What is the identity of this spider from India?

I came across this strange guy today at my classroom in Tamil Nadu, India. It is a spider which is not very much bigger than an ant but with an artistic body. He has 8 legs, but the two on the front are raised above his head, just like a crab does. Can anyone identify this little guy?

Anyone identify this little guy?

That is a Siler semiglaucus, which is a type of jumping spider. It has the nickname of "metallic jumper", and can be found all throughout India, Indonesia, Philippines, and Thailand.

He has 8 legs, but the two on the front is raised above his head, just like a crab does.

Here is a wonderful collection of more images, which also includes locations of discovery.

The Physics of Spider-Man's Webs

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Still image from The Amazing Spider-Man 2. Image: Marvel

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Perhaps the most distinguishing feature of Spider-Man is his ability to shoot webs. Now, let’s be clear. Spider-Man’s webs are a technology-based superpower. Forget what you saw in previous Spider-Man movies. His webs don’t just come out of special holes in his wrists. Those movies were wrong. No, Peter Parker developed these devices using his brain (or maybe he stole them).

The first thing to consider is the strength of these webs. There are several methods that could be used to estimate the web strength. Let me just consider a case from a previous movie that shows Spider-Man using his webs to catch a falling car. What kind of tension would the webs need so that they don’t break? Oh, just find the weight of a car? Nope. That’s not good enough. The webs not only support the car, but also slow the car down.

Let’s say that a falling car has a mass of 2,000 kg and for 1 second before being stopped. This means that I can use the momentum principle to find the momentum of the car in the downward direction.

Since the car starts from rest, the initial momentum is zero. Now, what about stopping the car? Once the web grabs onto the car, there will be two forces on the car: the downward gravitational force and the upward force from the web. Of course a web doesn’t instantaneously stop the car, it also takes some amount of time over which the web stretches. All materials stretch a little bit. For simplicity, I will assume a stopping time that is also 1 second long. The momentum principle looks the same as before except there are two forces on the car and the final momentum is zero.

This means that the web would have to have a tension of at least 39,200 Newtons.

Let’s use this value to make a comparison to other web-like options. The strength of a material can be describe by the ultimate tensile strength. This is the maximum tension per cross sectional area that the material can withstand before breaking and is measured in units of MPa (mega Pascals - or 10 6 Newtons/m 2 . In order to get a maximum tension, you need to know the cross sectional area of the wire since obviously thicker wires are stronger. Here comes the first wild estimate (ok, not the first). Let me approximate the web shot from Spider-Man as a cylindrical shape with a radius of 1 mm. If I replaced the web with real materials of the same size, this would be their maximum tension (based on the values from Wikipedia).

  • Steel cable: 6,503 Newtons
  • Nylon rope: 235 Newtons
  • Spider silk: 3,142 Newtons
  • Carbon nanotube rope: 1.98 x 10 5 Newtons

Based on these calculations, it looks like carbon nanotube rope is the only thing that would work. Well, the steel cable could work but it would have to be much thicker with a radius of 2.5 mm.

In the recent versions of Spider-Man, it seems that all the webbing “ammo” is contained in a small watch-sized wrist thing. In order to estimate the amount of webs, Spidey (he lets his close friends call him Spidey) can shoot, I need to first settle on the webs. I am going to go with carbon nanotube rope. According to Wikipedia, this could have a density of around 0.55 g/cm 3 which I assume is the density for the nanotubes in the form of a cable.

How much webbing would Spider-Man need for just one shot? It seems like he primarily uses the webs for swinging. If I were Spider-Man (and I’m not saying either way), I would aim for a height of about 5 to 10 stories high. Let’s say this requires a web length of about 20 meters. Using my initial estimate of a 1 mm radius web, this would be a super skinny and long cylinder. The volume of this cylinder would be:

This would put the total web volume for one use at 6.28 x 10 -5 m 3 . That might be a little difficult to visualize in terms of the size. How about a comparison to the volume of a standard pencil with a radius of 0.25 cm. If all of this webbing was put into a pencil, the pencil would be 3.2 m long. That’s a long pencil and remember, that’s for just one of his typical web shots.

Well, then how big of a container would he need to have a reasonable number of shots? Let’s say he wants 50 uses of the web for each hand. If I were Spider-Man, that’s what I would want. In that case, we can find the web volume estimation by a factor of 50. That gives a total volume (per hand) of 0.00314 m 3 .

What would this look like if it fit around a wrist? If I use my own wrist for a basis, then I find that it has a circumference of 16.5 cm. In my web container design, I will let the cartridge go back 10 cm along my arm. Now I can calculate the thickness of this container. Maybe a picture will help. Here is a look at my device looking down the arm.

Using the values from my estimates, I get a container radius of 9.6 cm or a height above the wrist of 7 cm. Here is what that would look like.

Yes. That looks a little awkward. But just imagine how large this thing would be the webs were something like nylon or steel cable instead of nanotube rope.

I already said that it seems like these webs should be able to reach at least a 10 story building (about 30 meters). What kind of launch speed would a web need to get this high? Let’s just start with the assumption that that the front of the web is just a particle and that air resistance is negligible. Yes, that is obviously not realistic but I will proceed anyway. As a bonus, isn’t it great that I can say “not realistic” when talking about Spider-Man? This is what makes the Internet so great.

If a web is launched straight up, there will be only one force on it - the gravitational force. This constant force will make the vertical velocity decrease as it rises. At the highest point, the web velocity will be zero m/s (assuming it just barely makes it to the top). This will give an average vertical velocity of:

Since the web is slowing down with an acceleration of -g, I can find the total time to get to the top of the building using the definition of the acceleration.

Now I can use the average velocity and this time interval to get an expression for the change in vertical position.

And there is your expression for the launch speed of the web. Sure, you could have just used one of the kinematic equations but what fun would that be? Using a the value for the change in height of 30 meters, the web launch speed would be 24.2 m/s (54 mph). That doesn’t seem too bad, does it? But wait. What about air resistance.

I’ll admit that calculating the air resistance in this case can be quite tricky. I could use the typical model for air resistance that say the force from air is proportional to the square of the speed:

Here ρ is the density of air at about 1.2 kg/m 3 and A is the cross sectional area of the web. The problem is with the value of C which is a coefficient that depends on the shape of the object. If a web is like a cylinder, a longer cylinder (as the web shoots out) has a different drag coefficient than a shorter web. This means that I will just have to guess at a value for C.

Here is the next problem. As the web rises, it goes slower. With a slower web there is also less air resistance. This means that there is a non-constant acceleration on this rising web. In cases like this, the only practical method for solving for the motion is to use a computer to create a numerical model. It’s not too difficult, but if you want the details check out this previous post.

For this simulation, I am going to assume carbon nanotube webs with a radius of 1 mm and a length of 2 meters in a cylindrical shape. The mass of this section of web can be found from the density of 0.55 g/cm 3 .

You can see from this plot that the web doesn’t quite go 30 meters high - but it’s pretty close. Ignoring air resistance isn’t such a bad assumption so that the web launch speed of 24 m/s seems legit.

What if Spidey wants to shoot his webs at a bad guy somewhere down the street? How far away horizontally could these webs go? I’ll spare you the math (but it’s here if you want it) and just give you the expression for the horizontal projectile motion distance when and object is fired on level ground at 45°.

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I was born with what doctors call a micropenis, a penis so small that it cannot really be used for sex. The doctors wanted to cut it off and give me hormones to live as a girl but my parents luckily refused. I can still enjoy the pleasures of sex but I have to please any of my female partners with something besides my genitals. I've had male partners who actually like my little guy, so a lot of the issues I had were in my head not in my pants. Once I accepted who I was, a bisexual man with a micropenis, I was much happier. I wish that growing up people had understood this concept of intersex better and I wouldn't have felt so screwed up for the first 40 years of life. anon165535 April 5, 2011

wow that's a very narrow view of intersexed people. I have been on hormones for 15 years and it was a decision I made for myself. As it turned out, after some surgery to remove cancerous organs, I have to be on HRT for the rest of my life.

To suggest intersexed people who happen to be queer or have had consensual surgical intervention are invalid is so outrageous I am lost for words.

Some intersexed conditions assure that some of us will develop certain cancers due to the orientation of internal organs. It's good that you can affirm yourself as a man in every sense, but for some of us its not that cut and dried and therefore for some, it would be life threatening to not be on HRT. --India anon127989 November 18, 2010

I don't know of anyone with a Disorder of Sex Development who prefers the imprecise term "Intersex" who does not take some form of hormone therapy to enhance male or female characteristics, and I know a great many "Intersex" people.

Intersex as a term is insulting to me, I am male through and though "balls to bones" as the saying goes. That I was born with a congenital disorder is irrelevant, I am male.

Who I am in my head is much more important than who I am according to someone else's definition or terminology.

People who call themselves "Intersex" and take hormones to enhance either sex and claim being

"Intersex" is a natural form of being are deluding themselves, burying their heads in the sand. Intersex only exists as a disease state, in my opinion.

Cultural Influences on Adolescent Development

J. Ng , G.C. Nagayama Hall , in Encyclopedia of Adolescence , 2011

Academic Success

In studies with African American and Latino/a American adolescents, high racial and ethnic identities have been associated with positive academic effects. African American and Latino/a American students who report a higher ethnic identity as assessed by connectedness, awareness of racism, and a strong belief that achievement is valued by their cultural group, achieve higher grade point averages in eighth and ninth grades. Ethnic identity affirmation has also been positively associated with teachers' reports of student grades, work habits, and cooperation behaviors. Strong ethnic identity has also been linked with self-esteem, which in turn is associated with higher grades. It appears that high ethnic/racial identities contribute to a sense of ability and achievement for ethnic minority students, which in turn, contributes to academic success. In fact, a study with African American adolescents found that ethnic identity, self-efficacy, and maternal support predict adolescents' orientation toward future academic achievements (e.g., thoughts, beliefs, dreams about their academic future). Indeed, when African American parents discuss discrimination and promote academic achievement as part of a strong cultural identity, their adolescent children are more likely to perform well at school.

Positive associations between ethnic identity and academic attitudes have also been found among Mexican American, Chinese American, and European American ninth graders. Scores on racial centrality and private regard are positively associated with

the belief that education is integral for their future success

the intrinsic value of school (i.e., attitudes toward schoolwork)

the belief that school is useful for one's present and future lives

the belief that one is valued and respected by the teachers and other adults at their school and

students' identification with their school.

Thus, a strong ethnic identity was associated with positive academic attitudes for all groups in the study, including European Americans.

However, strong ethnic identity may not be positively associated with academic achievement. One important factor appears to be the way in which racial or ethnic minorities perceive academic success. Several studies have found that when Mexican American adolescents tend to associate academic achievement with European American culture, a strong ethnic identity is not related to grade point average (GPA) or attitudes toward school. Likewise, African American adolescents who associate academic achievement with ‘acting White’ tend to be less motivated to do well in school and report lower GPAs. However, willingness to interact with other ethnic groups was positively correlated with attitudes toward school, education, and GPA, which suggest that willingness to interact with other ethnic groups may be a component of academic success for Mexican Americans. Interestingly, for African Americans, those who have high racial centrality, high private regard, and perceptions of low public regard for African Americans may be more likely than others to go to college. In contrast, those who report low connectedness to their ethnic group, idealized perceptions of their ethnic group, or alienation from their racial group are less likely to continue to college. Youth who have a strong racial identity and report feeling low public regard for their racial group persisted in school because they had strong connections to their racial group and had realistic perceptions of how society regards African Americans. In contrast, youth with low connected identities lacked social support for persisting in school. Idealized youth were likely to face disappointment when they faced the reality of low public regard for African Americans. Alienated youth had negative regard for African Americans and perceived the public's regard similarly, which may have interfered with persistence in school.

Perceived discrimination can also impact African American adolescents' attitudes about academic achievement. A longitudinal study found that experiencing perceived daily discrimination in the school by teachers and peers negatively affected African American youth satisfaction with their schoolwork. The study also found that these perceptions of daily discrimination were associated with lowered self-esteem and increased their frustration and distress. Additionally, perceived discrimination predicted decreased importance and value of school, decreased sense of ability to do well in school, and declines in GPA. However, a strong ethnic identity attenuated these negative effects. A strong ethnic identity was found to promote school achievement and motivation and protected African American youth against the negative effects of discrimination. Interestingly, anticipated future discrimination was also associated with more academic motivation.

Another construct closely related to discrimination, racial stereotype, has also been found to influence short-term academic achievement and these effects can be positive or negative based on the type of racial stereotype being primed. Research with young adults has found that African Americans, Latino/a Americans, and Asian Americans can be adversely affected if the stereotype primes negative associations with academic or intellectual abilities. For instance, African Americans perform poorly on cognitive tests when they see a peer of the same race perform poorly. Similarly, research with Asian American females found that priming about ethnic identity produced better math performance compared to women who were primed about their gender identity or received no prime because the stereotype regarding Asian Americans is that they are good at math. In fact, priming about gender (i.e., exposing Asian American women to cues reminding them to think of their gender) resulted in poorer math performance. Although most research has concentrated on college performance, evidence suggests that stereotype threat begins to affect youth beginning at age 11 or 12, a critical developmental period for academic success. Interventions in decreasing stereotype threat by increasing beliefs and cognitions about students' ability to learn and the malleability of intelligence have been successful in increasing math and reading test scores for African American and Latino adolescents.

Navigating Multiple Identities: Race, Gender, Culture, Nationality, and Roles

In our increasingly complex globalized world, many people carry distinct, often conflicting, psychosocial identities. People live at the edges of more than one communal affiliation, bridging loyalties and identifications. This book is designed to explore how people attain or maintain personal integration in the face of often-shifting experiences of personal or social location—how people navigate the complexity of their multiple identities. One of the key premises of this book is that identity is rooted in social location and therefore always reflects the social and historical period in which i . More

In our increasingly complex globalized world, many people carry distinct, often conflicting, psychosocial identities. People live at the edges of more than one communal affiliation, bridging loyalties and identifications. This book is designed to explore how people attain or maintain personal integration in the face of often-shifting experiences of personal or social location—how people navigate the complexity of their multiple identities. One of the key premises of this book is that identity is rooted in social location and therefore always reflects the social and historical period in which it is formed and evolves. People are often fixed from outside themselves with labels that they must include or resist in their identity definition. Thus, even in our highly individualized society, identity remains socially constructed and people are not free to simple declare the meanings of their identity and have them accepted by others. Identities are fluid and context-dependent, and identity elements exist in readiness to be expressed depending on the external social factors that invite their emergence. The book considers individuals who are navigating across: • Racial minority or majority status • Cultures with different values • Gender identities • Roles • Cultural expectations versus individual definitions. The first section of the book attempts to look at identity theoretically and phenomenologically and assesses how current theory can aid in understanding the experience of multiple identity. The second and third sections of the book look at the identity navigation process in the United States and in cross-cultural populations.


Stan's synopsis for the Green Goblin had a movie crew, on location, finding an Egyptian-like sarcophagus. Inside was an ancient, mythological demon, the Green Goblin. He naturally came to life. On my own, I changed Stan's mythological demon into a human villain. [3]

The Green Goblin debuted in The Amazing Spider-Man #14. [4] At this time his identity was unknown, but he proved popular and reappeared in later issues, which made a point of his secret identity. According to both Stan Lee and John Romita, Sr., who replaced Ditko as the title's artist, Lee always wanted the Green Goblin to be someone Peter Parker knew, while Ditko wanted his civilian identity to be someone who hadn't yet been introduced. [5] [6] [7] Lee elaborated:

Steve wanted him to turn out to be just some character that we had never seen before. Because, he said, in real life, very often a villain turns out to be somebody that you never knew. And I felt that that would be wrong. I felt, in a sense, it would be like cheating the reader. . if it's somebody you didn't know and had never seen, then what was the point of following all the clues? I think that frustrates the reader. [7]

However, Lee prefaced this statement by admitting that, due to his self-professed poor memory, he may have been confusing the Green Goblin with a different character. [a] [7] Moreover, in an earlier essay he had said that he could not remember whether Norman Osborn being the Green Goblin was his idea or Ditko's. [8] Ditko has maintained that it was his idea, even claiming that he had decided on it before the first Green Goblin story was finished, and that a character he drew in the background of a single panel of Amazing Spider-Man #23 was meant to be Norman Osborn (who is not introduced until issue #37). [3] [9]

Ditko left the series with issue #38, just one issue after Norman Osborn was introduced as the father of Harry Osborn. The first issue without Ditko saw the Green Goblin unmasked. John Romita, Sr., who replaced Ditko as the title's artist, recalled:

Stan wouldn't have been able to stand it if Ditko did the story and didn't reveal that the Green Goblin was Norman Osborn. I didn't know there was any doubt about Osborn being the Goblin. I didn't know that Ditko had just been setting Osborn up as a straw dog. I just accepted the fact that it was going to be Norman Osborn when we plotted it. I had been following the last couple of issues and didn't think there was really much mystery about it. Looking back, I doubt the Goblin's identity would have been revealed in Amazing #39 if Ditko had stayed on. [10]

In the landmark story, "The Night Gwen Stacy Died" (The Amazing Spider-Man #121–122), the Green Goblin kills Gwen Stacy and later perishes in a fight against Spider-Man. However, the story's writer, Gerry Conway, had Harry Osborn adopt the Green Goblin identity in that story's aftermath, later remarking that "I never had any intention of getting rid of the Green Goblin as a concept". [11] Harry Osborn's becoming the Green Goblin was mostly well-received, with fans remarking that Harry was more menacing than his father had ever been. [12]

Several other characters would take on the Green Goblin identity, and writer Roger Stern later introduced the Hobgoblin to replace the Green Goblin as Spider-Man's archenemy. [13] In addition, a retcon during the "Clone Saga" determined that the original Green Goblin survived the events of The Amazing Spider-Man #122 and had been playing a behind-the-scenes role in Spider-Man's adventures since then.

Norman Osborn Edit

Norman Osborn is the first and most-known character connected with the Green Goblin alias who developed the equipment used by the others ever since he was exposed to the Goblin formula.

Harry Osborn Edit

Harold "Harry" Osborn is Norman Osborn's son and the second character who used the Green Goblin alias.

Bart Hamilton Edit

Dr. Barton "Bart" Hamilton was a psychologist born in Scarsdale, New York and the third character to use the Green Goblin alias. When Harry was put under medical care, Dr. Hamilton managed to make Harry bury the vendetta as the Goblin identity from Harry's subconscious via hypnosis. [14] Dr. Hamilton uses these secrets to be the third Goblin. [15] But since Harry has no knowledge of where Norman's strength-enhancing Goblin formula is, Hamilton is unable to locate it. He hatches an elaborate plot to kill Silvermane but Harry resumes the Goblin identity to stop him. They battle and Hamilton is accidentally killed by a bomb with which he meant to kill Spider-Man. [16]

Years later, there was speculation that Hamilton was the Hobgoblin but this is disproved. [17]

A Goblin that was presumably Hamilton appears as a member of the second incarnation of the Legion of the Unliving created by the Grandmaster. After being pitted against the Avengers, the group and their master are vanquished by Death. [18]

During the Dead No More: The Clone Conspiracy storyline, Bart's Goblin form is cloned by the Jackal's company New U Technologies. [19]

Phil Urich Edit

Philip Benjamin "Phil" Urich is nephew of Ben Urich and the fourth character to use the Green Goblin alias.

Nameless construct Edit

Norman begins trying to convince the public after returning from the dead of never being the infamous supervillain, and conspired with associate Doctor Angst genetically engineer a new Green Goblin, one slavishly devoted to help his case. [20] Norman uses this Goblin as a bodyguard, [21] to torment Spider-Man, [22] and in ploys designed to draw public sympathy (such as kidnapping Normie Osborn for ransom). [23] After Norman is incapacitated by the Gathering of Five, the Goblin is left alone and begins to degenerate due to no longer having access to the Goblin Formula required to keep him stable. The Goblin goes after Liz Allan in a desperate bid to find a cure for his condition, but is driven off by Spider-Man. [24] During a second attempt to capture Liz, the Goblin unmasks himself in front of Spider-Man (shuffling through a variety of faces (with the most prominent being Harry Osborn) after doing so) and melts into a pile of protoplasm as he claims Norman would return. [20]

In his first appearances, the Green Goblin seems to be a normal man (albeit very nimble and athletic) who gets his powers from his many gadgets. In later appearances, it is established that due to the "Goblin Formula", Norman and most successors to the Green Goblin persona possesses superhuman strength (lifting nine tons under optimal conditions), increased speed, reflexes, endurance, intelligence and healing rate, while Norman started with a portion of the chemical's power because of an accidental splash in the face during the time where one had to bathe in it long enough to get the full effect before the drinking version was created. Though much slower than the likes of Wolverine, he can regenerate damaged tissue and organs. However, if seriously wounded, it would leave scars on his body. His intelligence has been enhanced to gifted levels, though at the price of his sanity. His involvement with the Gathering of the Five loosened his grip on reality, though he is able to maintain some semblance of his sanity via chemically treated dermal patches. When not impaired by mental illness, Osborn is a cunning businessman, masterful strategist, and highly skilled in electronics, mechanics, engineering and chemistry. The Green Goblin is armed with a variety of bizarre devices. He travels on his bat-shaped "Goblin Glider", an incredibly fast and maneuverable rocket glider equipped with various armaments. Other weapons the Goblin uses include incendiary Pumpkin Bombs and Ghost Bombs, smoke- and gas-emitting grenades resembling jack-'o'-lanterns and ghosts, respectively, razor-edged boomerang-like throwing weapons called razor bats and gloves woven with micro-circuited filaments which channel pulsed discharges of electricity at nearly 10,000 volts. He wears a green costume underneath bulletproof chainmail with an overlapping purple tunic. His mask has a built-in gas filter to keep him safe from his own gasses.

Goblin Glider Edit

In the Green Goblin's first appearance in The Amazing Spider-Man #14, he rides a steel rocket-powered wingless broomstick (not a glider). In his second appearance in The Amazing Spider-Man #17, he changes to the familiar bat-shaped glider. The Goblin Glider's controls and microprocessor are located behind the head of the glider. The pilot is attached to the glider via electromagnetic clasps on the wings of the glider. It has great maneuverability and is steered mostly by leaning, but manual controls are available behind the head of the glider. The Goblin later added radio-linked voice controls to his mask. Its top speed is 90 miles per hour (140 km/h), and it can support about 400 lb (180 kg), though it could lift far more for brief periods. Flying at top speed with a full load and a full fuel tank would deplete its fuel supply in about an hour.

In the Goblin's later appearances, the glider possesses a wide array of armaments, including heat-seeking and smart missiles, machine guns, extending blades, a flamethrower and a Pumpkin Bomb dispenser/launcher.

Pumpkin Bombs, Ghost Bombs, and the "Bag of Tricks" Edit

A grenade used by the Green Goblin, the Pumpkin Bomb resembles a miniature Jack-o'-lantern and, when thrown, ignites almost soundlessly and produces enough heat to melt through a 3-inch (76 mm) thick sheet of steel. The Goblin carries these and a variety of other weapons, such as razor bats (akin to bladed boomerangs) and miniature "Ghost Bombs", in an over-the-shoulder satchel he calls his "Bag of Tricks". The Green Goblin has a range of other "Pumpkin Bombs" and "Ghost Bombs" at his disposal, including smoke-and gas-emitting bombs. Some release hallucinogenic gases, while others emit a specially-created mixture that neutralizes Spider-Man's spider-sense for a limited period of time. Still others emit a flame-retarding gas, which the Goblin once used against the Human Torch. [25] All of these are covered in a light plastic coating.

Goblinettes Edit

Some time after Norman's death, Harry is abducted by a trio of mysterious female Goblins. With the aid of Ben Urich and Molten Man, Spider-Man discovers that these "Goblinettes" are robots created by Harry, and controlled by a supercomputer containing copies of Harry and Norman's minds. The Goblinettes are destroyed along with the computer, which had been programmed to expose Normie Osborn to the same version of Goblin serum that killed Harry, in attempt to create a new Green Goblin. [26]

Order of the Goblin Edit

An offshoot of the Scriers cult founded by Norman, consisting of only his most loyal followers.

Goblin Gangs Edit

Following Norman's rise and fall from power, a number of Goblin Gangs sprang up across America. Composed mostly of white supremacists who agreed with his plans to remove the Asgardians from the country, they wear purple clothes, green face makeup and have goblin-based tattoos. [27] Vin Gonzales was revealed to have received one of these tattoos while in prison passing a message from Norman to Harry about Stanley Osborn. [28]

Goblin Nation Edit

The Goblin Nation, also known as the Goblin Underground, is a group of organized crime composed of Goblin-themed villains led by the Goblin King against the Superior Spider-Man. [29]

War Goblins Edit

In the eight-month ellipsis that occurred subsequent to the events of Secret Wars, a heavily bandaged arms dealer claiming to be Norman Osborn began selling Goblin-based costumes and equipment on the black market, establishing private armies of "War Goblins". [30]

As a fictional character, the Green Goblin has appeared in a number of media, from comic books to films and television series. Each version of the character is typically established within its own continuity within parallel universes, to the point where distinct differences in the portrayal of the character can be identified. Various versions of the Goblin are depicted in works such as Marvel's Ultimate line and Earth X.

2099 Edit

In the Marvel 2099 setting, the Goblin is a radical trickster who wants to prove that Spider-Man (Miguel O'Hara) is in the pay of a megacorp like Alchemax. He has bat-like glider-wings and a bag of "tricks", similar to the 20th century version. He also has the ability to project illusions. [31]

He is eventually unmasked, and appears to be Spider-Man's brother Gabriel O'Hara, although it is later revealed, in a retcon, that he is a shapeshifter who took Gabriel's identity. Writer Peter David, who quit the book between creating the character and the unmasking, has said that it was his intent for the Goblin to be female Catholic priest named Father Jennifer, and for Gabriel to be a red herring. [32] [33] This Goblin was never called the Green Goblin, but instead simply Goblin 2099. [31]

In All-New, All-Different Marvel, during a travel to 2099, Spider-Man (O'Hara) is captured by that era's Venom and Doctor Octopus. Miguel later wakes up in Alchemax, which is run by that era's Sinister Six. The Sinister Six discover that the Goblin is actually Father Jennifer D'Angelo, an undercover ally of Kasey. After receiving a message from the Sinister Six, Miguel and Kasey go to Alchemax to rescue Father Jennifer. Upon escaping, Spider-Man and Father Jennifer arrive at an area where the time door appears, but Jennifer is killed by Doctor Octopus.

In other media Edit

  • The Green Goblin 2099 is a playable character and a boss in Lego Marvel Super Heroes 2. [34] He first appears in Manhattan, after it has been made part of Chronopolis, and fights Spider-Man and Spider-Gwen alongside the Vulture, but both villains are swiftly defeated. Later, the Goblin 2099 obtains a shard of the Nexus of All Realities, which he uses to fuse Venom and Carnage into a new creature, dubbed "Carnom," whom he controls. When Spider-Man, Ms. Marvel, She-Hulk, Spider-Gwen, and Spider-Man 2099 arrive in Nueva York (also part of Chronopolis) and break into Alchemax to retrieve the shard, the Goblin 2099 unleashes Carnom upon them, but they defeat him and free him from the Goblin's control. The Goblin 2099 is last seen being pursued by Carnom in retaliaton for his abuse.

Avataars: Covenant of the Shield Edit

In the miniseries Avataars: Covenant of the Shield, which takes place in an alternative universe referred to as Eurth created by the Shaper of Worlds, the Green Goblin appears as the Goblin King. A small, nimble creature green in color and adorned in purple rags, the Goblin King is shown to speak solely in rhyme and runs a toll booth in the Webwood, extorting goods from travelers along with his henchmen the Six Most Sinister. [35]

House of M Edit

In the Spider-Man: House of M from the 2005 Marvel comics series House of M, there are two versions of the Green Goblin.

  • The first is Peter's wrestling friend and rival Crusher Hogan, who uses the identity as his wrestling franchise.
  • The second is Peter Parker himself, who, feeling guilty posing as a mutant when really he was a human given powers in the usual Spider-Man fashion (radioactive spider bite), poses as the Green Goblin to reveal the information about him being a human to J. Jonah Jameson, his then publicist, and eventually the entire world. Norman Osborn is also present in this continuity, as an industrialist whose company is bought out by Peter. [36]

MC2 Edit

Fury the Goblin Queen Edit

Élan DeJunae, daughter of the San Mardeo DeJunae crime family in South America, is betrothed to Normie Osborn when she is just a baby because of her father's involvement with the Order of the Goblin. [ volume & issue needed ]

From then on, Élan learns the family business and eventually makes connections with the Black Tarantula. She grows up training to follow Norman Osborn's footsteps, and eventually becomes the leader of the Order of the Goblin. Following a near fatal attack on Normie, Élan returns to New York to follow through with their arranged marriage, but Normie was not aware of the betrothal. Meanwhile, Élan and the Black Tarantula plot to use Spider-Girl to destroy Lady Octopus and Canis so they can take control of the New York underworld. Following plans made by Norman Osborn before his death, the Queen of the Goblins tries to dose Normie Osborn with a new version of the Goblin Formula. Spider-Girl manages to defeat Élan, but in the battle, the formula explodes and the Queen escapes. [ volume & issue needed ]

Because Normie spurned her and denied his place in the Goblin legacy, Fury crashes his wedding to Brenda Drago and forcibly bonds the Venom-symbiote to him in an attempt to corrupt him. This backfires, as Normie gained control of the symbiote and went on to become a hero. After Fury crashed Normie's wedding, Phil Urich (the good Green Goblin) defeats her and sends her to prison. [ volume & issue needed ]

Normie Osborn Edit

Normie Osborn is the son of Harry Osborn and Liz Allan, and the grandson of Norman Osborn. In the alternative timeline of the MC2 universe he becomes the Green Goblin and battles Spider-Man's daughter, May "Mayday" Parker, before reforming and becoming her ally. [ volume & issue needed ]

Phil Urich Edit

In the MC2 timeline, Phil Urich marries his girlfriend Meredith and is a forensic scientist and friends with Peter Parker. He is aware of both Peter and Spider-Girl's identities. Phil Urich resumes the Goblin identity, first under the name of the Golden Goblin, then as the Green Goblin with the assistance of Normie Osborn (III). After Phil lost a long series of battles, Normie recreates Phil's original mask, which grants him superhuman strength and other abilities, greatly enhancing his effectiveness. He is also a founding member of the New New Warriors. [37]

Spider-Man: India Edit

Spider-Man: India features Nalin Oberoi, a ruthless businessman in Mumbai, who is ravaging villages for a mystical amulet to connect with evil, supernatural demons who once ruled the world. [38] The process works and transforms Oberoi into "Green Goblin". He also transforms a meek doctor into "Doctor Octopus" and sends him to find Pavitar Prabhakar (Spider-Man). Oberoi later burns down Pavitar's village (branding it with his initials NO), and kidnaps MJ, and Aunt Maya (Aunt May). [39] At Oberoi HQ, he tries to bring down the demons, until a reformed Octopus and Pavitar attack and rescue the ladies. After killing the doctor, Oberoi is later defeated by Pavitar. [40] Oberoi also has a son mentioned by Pavitar, Hari. [40]


The term "Drosophila", meaning "dew-loving", is a modern scientific Latin adaptation from Greek words δρόσος , drósos, "dew", and φίλος , phílos, "loving" with the Latin feminine suffix -a.

Drosophila species are small flies, typically pale yellow to reddish brown to black, with red eyes. When the eyes (essentially a film of lenses) are removed, the brain is revealed. Drosophila brain structure and function develop and age significantly from larval to adult stage. Developing brain structures make these flies a prime candidate for neuro-genetic research. [4] Many species, including the noted Hawaiian picture-wings, have distinct black patterns on the wings. The plumose (feathery) arista, bristling of the head and thorax, and wing venation are characters used to diagnose the family. Most are small, about 2–4 millimetres (0.079–0.157 in) long, but some, especially many of the Hawaiian species, are larger than a house fly.

Environmental challenge by natural toxins helped to prepare Drosophilae to detox DDT, ​ [L 1] ​ [L 2] ​ [L 3] by shaping the glutathione S-transferase mechanism ​ [L 2] ​ [L 3] that metabolizes both. ​ [L 1] ​ [5]

Habitat Edit

Drosophila species are found all around the world, with more species in the tropical regions. Drosophila made their way to the Hawaiian Islands and radiated into over 800 species. [6] They can be found in deserts, tropical rainforest, cities, swamps, and alpine zones. Some northern species hibernate. The northern species D. montana is the best cold-adapted, [7] and is primarily found at high altitudes. [8] Most species breed in various kinds of decaying plant and fungal material, including fruit, bark, slime fluxes, flowers, and mushrooms. The larvae of at least one species, D. suzukii, can also feed in fresh fruit and can sometimes be a pest. [9] A few species have switched to being parasites or predators. Many species can be attracted to baits of fermented bananas or mushrooms, but others are not attracted to any kind of baits. Males may congregate at patches of suitable breeding substrate to compete for the females, or form leks, conducting courtship in an area separate from breeding sites. [ citation needed ]

Several Drosophila species, including D. melanogaster, D. immigrans, and D. simulans, are closely associated with humans, and are often referred to as domestic species. These and other species (D. subobscura, Zaprionus indianus [10] [11] [12] ) have been accidentally introduced around the world by human activities such as fruit transports.

Reproduction Edit

Males of this genus are known to have the longest sperm cells of any studied organism on Earth, including one species, Drosophila bifurca, that has sperm cells that are 58 mm (2.3 in) long. [13] The cells are mostly tail, and are delivered to the females in tangled coils. The other members of the genus Drosophila also make relatively few giant sperm cells, with that of D. bifurca being the longest. [14] D. melanogaster sperm cells are a more modest 1.8 mm long, although this is still about 35 times longer than a human sperm. Several species in the D. melanogaster species group are known to mate by traumatic insemination. [15]

Drosophila species vary widely in their reproductive capacity. Those such as D. melanogaster that breed in large, relatively rare resources have ovaries that mature 10–20 eggs at a time, so that they can be laid together on one site. Others that breed in more-abundant but less nutritious substrates, such as leaves, may only lay one egg per day. The eggs have one or more respiratory filaments near the anterior end the tips of these extend above the surface and allow oxygen to reach the embryo. Larvae feed not on the vegetable matter itself, but on the yeasts and microorganisms present on the decaying breeding substrate. Development time varies widely between species (between 7 and more than 60 days) and depends on the environmental factors such as temperature, breeding substrate, and crowding.

Fruit flies lay eggs in response to environmental cycles. Eggs laid at a time (e.g., night) during which likelihood of survival is greater than in eggs laid at other times (e.g., day) yield more larvae than eggs that were laid at those times. Ceteris paribus, the habit of laying eggs at this 'advantageous' time would yield more surviving offspring, and more grandchildren, than the habit of laying eggs during other times. This differential reproductive success would cause D. melanogaster to adapt to environmental cycles, because this behavior has a major reproductive advantage. [16]

Their median lifespan is 35–45 days. [17]

Mating systems Edit

Courtship behavior Edit

The following section is based on the following Drosophila species: Drosophila simulans, and Drosophila melanogaster.

Courtship behavior of male Drosophila is an attractive behaviour. [18] Females respond via their perception of the behavior portrayed by the male. [19] Male and female Drosophila use a variety of sensory cues to initiate and assess courtship readiness of a potential mate. [18] [19] [20] The cues include the following behaviours: positioning, pheromone excretion, following females, making tapping sounds with legs, singing, wing spreading, creating wing vibrations, genitalia licking, bending the stomach, attempt to copulate, and the copulatory act itself. [21] [18] [19] [20] The songs of Drosophila melanogaster and Drosophila simulans have been studied extensively. These luring songs are sinusoidal in nature and varies within and between species. [20]

The courtship behavior of Drosophila melanogaster has also been assessed for sex-related genes, which have been implicated in courtship behavior in both the male and female. [18] Recent experiments explore the role of fruitless (fru) and doublesex (dsx), a group of sex-behaviour linked genes. [22] [18]

The fruitless (fru) gene in Drosophila helps regulate the network for male courtship behavior when a mutation to this gene occurs altered same sex sexual behavior in males is observed. [23] Male Drosophila with the fru mutation direct their courtship towards other males as opposed to typical courtship, which would be directed towards females. [24] Loss of the fru mutation leads back to the typical courtship behavior. [24]

Polyandry Edit

The following section is based on the following Drosophila species: Drosophila serrata, Drosophila pseudoobscura, Drosophila melanogaster, and Drosophila neotestacea. Polyandry is a prominent mating system among Drosophila. [25] [26] [27] [28] Females mating with multiple sex partners has been a beneficial mating strategy for Drosophila. [25] [26] [27] [28] The benefits include both pre and post copulatory mating. Pre-copulatory strategies are the behaviours associated with mate choice and the genetic contributions, such as production of gametes, that are exhibited by both male and female Drosophila regarding mate choice. [25] [26] Post copulatory strategies include sperm competition, mating frequency, and sex-ratio meiotic drive. [25] [26] [27] [28]

These lists are not inclusive. Polyandry among the Drosophila pseudoobscura in North America vary in their number of mating partners. [27] There is a connection between the number of time females choose to mate and chromosomal variants of the third chromosome. [27] It is believed that the presence of the inverted polymorphism is why re-mating by females occurs. [27] The stability of these polymorphisms may be related to the sex-ratio meiotic drive. [28]

However, for Drosophila subobscura, the main mating system is monandry, not normally seen in Drosophila. [29]

Sperm competition Edit

The following section is based on the following Drosophila species: Drosophila melanogaster, Drosophila simulans, and Drosophila mauritiana. Sperm competition is a process that polyandrous Drosophila females use to increase the fitness of their offspring. [30] [31] [32] [33] [34] The female Drosophila has two sperm storage organs that allows her to choose the sperm that will be used to inseminate her eggs. [34] Females have little control when it comes to cryptic female choice. [33] [31] Female Drosophila through cryptic choice, one of several post-copulatory mechanisms, which allows for the detection and expelling of sperm that reduces inbreeding possibilities. [32] [31] Manier et al. 2013 has categorized the post copulatory sexual selection of Drosophila melanogaster, Drosophila simulans, and Drosophila mauritiana into the following three stages: insemination, sperm storage, and fertilizable sperm. [33] Among the preceding species there are variations at each stage that play a role in the natural selection process. [33]

Laboratory-cultured animals Edit

D. melanogaster is a popular experimental animal because it is easily cultured en masse out of the wild, has a short generation time, and mutant animals are readily obtainable. In 1906, Thomas Hunt Morgan began his work on D. melanogaster and reported his first finding of a white eyed mutant in 1910 to the academic community. He was in search of a model organism to study genetic heredity and required a species that could randomly acquire genetic mutation that would visibly manifest as morphological changes in the adult animal. His work on Drosophila earned him the 1933 Nobel Prize in Medicine for identifying chromosomes as the vector of inheritance for genes. This and other Drosophila species are widely used in studies of genetics, embryogenesis, chronobiology, speciation, neurobiology, and other areas. [ citation needed ]

However, some species of Drosophila are difficult to culture in the laboratory, often because they breed on a single specific host in the wild. For some, it can be done with particular recipes for rearing media, or by introducing chemicals such as sterols that are found in the natural host for others, it is (so far) impossible. In some cases, the larvae can develop on normal Drosophila lab medium, but the female will not lay eggs for these it is often simply a matter of putting in a small piece of the natural host to receive the eggs. [ citation needed ]

The Drosophila Species Stock Center located at Cornell University in Ithaca, New York, maintains cultures of hundreds of species for researchers. [35]

Use in genetic research Edit

Drosophila is considered one of the most impeccable genetic model organisms, they have furthered genetic research unlike any other model organisms. Drosophila is a prime candidate for genetic research because the relationship between human and fruit fly genes is very close. [36] Human and fruit fly genes are so similar, that disease-producing genes in humans can be linked to those in flies. The fly has approximately 15,500 genes on its four chromosomes, whereas humans have about 22,000 genes among their 23 chromosomes. Thus the density of genes per chromosome in Drosophila is higher than the human genome. [37] Low and manageable number of chromosomes make Drosophila species easier to study. These flies also carry genetic information and pass down traits throughout generations, much like their human counterparts. The traits can then be studied through different Drosophila lineages and the findings can be applied to deduce genetic trends in humans. Research conducted on Drosophila help determine the ground rules for transmission of genes in many organisms. [38] [4] Drosophila is a useful in vivo tool to analyze Alzheimer's disease. [39] Rhomboid proteases were first detected in Drosophila but then found to be highly conserved across eukaryotes, mitochondrion, and bacteria. [40] [41]

Microbiome Edit

Like other animals, Drosophila is associated with various bacteria in its gut. The fly gut microbiota or microbiome seems to have a central influence on Drosophila fitness and life history characteristics. The microbiota in the gut of Drosophila represents an active current research field.

Drosophila species also harbour vertically transmitted endosymbionts, such as Wolbachia and Spiroplasma. These endosymbionts can act as reproductive manipulators, such as cytoplasmic incompatibility induced by Wolbachia or male-killing induced by the D. melanogaster Spiroplasma poulsonii (named MSRO). The male-killing factor of the D. melanogaster MSRO strain was discovered in 2018, solving a decades-old mystery of the cause of male-killing. This represents the first bacterial factor that affects eukaryotic cells in a sex-specific fashion, and is the first mechanism identified for male-killing phenotypes. [42] Alternatively, they may protect theirs hosts from infection. Drosophila Wolbachia can reduce viral loads upon infection, and is explored as a mechanism of controlling viral diseases (e.g. Dengue fever) by transferring these Wolbachia to disease-vector mosquitoes. [43] The S. poulsonii strain of Drosophila neotestacea protects its host from parasitic wasps and nematodes using toxins that preferentially attack the parasites instead of the host. [44] [45] [46]

Predators Edit

Drosophila species are prey for many generalist predators, such as robber flies. In Hawaii, the introduction of yellowjackets from mainland United States has led to the decline of many of the larger species. The larvae are preyed on by other fly larvae, staphylinid beetles, and ants. [ citation needed ]

As with many Eukaryotes, this genus is known to express SNAREs, and as with several others the components of the SNARE complex are known to be somewhat substitutable: Although the loss of SNAP-25 - a component of neuronal SNAREs - is lethal, SNAP-24 can fully replace it. For another example, an R-SNARE not normally found in synapses can substitute for synaptobrevin. [47]


Sexual cannibalism is common among insects, arachnids [9] and amphipods. [9] There is also evidence of sexual cannibalism in gastropods and copepods. [10] Sexual cannibalism is common among species with prominent sexual size dimorphism (SSD) extreme SSD likely drives this trait of sexual cannibalism in spiders. [11]

Although females often instigate sexual cannibalism, reversed sexual cannibalism has been observed in the spiders Micaria sociabilis [12] [13] and Allocosa brasiliensis. [14] [15] In a laboratory experiment on M. sociabilis, males preferred to eat older females. This behavior may be interpreted as adaptive foraging, because older females have low reproductive potential and food may be limited. Reversed cannibalism in M. sociabilis may also be influenced by size dimorphism. Males and females are similar sizes, and bigger males were more likely to be cannibalistic. [13] In A. brasiliensis males tend to be cannibalistic in between mating seasons, after they have mated, gone out of their burrows to search for food, and left their mates in their burrows. Any females they cross during this period likely have little reproductive value, so this may also be interpreted as adaptive foraging. [15]

Different hypotheses have been proposed to explain sexual cannibalism, namely adaptive foraging, aggressive spillover, mate choice, and mistaken identity.

Adaptive foraging Edit

The adaptive foraging hypothesis is a proposed pre-copulatory explanation in which females assess the nutritional value of a male compared to the male's value as a mate. [16] Starving females are usually in poor physical condition and are therefore more likely to cannibalize a male than to mate with him. [17] Among mantises, cannibalism by female Pseudomantis albofimbriata improves fecundity, overall growth, and body condition. [16] A study on the Chinese mantis found that cannibalism occurred in up to 50% of matings. [18] Among spiders, Dolomedes triton females in need of additional energy and nutrients for egg development choose to consume the closest nutritional source, even if this means cannibalizing a potential mate. [19] In Agelenopsis pennsylvanica and Lycosa tarantula, a significant increase in fecundity, egg case size, hatching success, and survivor-ship of offspring has been observed when hungry females choose to cannibalize smaller males before copulating with larger, genetically superior males. [20] [21] This reproductive success was largely due to the increased energy uptake by cannibalizing males and investing that additional energy in the development of larger, higher-quality egg cases. [20] [22] In D. triton, post-copulatory sexual cannibalism was observed in the females that had a limited food source these females copulated with the males and then cannibalized them. [19]

The adaptive foraging hypothesis has been criticized because males are considered poor meals when compared to crickets however, recent findings discovered Hogna helluo males have nutrients crickets lack, including various proteins and lipids. [22] [23] In H. helluo, females have a higher protein diet when cannibalizing males than when consuming only house crickets. [22] Further studies show that Argiope keyserlingi females with high-protein/low-lipid diets resulting from sexual cannibalism may produce eggs of greater egg energy density (yolk investment). [3]

Aggressive spillover Edit

The aggressive spillover hypothesis suggests that the more aggressive a female is concerning prey, the more likely the female is to cannibalize a potential mate. [19] The decision of a female to cannibalize a male is not defined by the nutritional value or genetic advantage (courtship dances, male aggressiveness, & large body size) of males but instead depends strictly on her aggressive state. [9] [19] Aggression of the female is measured by latency (speed) of attack on prey. The faster the speed of attack and consumption of prey, the higher the aggressiveness level. [24] Females displaying aggressive characteristics tend to grow larger than other females and display continuous cannibalistic behavior. Such behavior may drive away potential mates, reducing chances of mating. [25] Aggressive behavior is less common in an environment that is female-biased, because there is more competition to mate with a male. In these female dominated environments, such aggressive behavior comes with the risk of scaring away potential mates. [21] [26]

Males of the Pisaura mirabilis species feign death to avoid being cannibalized by a female prior to copulation. [10] When males feign death, their success in reproduction depends on the level of aggressiveness the female displays. [10] [27] Research has shown that in the Nephilengys livida species, female aggressiveness had no effect on the likelihood of her cannibalizing a potential mate male aggressiveness and male-male competition determined which male the female cannibalized. Males with aggressive characteristics were favored and had a higher chance of mating with a female. [23]

Mate choice Edit

Females exercise mate choice, rejecting unwanted and unfit males by cannibalizing them. [28] [29] Mate choice often correlates size with fitness level smaller males tend to be less aggressive and display a low level of fitness smaller males are therefore eaten more often because of their undesirable traits. [28] Males perform elaborate courtship dances to display fitness and genetic advantage. [30] Female orb-web spiders (Nephilengys livida) tend to cannibalize males displaying less aggressive behavior and mate with males displaying more aggressive behavior, showing a preference for this trait, [23] which, along with large body size that indicates a strong foraging ability, displays high male quality and genetic advantage. [23] [31]

Indirect mate choice can be witnessed in fishing spiders, Dolomedes fimbriatus, where females do not discriminate against smaller body size, attacking males of all sizes. Females had lower success rates cannibalizing large males, which managed to escape where smaller males could not. [4] It was shown that males with desirable traits (large body size, high aggression, and long courtship dances) had longer copulation duration than males with undesirable traits. [23] [31] In A. keyserlingi and Nephila edulis females allow longer copulation duration and a second copulation for smaller males. [32] The gravity hypothesis suggests that some species of spiders may favor smaller body sizes because they enable them to climb up plants more efficiently and find a mate faster. [33] Also smaller males may be favored because they hatch and mature faster, giving them a direct advantage in finding and mating with a female. [34] In Leucauge mariana females will cannibalize males if their sexual performance was poor. They use palpal inflations to determine sperm count and if the female deems sperm count too low she will consume the male. [35] In Latrodectus revivensis females tend to limit copulation duration for small males and deny them a second copulation, showing preference for larger body size. [31] Another form of mate choice is the genetic bet-hedging hypothesis in which a female consumes males to prevent them from exploiting her. [36] It is not beneficial for a female exploited by multiple males because it may result in prey theft, reduction in web, and reduced time of foraging. [37] Sexual cannibalism might have promoted the evolution of some behavioral and morphological traits exhibited by spiders today. [31]

Mistaken identity Edit

The mistaken identity hypothesis suggests that sexual cannibalism occurs when females fail to identify males that try to court. [5] This hypothesis suggests that a cannibalistic female attacks and consumes the male without the knowledge of mate quality. In pre-copulatory sexual cannibalism, mistaken identity can be seen when a female does not allow the male to perform the courtship dance and engages in attack. [19] There is no conclusive evidence for this hypothesis because scientists struggle to distinguish between mistaken identity and the other hypotheses (aggressive spillover, adaptive foraging, and mate choice). [38]

In some cases, sexual cannibalism may characterize an extreme form of male monogamy, in which the male sacrifices itself to the female. Males may gain reproductive success from being cannibalized by either providing nutrients to the female (indirectly to the offspring), or through enhancing the probability that their sperm is used to fertilize the female's eggs. [39] Although sexual cannibalism is fairly common in spiders, male self-sacrifice has only been reported in six genera of araneoid spiders. However, much of the evidence for male complicity in such cannibalistic behavior may be anecdotal, and has not been replicated in experimental and behavioral studies. [40]

Male members of cannibalistic species have adapted different mating tactics as a mechanism for escaping the cannibalistic tendencies of their female counterparts. Current theory suggests antagonistic co-evolution has occurred, where adaptations seen in one sex produce adaptations in the other. [8] Adaptations consist of courtship displays, opportunistic mating tactics, and mate binding.

Opportunistic mating Edit

The risk of cannibalism becomes greatly reduced when opportunistic mating is practiced. [8] Opportunistic mating has been characterized in numerous orb-weaving spider species, such as Nephila fenestrata, where the male spider waits until the female is feeding or distracted, and then proceeds with copulation this greatly reduces the chances of cannibalization. This distraction can be facilitated by the male's presentation of nuptial gifts, where they provide a distracting meal for the female in order to prolong copulation and increase paternity. [8]

Altered sexual approach Edit

Multiple methods of sexual approaches have appeared in cannibalistic species as a result of sexual cannibalism. [41] The mechanism by which the male approaches the female is imperative for his survival. If the female is unable to detect his presence, the male is less likely to face cannibalization. This is evident in the mantid species, Tenodera aridifolia, where the male alters his approach utilizing the surrounding windy conditions. The male attempts to avoid detection by approaching the female when the wind impairs her ability to hear him. [42] In the praying mantid species Pseudomantis albofimbrata, the males approach the female either from a "slow mounting from the rear" or a "slow approach from the front" position to remain undetected. [41] The male alters his approach through the utilization of the surrounding windy conditions, and thus the risk of facing cannibalization is reduced. [41]

Mate guarding Edit

Sexual cannibalism has impaired the ability of the orb-weaving spider, N. fenestrata, to perform mate guarding. If a male successfully mates with a female, he then exhibits mate guarding, inhibiting the female from re-mating, thus ensuring his paternity and eliminating sperm competition. [43] Guarding can refer to the blockage of female genital openings to prevent further insertion of a competing male's pedipalps, or physical guarding from potential mates. Guarding can decrease female re-mating by fifty percent. [8] Males who experience genital mutilation can sometimes exhibit the "gloves off" hypothesis which states that a male's body weight and his endurance are inversely proportional. Thus when a male's body weight decreases substantially, his endurance increases as a result, allowing him to guard his female mate with increased efficiency. [44]

Mate binding Edit

Mate binding refers to a pre-copulatory courtship behavior where the male deposits silk onto the abdomen of the female while simultaneously massaging her in order to reduce her aggressive behavior. This action allows for initial and subsequent copulatory bouts. [7] While both chemical and tactile cues are important factors for reducing cannibalistic behaviors, the latter functions as a resource to calm the female, exhibited in the orb-weaver spider species, Nephila pilipes. [7] Additional hypotheses suggest that male silk contains pheromones which seduce the female into submission. However, silk deposits are not necessary for successful copulation. [7] The primary factor in successful subsequent copulation lies in the tactile communication between the male and female spider that results in female acceptance of the male. [45] The male mounts the posterior portion of the female's abdomen, while rubbing his spinnerets on her abdomen during his attempt at copulation. [7] Mate binding was not necessary for the initiation of copulation in the golden orb-weaving spider, except when the female was resistant to mating. Subsequent copulatory bouts are imperative for the male's ability to copulate due to prolonged sperm transfer, therefore increasing his probability of paternity. [7]

Courtship displays Edit

Courtship displays in sexually cannibalistic spiders are imperative in order to ensure the female is less aggressive. Additional courtship displays include pre-copulatory dances such as those observed in the redback spider, and vibrant male coloration morphologies which function as female attraction mechanisms, as seen in the peacock spider, Maratus volans. [45] Nuptial gifts play a vital role in safe copulation for males in some species. Males present meals to the female to facilitate opportunistic mating while the female is distracted. [8] Subsequent improvements in male adaptive mating success include web reduction, as seen in the Western black widow, Latrodectus hesperus. [46] Once mating occurs, the males destroy a large portion of the female's web to discourage the female from future mating, thus reducing polyandry, which has been observed in the Australian redback spider, Latrodectus hasselti. [47]

Male-induced cataleptic state Edit

In some species of spiders, such as Agelenopsis aperta, the male induces a passive state in the female prior to copulation. [48] It has been hypothesized that the cause of this "quiescent" state is the male's massaging of the female's abdomen, following male vibratory signals on the web. The female enters a passive state, and the male's risk of facing cannibalism is reduced. This state is most likely induced as a result of a male volatile pheromone. [48] The chemical structure of the pheromone utilized by the male A. aperta is currently unknown however, physical contact is not necessary for the induced passive state. Eunuch males, or males with partially or fully removed palps, are unable to induce the passive state on females from a distance, but can induce quiescence upon physical contact with the female this suggests that the pheromone produced is potentially related to sperm production, since the male inserts sperm from his pedipalps, structures which are removed in eunuchs. [48] This adaptation has most likely evolved in response to the overly aggressive nature of female spiders.

Copulatory silk wrapping Edit

In order to avoid being consumed by the female, some male spiders may utilize their silk to physically bind the female spider. For example, in Pisaurina mira, also known as the nursery web spider, the male wraps the legs of the female in silk prior to and during copulation. While he holds legs III and IV of the female, he uses the silk to bind legs I and II. [49] Because the male spider legs play a significant role in copulation, longer leg lengths in male P. mira are generally favored over shorter lengths.

The physiological impacts of cannibalism on male fitness include his inability to father any offspring if he is unable to mate with a female. There are males in species of arachnids, such as N. plumipes, that sire more offspring if the male is cannibalized after or during mating copulation is prolonged and sperm transfer is increased. [43] In the species of orb-weaving spider, Argiope arantia, males prefer short copulation duration upon the first palp insertion in order to avoid cannibalism. Upon the second insertion, however, the male remains inserted in the female. The male exhibits a "programmed death" to function as a full-body genital plug. This causes it to become increasingly difficult for the female to remove him from her genital openings, discouraging her from mating with other males. [50] An additional benefit to cannibalization is the idea that a well-fed female is less likely to mate again. [51] If the female has no desire to mate again, the male who has already mated with her has his paternity ensured.

Genital mutilation Edit

Before or after copulating with females, certain males of spider species in the superfamily Araneoidea become half or full eunuchs with one or both of their pedipalps (male genitals) severed. This behavior is often seen in sexually cannibalistic spiders, causing them to exhibit the "eunuch phenomenon". [44] Due to the chance that they may be eaten during or after copulation, male spiders use genital mutilation to increase their chances of successful mating. The male can increase his chances of paternity if the female's copulatory organs are blocked, which decreases sperm competition and her chances of mating with other males. In one study, females with mating plugs had a 75% lower chance of re-mating. [52] Additionally, if a male successfully severs his pedipalp within the female copulatory duct the pedipalp can not only serve as a plug but can continue to release sperm to the female spermathacae, again increasing the male's chances of paternity. This is referred to as "remote copulation". [53] Occasionally (in 12% of cases in a 2012 study on Nephilidae spiders) palp severance is only partial due to copulation interruption by sexual cannibalism. Partial palp severance can result in a successful mating plug but not to the extent of full palp severance. [53] Some males, as in the orb-weaving spider, Argiope arantia, have been found to spontaneously die within fifteen minutes of their second copulation with a female. [50] The male dies while his pedipalps are still intact within the female, as well as still swollen from copulation. In this "programmed death", the male is able to utilize his entire body as a genital plug for the female, causing it to be much more difficult for her to remove him from her copulatory ducts. [50] In other species males voluntarily self-amputate a pedipalp prior to mating and thus the mutilation is not driven by sexual cannibalism. This has been hypothesized to be due to an increased fitness advantage of half or full eunuchs. Upon losing a pedipalp males experience a significant decrease in body weight that provides them with enhanced locomotor abilities and endurance, enabling them to better search for a mate and mate-guard after mating. This is referred to as the "gloves-off" theory. [54] Males and females have also been seen with the roles reversed in terms of genital mutilation. In Cyclosa argenteoalba, males mutilate female spider's genitals by detaching the female's scape, making it impossible for another male to mate with them.

Male reproductive success can be determined by their number of fathered offspring, and monogyny is seen quite often in sexually cannibalistic species. Males are willing to sacrifice themselves, or lose their reproductive organs in order to ensure their paternity from one mating instance. [50] [52] Whether it is by spontaneous programmed death, or the male catapulting into the mouth of the female, these self-sacrificing males die in order for prolonged copulation to occur. Males of many of these species cannot replenish sperm stores, therefore they must exhibit these extreme behaviors in order to ensure sperm transfer and fathered offspring during their one and only mating instance. An example of such behavior can be seen in the redback spider. The males of this species "somersault" into the mouths of the female after copulation has occurred, which has been shown to increase paternity by sixty-five percent when compared to males that are not cannibalized. A majority of males in this species are likely to die on the search for a mate, so the male must sacrifice himself as an offering if it means prolonged copulation and doubled paternity. In many species, cannibalized males can mate longer, thus having longer sperm transfers. [55]

Males in these mating systems are generally monogamous, if not bigynous. [44] Since males of these cannibalistic species have adapted to the extreme mating system, and usually mate only once with a polyandrous female, they are considered monogynous. [56]

Sexual dimorphism Edit

Sexual dimorphism in size has been proposed as an explanation for the widespread nature of sexual cannibalism across distantly related arthropods. Typically, male birds and mammals are larger as they participate in male-male competition. [57] However, in arthropods this size dimorphism ratio is reversed, with females commonly larger than males. Sexual cannibalism may have led to selection for larger, stronger females in invertebrates. [58] Further research is needed to evaluate the explanation. To date, studies have been done on wolf spiders such as Zyuzicosa (Lycosidae), where the female is much larger than the male. [59]

Uncanny similarity of unique inserts in the 2019-nCoV spike protein to HIV-1 gp120 and Gag

We are currently witnessing a major epidemic caused by the 2019 novel coronavirus (2019-nCoV). The evolution of 2019-nCoV remains elusive. We found 4 insertions in the spike glycoprotein (S) which are unique to the 2019-nCoV and are not present in other coronaviruses. Importantly, amino acid residues in all the 4 inserts have identity or similarity to those in the HIV-1 gp120 or HIV-1 Gag. Interestingly, despite the inserts being discontinuous on the primary amino acid sequence, 3D-modelling of the 2019-nCoV suggests that they converge to constitute the receptor binding site. The finding of 4 unique inserts in the 2019-nCoV, all of which have identity /similarity to amino acid residues in key structural proteins of HIV-1 is unlikely to be fortuitous in nature. This work provides yet unknown insights on 2019-nCoV and sheds light on the evolution and pathogenicity of this virus with important implications for diagnosis of this virus.


Genetics is defined as the study of genes. Genes are composed of deoxyribonucleic acid (DNA) that can be passed down and inherited from one generation to the next. The information encoded in DNA is critical for determining the properties of a species1. DNA is divided into discrete molecules called chromosomes, each of which contain numerous genes.

Figure 1. Non-disjunction during meiosis II results in two normal gametes, one n+1 gamete, and one n-1 gamete.

A ‘normal’ human cell is diploid (2n) because it contains 2 copies of each of the 23 chromosomes. Included in these 46 chromosomes are sex chromosomes X and Y. A normal human male has one X- and one Y- chromosome. They are often denoted 46, XY male. A normal human female has two X chromosomes, and is denoted 46, XX female.

In mitosis, in order for the cell to divide, it must replicate its DNA to create identical copies for its daughter cells. An example of mitosis is the development of the multicellular organisms from a single celled zygote (fertilized egg) [1]. Meiosis is essential for humans to produce sex cells (like sperm in men and eggs in women). It consists of two nuclear divisions resulting in haploid cells (n), which contain single copies of chromosomes. Haploid cells from a female and a male can fuse together to create a zygote with a unique combination of chromosomes. As indicated above, sex chromosome combinations include XX or XY.

Sex determination is genetically programmed by the X- and Y- chromosomes and is defined at the time of testes or ovary formation in embryonic development [2]. Testes formation in men is regulated by the expression of genes on the Y chromosome. Ovary formation occurs if the Y chromosome is not present and this DNA is not expressed. In addition to aiding in the development of primary sex characteristics mentioned above (sex organs involved in reproduction), the production of hormones like estrogen in women and testosterone in men is key for the development of secondary sex characteristics. Secondary sex characteristics develop later in life and often emphasize the assignment of female or male sex. Examples of secondary sex characteristics in females include enlarged breasts, wide hips, less facial hair than men, and subcutaneous fat [3]. Examples of secondary sex characteristics in males include chest and facial hair, deep voices, and a relatively larger body size [3]. These sex characteristics are important for humans to define their biological sex.

Figure 2. Non-disjunction during meiosis I results in two n+1 gametes and two n-1 gametes.

Biological sex is identified based on the external genitalia (i.e. penis or vagina) and gonads (i.e. testes or ovaries) present in an individual. In contrast, gender identity refers to the self-identification in the brain of an individual as female or male. Most of the time sex and gender identity go hand in hand. However, unusual genetics may lead to biological sex ambiguities, discrepancies, and gender identity confusion [4].

Non-disjunction in meiosis I or meiosis II can lead to aneuploidy, an abnormal condition when an organism’s chromosome number differs from wild-type (normal). The result of non-disjunction in meiosis I is two gametes (sex cells) with an extra chromosome (n + 1) and two gametes missing a chromosome (n – 1). The result of non-disjunction in meiosis II is one gamete with an extra chromosome (n + 1), one gamete missing a chromosome (n – 1), and two gametes with the correct number of chromosomes (n). Fusion of abnormal sex cells from males and females can create aneuploidal zygotes 1. There are several genetic disorders that are associated with aneuploidy and I will use Turner’s syndrome and Klinefelter syndrome as examples to show how aneuploidy affects sex and gender identity.

Figure 3. Mosaicism occurs when tissues contain two genetically different cell lines.

Turner’s syndrome: Affected individuals with Turner’s syndrome (TS) are genetically 45, X as they are completely or partially lacking a partner sex chromosome [1]. Cells that are completely lacking a partner sex chromosome have evolved from spontaneous non-disjunction during meiosis. Mosaicism occurs in females with TS when their tissues contain at least 2 different cell lines that differ genetically, but are derived from a single zygote5. This is caused by a separate non-disjunction event occuring shortly after fertilization. 45,X/46,XX and 45X/46,XY are examples of mosaicisms, but there are other possibilities6. TS females have several distinguishing characteristics such as infertility (inability to have children), short stature, webbed skin behind the neck, low hairline, widely spaced nipples, small breast development, brown spots, small finger nails, and ovarian failure1. The most obvious characteristics that lead to diagnosis are short stature and infertility.

Klinefelter’s syndrome: Affected individuals with Klinefelter syndrome are genetically 47,XXY [1]. The second X chromosome is often X-inactivated, meaning that it no longer functions to express its genes. Klinefelter syndrome develops when there is spontaneous non-disjunction in meiosis. Non-disjunction could occur either maternally (in the mother’s gamete) or paternally (in the father’s gamete) to create a 47,XXY zygote. Paternal non-disjunction in meiosis I accounts for 53% of cases, and maternal non-disjunction in meiosis I accounts for 34% of cases. The remainder of cases occur in meiosis II. 15% of people with Klinefelter syndrome are 47,XXY/46,XY mosaics. Klinefelter’s syndrome is normally diagnosed during puberty [7]. Generally men with Klinefelter’s syndrome can lead normal lives. They have several distinguishing characteristics such as sterility, tall stature, long arms and legs, lanky build, feminized physique, little chest hair, female patterned pubic hair, testicular atrophy, hypogonadism, osteoporosis, reduced aggression, language deficits, and breast development [1]. The low level of testosterone accounts for the lack of development of male secondary sex characteristics.

At first glance sex identification appears simple. However, with closer examination it is clear that aneuploidy is always a possibility and can make sex identification ambiguous and complex. Perhaps further understanding of the biology of sexual differentiation will help our society realize that sex is not as clearcut as our ancestors would have us believe.

1. Griffiths AJF, Gelbart WM, Miller JH, Lewontin RC. Modern genetic analysis. W.H. Freeman and Company, New York 1999 p2, 91, 243

2. Cotinot C, Pailhoux E, Jaubert F, Fellous M. Molecular genetics of sex determination. Semin Reprod Med 2002 20(3):157-166

3. Wikipedia. Secondary sex characteristics. Online. Internet. April 1, 2004. Available.

4. GIRES. Gender dysphoria. Online. Internet. April 1, 2004.

5. Nussbaum RL, McInnes RR, Willard HF. Thompson and Thompson genetics in medicine. W.B. Saunders Company, Philadelphia 2001 p75, 176

6. Ostberg JE, Conway GS. Adulthood in women with Turner syndrome. Horm Res 2003 59: 211-221

7. Visootsak J, Aylstock M, Graham JM. Klinefelter syndrome and its variants: an update and review for the primary pediatrician. Clin Pediatr (Phila) 2001 40(12): 639-651

8. Bradley SJ, Zucker KJ. Gender identity disorder: a review of the past 10 years. J Am Acad Child Adolesc Psychiatry 1997 36:872-880

9. Batch J. Turner syndrome in childhood and adolescence. Best Practice & Research Clinical Endocrinology and Metabolism 2002 16(3): 465-482

10. Muhs A, Lieberz K. Anorexia nervosa and Turner’s syndrome. Psychopathology 1993 26: 29-40

11. El-Badri SM, Lewis MA. Anorexia nervosa associated with klinefelter’s syndrome. Comp Psych 1991 32(4): 317-319

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