User:Sfmabbott/sandbox

Article Evaluation: Animal Sexual Behaviour

Content

In the "Mating Systems" section of the article monogamy is discussed, however the context of monogamy strays slightly from the point of sexual behaviour when it is also mentioned in social and genetic contexts, which may be slightly distracting to the reader. Two of the headings, "Sexual Behaviour" and "Mating Behaviour", overlap significantly and therefore could be combined into one. The difference between the two is not made clear, or even mentioned. I also feel that male-male competition and mate choice should be discussed in the section concerning sexual/mating behaviour since it is mentioned in the lead section but not discussed in further detail at any other point in the article, despite being so relevant to the topic of animal sexual behaviour.

Tone

The tone of the article does not appear to be biased as many topics are presented on the topic of animal sexual behaviour which consider many potential views on the term "sexual behaviour" and what may constitute "sex" amongst animals. There is also a section discussing potential biases in the domain of animal sexual behaviour itself due to the preconceptions of a number of researchers surrounding this once taboo subject and what should be considered sexual behaviour amongst non-human species (e. i. sexual behaviour without the purpose of mating, sexual behaviour for pleasure or amongst members of the same sex).

Citations

This article appears to lack sufficient sources and citations. The first and third paragraph of the lead section do not contain any citations even though claims are made concerning animal sexual behaviour. While the citation links do work properly, it appears that not all sources contain information relevant to the topic at hand. The second source [2] in the article, cited at the end of the first sentence of the second paragraph, does not contain information shared in the sentence or any information relevant to the topic of the article. The source discusses Indian history whereas the article discusses animal sexual behaviour. Many claims are made, facts are stated and terms are defined throughout the article without any reference to a source that may support the statement.

Talk Page

This article is a part of two different WikiProjects; WikiProject Animals and WikiProject Sexology and Sexuality. The talk page for this article mentions several other topics that they believe should be included or expanded on in this article, such as the sexual behaviour of domestic animals and the mating behaviour of non-human primates. One user in particular questions whether stags fighting should be considered an example of sexual behaviour. From what we have discussed in class, this would be considered an example of male-male competition and very much an example of sexual behaviour. The primary concern discussed on this talk page is the lack of appropriate citations.

Add to an Article : Sexual Selection

The Role of Male-Male Competition in Sexual Selection

Male-male competition is when two males of the same species compete for the opportunity to mate with a female. Sexually dimorphic traits, size, sex ratio and the social situation may all play a role in the effects male-male competition has on the reproductive success of a male and the mate choice of a female.

Conditions that Influence Competition

Sex Ratio

Janapese medaka, Orzyas latipes.

There are multiple types of male-male competition that may occur in a population at different times depending on the conditions. Competition variation occurs based on the frequency of various mating behaviours present in the population. One factor that can influence the type of competition observed is the population density of males. When there is a high density of males present in the population, competition tends to be less aggressive and therefore sneak tactics and disruptions techniques are more often employed. These techniques often indicate a type of competition referred to as scramble competition. In Japanese medaka, Oryzias latipes, sneaking behaviours refer to when a male interrupts a mating pair during copulation by grasping on to either the male or the female and releasing their own sperm in the hopes of being the one to fertilize the female. Disruption is a technique which involves one male bumping the male that is copulating with the female away just before his sperm is released and the eggs are fertilized.

However, all techniques are not equally successful when in competition for reproductive success. Disruption results in a shorter copulation period and can therefore disrupt the fertilization of the eggs by the sperm, which frequently results in lower rates of fertilization and smaller clutch size.

Resource Value and Social Ranking

Another factor that can influence male-male competition is the value of the resource to competitors. Male-male competition can pose many risks to a male's fitness, such as high energy expenditure, physical injury, lower sperm quality and lost paternity. The risk of competition must therefore be worth the value of the resource. A male is more likely to engage in competition for a resource that improves their reproductive success if the resource value is higher. While male-male competition can occur in the presence or absence of a female, competition occurs more frequently in the presence of a female. The presence of a female directly increases the resource value of a territory or shelter and so the males are more likely to accept the risk of competition when a female is present. The smaller males of a species are also more likely to engage in competition with larger males in the presence of a female. Due to the higher level of risk for subordinate males, they tend to engage in competition less frequently than larger, more dominant males and therefore breed less frequently than dominant males. This is seen in many species, such as the Omei treefrog, Rhacophorus omeimontis, where larger males obtained more mating opportunities and successfully mated with larger mates.

Winner-Loser Effects

A third factor that can impact the success of a male in competition is winner-loser effects. Burrowing crickets, velarifictorous aspersus, compete for burrows to attract females using their large mandibles for fighting. Female burrowing crickets, are more likely to choose winner of a competition in the 2 hours after the fight. The presence winning male suppresses mating behaviours of the losing males because the winning male tends to produce more frequent and enhanced mating calls in this period of time.

Effect of Male-Male Competition on Female Fitness

Male-male competition can both positively and negatively affect female fitness. When there is a high density of males in a population and a large number of males attempting to mate with the female, she is more likely to resist mating attempts, resulting in lower fertilization rates. High levels of male-male competition can also result in a reduction in female investment in mating. Many forms of competition can also cause significant distress for the female negatively impacting her ability to reproduce. An increase in male-male competition can affect a females ability to select the best mates, and therefore decrease the likelihood of successful reproduction.

However, some techniques can improve the fitness of the female. Group mating can positively affect the fitness of a female in Japanese medaka due to an increase in genetic variation, a higher likelihood of paternal care and a higher likelihood of successful fertilization.

Examples

A leaf-footed cactus bug, Narnia femorata.

In Japanese medaka, females mate daily during mating season. Males compete for the opportunity to mate with the female by displaying themselves aggressively and chasing each other. To obtain the selection of the females, they court the females prior to copulation by performing a courting behaviour referred to as "quick circles".

In leaf-footed cactus bugs, Narnia femorata, males compete for territories where females can lay their eggs. Males compete more intensely for cacti territories with fruit to attract females. In this species, the males possess sexually dimorphic traits, such as their larger size and hind legs, which are used to gain the most advantage over competitors when females are present, but are not used in the absence of females.

Anuran (such as frogs) select habitats (pools) free of conspecifics in order to minimize male-male competition for both themselves and their offspring. Displays are used in attempt to keep competitors out of their territory and deter sneaking behaviours, while fighting is only used when necessary due to the high costs and risks associated with fighting.

Peer review from user sjh1917

Your article is really well written! It was organized in a way that flowed from one topic to the next, and the information constantly builds on what you have previously mentioned. For example the information about the density of males and its effect on female fitness is easier to understand as a result of you having introduced the topic in the beginning when describing differences in competition techniques. Your explanation of the different types of competition tactics was also really clear. Your arguments were all presented in a neutral tone, and no section is imbalanced in the amount of content it has compared to other paragraphs of similar importance. The beginning paragraph about the types of competition tactics and techniques has a little more content than the other sections, which is expected and useful since it provides a good foundation for the rest of the topics discussed later. There are some small grammatical errors, but those should be easy to fix with a full read through of the article. In your paragraph on the risks of male-male competition your sentences switch back and forth between related topics. To make the paragraph more cohesive, you could present all the information regarding resource value first and then follow it with the sentences about the presence of females on competition. I also really liked how you backed up the concepts throughout the article with the examples of how the medaka and cactus bugs behave. Your article is well referenced, but you rely more on the first two references more than you use the third. Is there any way to incorporate examples from your third reference into the article to make the information taken from each reference a little more balanced? Great job! Sjh1917 (talk) 15:44, 7 November 2018 (UTC)

Peer review from user Rseward13

Sfmabbott,

Overall I think your article is very well done. The fact that this is an article that you are adding to and not starting from scratch but you still have a lead that is clear, easy to understand and sets the scene for what is to be discussed in your contribution to the sexual selection Wikipedia article (such a broad topic!). I think you organized your ideas well throughout the article by dividing it up into types, risks, effects and examples. I was surprised that you only have 3 references throughout the article, but you refer to them consistently throughout and they all come from reliable scientific journals, so the criteria of having credible references is absolutely grand. You certainly maintain a neutral stance throughout the article by simply addressing the facts and citing them accordingly. One thing I noticed in the very beginning is you did not cite your initial defintion of male-male competition, and I realize this might simply be because you have a thorough understanding of the topic enough to not refer to a dictionary but as a Wikipedian without the knowledge of you being in a biology/psychology class, this lack of a reference might be cause for concern. In general I think it might be beneficial to expand your examples section, with maybe finding some more examples in the literature of animals across more taxa to introduce to your article. I agree with sjh1917 in that your third reference is not quite as heavily used as the first, so it might be good to expand more on the leaf-footed cactus bugs or other invertebrate examples of male-male competition. I think your article is very well written, unbiased, well cited and uses reliable sources, but perhaps just needs a been more fleshing out. The skeleton is present and is extremely well done, but it might be of value to find some more examples. Overall, a great read!