C. A. Domesticus: A Case Study

In site one, where the Parahomo fracticranius was discovered, it can be assumed that the habitat for the species was an open grassland due to the fact that other fossils of animals that lived in the area were grazers. Since there were 14 remains of both male and female sexes, it can be assumed that the P. fracticranius lived in a large multi-male, multi-female system. Based on the lectures from class, it is known that for most cases, multi-male, multi-female environments result in polypoly mating (Atkisson Lecture: Primate mating systems and primate evo). Therefore, it can be assumed that the P. fracticranius not only engaged in polypoly mating, but they also had some sexual dimorphism and large testes. The evidence that supports the sexual dimorphism claim can be seen when the body size of the female and male are compared since the male’s body size is 41 kg larger than the female’s.

The Pharomachrus mocinno has evolved many behavioural and physical traits as a result of adaptation to the current environment and lifestyle it leads, however this proposal will focus on the unusual plume tail length of the male P. mocinno. This particular species habitat requires nests as high as 22 meters in rotting trees (Seigfried et al. 2010). Therefore, the function of the feathers would typically be assumed to enhance flight, as that would make sense as a useful function in this scenario due to the high elevation. Surprisingly, however, the long length of the plume tail actually decreases the speed of the male bird due to the drag force of air (Norberg 1995) and requires it to drop backward off the branches before being able to fly forward normally (LaBastille et al. 1972). With such issues with the long plume tails, would sexual selection really be in this traits’ favour? In a study done on the widowbird such was the case; males with longer plumes were mated the most (Andersson 1982). However, the widowbird is completely black (including its tail), while in the case of Pharomachrus mocinno it is a very colourful bird. Previous studies also have shown, that the bright reflective colours on the male’s bodies help in attracting females (LaBastille et al. 1972).

In insect species with indirect sperm transfer, sperm is packed in a spermatophore that is either externally attached to the female 's genital opening or introduced into her bursa copulatrix. Sperm transfer is not immediate in these species, and consequently mate guarding has been suggested to function as a mechanism of guarding sperm until it is released from the spermatophore into the female (i.e. spermatophore guarding). Spermatophore guarding is relatively common in insect species with external spermatophores (e.g. Orthoptera; Alcock 1994; Simmons 2001), but supposedly absent in species with internal spermatophores and rapid sperm release (Simmons 2001). This study focuses on two hypothesis associated with mate guarding a tactic of many species that adjust their reproductive behaviour according to the apparent risk of sperm competition. The phenomenon of mate guard to consider sperm competition levels and evolution of internal spermatophore guard is wide spread in insects and other animals. We analyse two hypothesis one the rival exclusion followed by the next spermatophore renewal hypothesis. Results showed that as rival was introduced to the arena of mating of the distinctive original male (guard) in many cases showed a strong aggressive behaviour regardless of whether successively avert the rival. In the second hypothesis certainly majority of the incidents showed an attempt of

Gaalema performed the experiment “Sexual Conditioning in the Dyeing Poison Dart Frog” to increase the rate of reproduction among these endangered frogs. 38 dart frogs including 19 males and 19 females were put into pairs and separated into three different groups (Gaalema 8). The three groups included a control group that received no conditioning, an experimental group that received an active control conditioning, and another experimental group that received experimental conditioning (Gaalema 8). In the experimental condition, a green LED light would flash for approximately 90 second intervals followed by a 120 second interval of interaction between the opposite sex paired frogs (Gaalema 9). The LED lights were used as a conditional stimulus and the presentation of the opposite sex frog was used as an unconditional stimulus (Gaalema 9).

Males were courting either species, but the females were the predictors to whether copulation occurred. A small amount of variance was shown regarding the females. It was seen that female Simulans were not very choosy with who they mated with, however, Mauritiana females were very choosy both with the intersexual copulation and intersexual copulation. The Mauritiana flies still mated with their own species more than that of the other species but in low amounts. Males will still try to copulate with either species trying to pass on their traits but the females are choosy and decide who it is that will win.

This result is not very clear, since the purpose of the outcome does not suggest whether the use of space is correlated with environmental factors shaping mating

When one male group doesn’t have the luxury of having females, they form or join a group of males similar to a bachelor’s group. In some of these species, the group of males attacks the one male group in order to take his throne and seize the females (Hoglund, J. 1995). Sometimes, the females may get tired of sharing the male with the other females in the group. Hoglund recorded (1995, pg. 76) “so they seek out males from all male groups to mate with during breeding season. Such influxes occur seasonally between blue monkeys (Rowell, 1988), Hanuman Langurs (Boories et al., 1999), ring-tailed lemurs (Sussman, 1992), and sifakas (Richard 1992).” A nonhuman

When examining the frequency and duration of the web vibrations being produced by Stenolemus bituberus and the prey, the researchers observed that the assassin bugs created web vibrations similar to the low-amplitude web movements generated by exhausted prey. Additionally, the researchers found that the assassin bugs never generated the distinctive vibration caused by prey landing on the web, nor did they create the high amplitude long duration web vibrations caused by the wing beats of struggling prey2. They also found that prey continuously generated high amplitude vibrations as they struggled in the web, while the leaf only generated one large wavelength from its initial impact2.The researchers also found that the spiders generally had no response to the leaf, and that the female spiders responded to the vibrations of the courting male by assuming a copulatory stance2. However, the courting male spiders generated a repeated web vibration not observed from the other forms web stimuli, suggesting a method by which female spiders discriminate courting male spiders from the other web

In this chapter, Orr and Zuk explains the importance of ornaments of males and the mechanism behind sexual selection. The questions that they seek to answer involve the fact that why are the males fighting during mating season, and the ones with the colorful ornaments. In both human and animal relationship, there are many similarities, such as the fact that the male fights for the female such as their masculinity or traits that females look for whether an animal or a human. Darwin in The Origin explained that sexual selection involves competition, but for mating instead of fighting for survival, in The Descent went on to explain the relevance of the traits like the peacock tails.

Many animals exhibit unique mating patterns and over time have evolved species specific traits to grab the attention of potential mates. Sexual Selection allows for individuals who possess certain qualities to produce more offspring than others, resulting in the evolution by means of natural selection of that trait and the diminishing of the traits of the weaker individuals. This allows for greater fitness of an individual which will in turn benefit the species as a whole. Male Fiddle crabs possess one large claw, which has been observed to be used as a weapon and as a signal of courtship (Callander et al. 2013). In their study, Callander and her team used a robotic male crab claw to determine whether female fiddler crabs had a preference

Males and females differ considerably in how much they each invest in order to make offspring and a result of this, they approach mating with different methods. Researchers and scientists learn and examine these varying mating systems to explain how males and females pair up. A mating system explains the techniques males and females use to pair up when selecting a mate. It is important to begin by reviewing and understanding the reproductive strategies among primates. The major types of mating systems found in primates are monogamy and polygamy. Monogamy is a practice of mating in which one male pairs with one female. Polygamy also known as bisexual, is a pattern of mating in which a male mates with more than one female and a female mates with more than one male (Wong , 2010). Polygamy is then clarified into polygyny and polyandry. Polygyny is when one male mates with multiple females. Polyandry is when one female mates with multiple males. Recognizing the diversity of mating systems will help in understanding the interactive relationship of sexual size dimorphism and behavior in primates.

The first few chapters discuss in depth both the general rules for mate selection and the differences in mate selection and varying preferences for male and female genders. As explained in the intro the author theorizes that the current behavior of humans in relation to mating behavior can be linked to our evolutionary past. He references Charles Darwin 's theory of evolution and his idea of natural selection, which is the the process through which organisms adapt to their environment and in doing so tend to

The males in most cases are the most active in courtship- they are in fact, the best provided with and are the more attractive of the two sexes in various ways. The attractions are flaunted in an elaborate manner in the presence of the females; and also only during the mating season. It also happens to be, that the individuals of one sex are capable of feeling a preference for a certain individual of the opposite sex according to Darwin. When the above happens, like in the case of the argus pheasant where the females are attracted to the exotic shading of the ball-and-socket ornaments and designs on the wing feathers of the male, it is interesting to notice that the males especially flaunt their great plumes only during the mating season and preferably in the presence of his female counterpart/counterparts. The great plumes which prevent the wings from being used for flight, thus, can be traced to the fact that they were given to the male as an ornament. Also, interesting is the fact that, the females would likely mate with that male argus pheasant who had the greatest plume because it charms them.

Mate choice is a product of mate preferences form in the environment of evolutionary adaptiveness (EEA). Sexual selection suggests that females prefer males who they can gain benefits from such as gifts. This is shown in male birds who make nests for females in order to mate with them and also in insects who give nuptial gifts.

It is generally well understood that mating in animals is dependent upon a number of ecological factors that determine if, when, and how many times an organism can mate. These factors include, but are not limited too: spatial separation of mates and resources, how long the specimen are sexually active/virile, does this species advocate parental care for their young, sex ratio and mate availability, and ultimately sexual selection. These factors will be discussed, broken down, and addressed in detail throughout the course of this paper.