Pipefish Sexual Selection

Lake Malawi’s cichlid male population of fish are tested on their ability to build bowers to attract the female population. Altering this extended phenotype, or ability to build bowers resulted in no change of mating, but males that built successful bowers showed to

Results showed that clutch temperatures were relatively stable throughout the day, and that certain temperatures were, indeed correlated with observed offspring sexes. Though this study tested the American crocodile, Crocodylus acutus, it provides evidence of a correlation between egg temperature and the resulting sex of offspring. Charruau also presented an important point about global warming possibly posing a threat to the ratio of female to male offspring being produced in the near future, due to the fact that alligator sexing is based solely on environmental temperatures. These disrupted ratios could ultimately lead to the extinction of certain species, which are dependent on this mode of sex

Sexual reproduction has caused monogamy in some species. In these species, it is essential for the father to help raise the young, but the father won’t help unless he believes that the

In the article, “How a Seahorse Dad is like a Pregnant Woman” by Sarah Zielinski, may sound comical, but much to my surprise, has some biological information that is worth reading. Unlike human, beings male seahorses carry the babies, instead of the women. A male seahorse carries the eggs of his mate in a pouch. Inside the male is where the eggs become fertile and start the growing process. The pouch, or the homes of the eggs are inside the male, around the stomach region. The male’s pouch is very adaptable. When the male is not pregnant the pouch is not sealed off, but when there are eggs in the pouch it becomes sealed, isolated from anything else. When eggs occupy the pouch it adapts its size and the nutrients it realizes according to the

Seahorse courtship may last from several minutes to days depending on the species of seahorse. In a wild population of H. whitei, the female seahorse traveled to her mate each morning and they interacted for 6-10 min, performing the first few movements of courtship (Vincent & Sadler, 1995). During this life stage the female's abdomen grew rounder as she prepared the eggs inside her, and the male prepared his brood pouch. He may inflate the pouch with water by opening the hole at the top of his pouch. Both seahorses were observed to point their snouts at the surface and brighten their colors many times. Eventually, both floated upward with their abdomens lined up. The female inserted her ovipositor, a tubular organ, into the male's brood pouch and deposited her eggs, where they were fertilized by male (Vincent, 1990). After courtship, both male and female seahorses exhibited visible evidence of having mated, as the female girth diminished and the male pouch filled (Vincent & Sadler,

The female seahorse makes the eggs. When the male and female mate, the female deposits her eggs inside of the seahorse's pouch. The eggs are fertilized by the male inside of his pouch. This pouch regulates water salinity, blood flow and temperature. The seahorse can deliver anywhere from five to 1,000 babies at one time. The seahorse species are one of the factors that affect how many babies the seahorse will deliver.

Deep down in the dark blue sea, male pregnancies are not extraordinary. Believe it or not female seahorses are actually the ones that impregnate the males. The reproductive process starts off by the male and female meeting up and “dancing”. One can think of this as being the first date. The two will continue to meet and swim together along with intertwining their tails several days before actually mating. The fish will also grip a strand of sea grass and whirl around it in unison. This kind of dancing and courtship synchronizes the movements of the seahorses and prepares the male to receive the eggs when the female is ready to deposit them (Maia, et al. 2013).

It is usually the case that the courts the female rather than the other way around because females needs to be more selective. This is due to generally females invest more than males, eggs are much larger than sperm, females are generally saddled with offspring and females are physiologically limited by fertility rates. So if the female uses filtering techniques she will attract the most suitable suiter to breed with ensuring her offspring survival.

Mating season usually occurs during the winter. During the breeding seasons, males of various stingrays use their “ampullae of lorenzini” to sense certain electrical signals given off by other female counterparts before potential copulation. When the female is found within site, the male courts the female until he is able to bite at her pectoral disc (pre-copulatory biting). In this process the male bites off the female’s pectoral fins and in process, replaces one of his two claspers into her valve or cloaca. The clasper then transfers the sperm into the female’s oviduct where the egg is fertilized until the birth of the babies. All female Stingrays are internal fertilizers and therefore undergo a process called ovoviviparity.

Bateman’s hypotheses of sexual selection has influenced scientist such as Trivers and Parker to believe that “males are indiscriminate and females are ‘choosy’ (Bateman, 1948)”. However, Bateman never proved these assumptions with his studies as he did not study the behavior in both male and female drosophila (Gowaty, 2016). Scientists fail to acknowledge that drosophila is a simple pest that makes studying them easy and because they are simple creatures they fail to show or express the complexity of sex and behaviors of the animal kingdom. Not all animals are the same.

Asymmetry in decapods has been a focus of an on and off interest as observed by Oppenheimer (1974) in McLaughlin, et al.,(2004) among carcinologist as decapod asymmetry has been a focus of importance for nearly a century (Przibram 1905; Emmel 1908), then interest plummeted and risen again. Asymmetry in abdomen shape between male and female crab have been observed among Ranina ranina as early as the instar 1 larval stage (Minagawa, 1993) rendering this character to be sexually dimorphic among these crabs. Posteriorly attached to the carapace, these structure provides adherence for eggs for ovigerous females. What makes the R. ranina abdomen unique among crab species is it attachment to the carapace. While in most crabs, abdomen are folded towards the ventral aspect of the crab, in R. ranina, it is partially extended away from the ventral aspect that it looks like a tail instead of as an abdomen. The abdomen also participates in the digging activity of the crab (Faulks, 2006). Asymmetry in pleopods was observed among paguroids as an offshoot of the type of shells they are inhabiting. Asymmetry in shapes are often associated with the frequent use of a particular character such as handedness or constant use (McLaughlin, et

Dietary and environmental factors play a key role in many aspects of life, whether human or animal. This paper will discuss the many dietary and environmental factors that affect the sexual selection as well as sexual dimorphism, specifically in lizards. Sexual selection is a type of natural selection where one sex does the choosing of mates for the other sex, and members of the same sex are rooted against each other to compete for mates. In order for a mate to attract a female with a high reproductive fitness, it is important to do a little showing off, and this is where sexual dimorphism comes in. Sexual dimorphism is the differences between two sexes of the same species. There are many ways in which lizards can exhibit sexual dimorphism,

In this experiment we studied the preference of colored foliage due to the activity around neon foliage and green foliage. Poecilia reticulate is a small benthopelagic non-migratory fish that can inhabit both fresh and brakish water. They are native to Brazil, Guyana, Venzuela and the Caribbean island and commonly use in genetics research. In an experiment by zoologist Professor Helen Rodd, biologist Dr. Kimberly Hughes, ecologist and biologist Gregory Grether, and biologist Colette Baril they studied the color preferences of Poecilia reticulate in mating. Their research resulted in the female P. reticulate mating with the larger males with bright orange colors which came to the conclusion that the female mates with the “best” companion for

It was found that the inter- and intrasite sex ratios (1.1M: 1F at Bassetts Mead and 1.33M: 1F at Hale Farm) were not statistically significant; this reveals that there is no dominance by one particular sex. However, it was observed that there were slightly more males than females caught (Fig. 3.2). Primary sex ratios in crustaceans are typically 1:1 reflecting stable chromosome-based sex determination mechanisms. However, both genetic and epigenetic factors (e.g. environment) are known to distort sex ratios in some species and aberrant sex ratios can be produced by interspecific or

As in other sexually reproducing anisogamous species, humans have sexually dimorphic traits of both morphological and behavioural kinds. Such traits are said to have evolved through sexual selection, the limiting force allowing individuals to out-reproduce others. At the level of gametes, we expect asymmetries in reproductive effort and in reproductive potential, which yields sexual dimorphism. According to Triversian Parental Investment Theory (PIT), the sex of a species who provides higher post-zygotic investment, typically the female, would be more selective in mates, such that the sex who invests less in a species, typically the male, would require traits seen as attractive in order to have selective advantage. Moreover, as females serve as the limiting resource for reproduction, PIT predicts that males are expected to have higher variance in reproductive success (RS) than females, so intrasexual selection would operate more strongly in males, whose aggressive competition for mate access would yield differences in fitness maximising strategies, whether through somatic or behavioural traits. Thus, sexual selection, is the primary explanation for sex differences within a Darwinian framework. Vocal characteristics in men and women are considered sexually dimorphic traits. Puts, Jones and DeBruine (2012) cited that women’s average voice pitch post-puberty is much higher than men’s, that men speak in a more monotone voice, and that men’s vocal tracts and vocal folds are