Alectrurus risora: Does female preference for good quality grassland affect male mating success?
Introduction
The Strange-tailed Tyrant (Alectrurus risora) is a species that is endemic to southern South America. Over the years the species has become globally vulnerable due to severe habitat loss. Over 90% of its habitat has been lost due to fires and human interference. This has caused populations to become concentrated in certain areas, particularly in the Iberá wetlands which is in the province of Corrientes in north-east Argentina (Di Giacomo et al. 2015)
In the wild females use the grass, Imperata brasiliensis, for nesting. A previous study has shown that when a plot of land has sustained a fire in the past breeding season, females avoid
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Conversely, an indirect relationship suggests that the trait decreases fitness.
If the null hypothesis is valid then there must be another factor at play that influences mating success. Therefore, it can be stated that female preference for tall Imperata brasiliensis plants has no effect on the male’s fitness. A male with poor quality territory will have the same mating and reproductive success as the male with better quality territory. Therefore, neither male possesses an advantage over the other.
If the female preference for tall grass does not affect male mating success, then perhaps the elongated, extravagant tail that males sport is what predominantly influences mating success. For example, if researchers noticed that the males with more mates had longer tails than the males with less mates, then the next step would be to conduct a study determining whether mating success is influenced by the length of a male’s tail. In some birds, such as the long-tailed widow bird (Euplectes progne), a male’s mating success is dependent on the length of the tail (Andersson and Andersson 1994).
Literature Cited
Andersson S, Andersson M. 1994. Tail ornamentation, size dimorphism and wing length in the genus Euplectes (Ploceinae). The Auk 111(1): 80 –
Wise, M. J., Abrahamson, W. G., & Cole, J. A. (2010).The role of nodding stems in the goldenrod–gall–fly interaction: A test of the “ducking” hypothesis. Manuscript submitted for publication, Available from American Journal of Botany. (0900227)Retrieved from http://www.amjbot.org/content/97/3/525.full
The Northern White-tailed deer have a polygynous mating system (fcps.edu, nd). Most white tails mate in their second year but it is possible for females to become sexually active after only seven months. The male species are polygamous but may develop an attachment to a doe for several days or weeks. The female species come into heat in November for only twenty-four hours. If the female is not mated she will have a second heat...
Alden, Peter, Rich Cech, and Gil Nelson. 1998. National Audubon Society Field Guide to Florida. New York: Knopf. 2. Brown, Larry W. 1997.
The female reproductive system in birds is reduced in most species to a left ovary and oviduct. This unilateral reduction of the female reproductive system is thought to bear two benefits: it reduces the female’s body and it prevent the potential problem of simultaneously carrying two large fragile eggs within the abdominal cavity. It also balances the body with the liver on the right side adjacent to the left ovary.
Soule, Michael E et al. “Ecological Effectiveness: Conservation Goals for Interactive Species.” Conservation Biology 17.5 (2003) : 1238-1250.
Females like to choose mates who have very bright colors as it is a sign of the male’s good health and vigor. The natural and sexual selection can affect populations in three ways: directional (environmental conditions change in a consistent direction; one extreme of phenotypes is favored), stabilizing (environmental conditions are relatively constant; intermediate phenotype is favored), and disruptive selection (environment has more than one type of useful resource; both extremes of phenotypes are favored). An example of directional selection is pesticide resistance since only the insects with a resistance are favored; an example of stabilizing selection is that the smallest lizards have a difficulty defending their territory whereas the largest lizards are most likely to be eaten by owls; an example of disruptive selection are the black-bellied seedcrackers since they either have a large beak (which they can use to eat had seeds), or a small beak (which allows them to eat soft seeds). Disruptive selection shows a balanced polymorphism, which is when two or more phenotypes are maintained in a
Some individuals have developed different traits to help them in the process of intra-sexual competition. The organisms with more distinctive traits have greater reproductive success. More genes of those traits are then ‘selected’ and are passed onto the offspring of the organisms. Throughout time variability in these traits becomes
Social groups of primates closely relate to sexual dimorphism, because how each of their communities interact with one another plays a large role in sexual selection. Sexual selection, as Darwin stated, is a key factor and cause in the morphological dimorphism between sexes of a species. Additionally, sexual selection comes from male competition, which directly correlates to primate’s social structures. For example, genus gorilla is a part of a polygynous mating system, which consists of one male and multiple female. This creates an environment where males must compete with one another to reproduce and create offspring. Due to this competition, males must prove to be strong and attract themselves to females to ensure reproductive success. These strong male traits are favored in sexual selection, because the females are highly particular about the male they mate with, so there become specific male traits that are most desirable. Therefore, in polygynous groups, sexual dimorphism is the greatest (Frayer, Wolpoff, 1985). In comparison, a monogamous primate such as genus hylobate or gibbons has a social structure that consists of a more nuclear based family. There is a lot less male competition because males do not mate with multiple females. Therefore, primates are less dimorphic in monogamous social structures (Frayer, Wolpoff,
In order to understand the present lifestyles relating to different approaches and tactics applied by humans in mate choice preferences, there is the need to refer to Darwin (1859, 1871) evolutionary perspectives. Darwin (1871) sexual selection is the driving force for males and females reproductive quest for their genes survival. These driving forces have been classified into two categories as intra-sexual and intersexual mate selection.Intersexual selection is male sexual selection process whereby males compete with other males and the females choose the strongest as their ideal partner. Intra-sexual selection occurs when the male species fight among themselves and the strongest gain access to females for
Mills, Scott L., Daniel F. Doak, and Michael E. Soule. "The Keystone-species Concept in Ecology and Conservation." BioScience 43.4 (1993): 219-25. Apr. 1993. Web. 30 Oct. 2011.
Eastman, J. (1997).14-Crow and Jay Family (Corvidae). Birds of forest, yard, and thicket. (pp. 127- 145). Mechanicsburg, Pa: Stackpole Books. Retrieved from: eBook Collection (EBSCOhost) [Accessed 3 March 2014]
“Saving Wild Places - Latin American and the Caribbean - Yasuni National Park, Ecuador” Wildlife Conservation Society. N.p., n.d. Web. 22 Oct. 2013.
In South America lies the largest and most wondrous rainforest in the world, the Amazon Rainforest. This 1.4 billion acre forest represents over half of the planets remaining rainforests, and comprises the largest and most bio-diverse tract of rainforest in the world. Ten percent of all known species on the planet are found in this rain forest, most of which have yet to be discovered. For the past century, the Amazon has been gradually decreasing in size due to agricultural expansion, ranching, infrastructure projects, energy exploration and illegal logging. At its current state, the Amazon is losing land equal to the size of the state of Delaware every year. The destruction of this forest releases 340 million tons of carbon per year according to the World Wildlife Foundation, or WWF, which in turn cause climate changes everywhere around the world. Undiscovered species can hold the key to curing a plethora of diseases, but if those species become extinct those keys are lost forever. If nothing is done to prevent this, the world’s treasure trove of bio-diversity will cease to exist, creating irreversible damage to not only the South American people but also the rest of the world.
Evolutionary framework for human mating is based on three elements. First, strategies for mating developed to solve specific problems in human evolutionary history. Second, people behave differently depending on the type of mating involved. There are two types of mating, short term and long term mating. Short term mating is defined as casual sex (i.e. one-night stands and brief affairs). Long term mating is seen as a committed relationship (i.e. dating, going steady, and marriage). Third, males and females developed different strategies due to the difference in problems they have had over the course of human evolution (Buss 241). This paper will examine those strategies specific to males.
According to recent studies, the saolas are categorized as critically endangered, with its population size estimated to the miniscule numbers from 70 up to 7...