  
Robert Poulin ◽  
Gerard J. FitzGerald
Keyword(s):  
Salt Marsh ◽  
Sex Ratio ◽  
Laboratory Experiments ◽  
Fish Predation ◽  
Reproductive Behaviour ◽  
Egg Deposition ◽  
Alternative Hypotheses ◽  
Biased Sex Ratio ◽  
The Difference ◽  
Fish Hosts

Females of the ectoparasitic crustacean Argulus canadensis must leave their fish hosts at least temporarily to deposit their eggs on the substrate. To test the hypothesis that this difference in reproductive behaviour between the two sexes could result in male-biased sex ratios on their stickleback hosts, we sampled sticklebacks in tide pools of a Quebec salt marsh from early July to early September 1986. During this period, fish harboured significantly more male than female A. canadensis. Laboratory experiments were done to test two alternative hypotheses offered to explain this biased sex ratio. The first hypothesis was that male A. canadensis were more successful than females in attacking their stickleback hosts; however, we found no differences in attack success on their hosts between the two parasite sexes. The second hypothesis was that sticklebacks ate more female than male A. canadensis. Although males were less vulnerable to fish predation than females, the difference was not significant. We conclude that sexual differences in reproductive behaviour, i.e., egg deposition behaviour of females, can account for the male-biased sex ratio of A. canadensis on sticklebacks.

Female-Biased Sex Ratio at Hatching in the Green Woodhoopoe

The Auk ◽  
1990 ◽  
Vol 107 (4) ◽  
pp. 765-771 ◽  
Author(s):  
J. David Ligon ◽  
Sandra H. Ligon
Keyword(s):  
Sex Ratio ◽  
Biased Sex Ratio

Variably male-biased sex ratio in a marine bird with females larger than males

Oecologia ◽  
1999 ◽  
Vol 118 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Roxana Torres ◽  
Hugh Drummond
Keyword(s):  
Sex Ratio ◽  
Marine Bird ◽  
Biased Sex Ratio

Effects of phytoseiid predators on the sex ratio of the spider mite Panonychus ulmi

1991 ◽  
Vol 69 (1) ◽  
pp. 208-212 ◽  
Author(s):  
Dan L. Johnson ◽  
Heather C. Proctor
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Spider Mite ◽  
Total Population ◽  
Panonychus Ulmi ◽  
Encounter Rate ◽  
Male Mortality ◽  
Adult Sex Ratio ◽  
Biased Sex Ratio ◽  
Male Activity

The effect of predator presence on the adult sex ratio of a spider mite (Panonychus ulmi) was examined in a field experiment. Phytoseiid predators (chiefly Typhlodromus occidentalis) were removed from 32 trees harboring P. ulmi populations, and allowed to remain at natural levels on 32 other trees. Both total population density and proportion of males in the prey population were significantly higher in predator-free trees. Mechanisms that could explain the increase in the proportion of males are examined. The most probable is that greater male activity results in a higher encounter rate between predator and prey, and that subsequent higher male mortality when predators are present exaggerates the female-biased sex ratio. The theoretical effects of sex-biased predation on diplo-diploid and haplo-diploid organisms are discussed.

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