Female Penis, Male Vagina: First Case of Genital Reversal in Nature Reported By Charles Q. Choi, Live Science Contributor | April 17, 2014 11:42am ET
Shown here, the female penis structure of the cave insect Neotrogla aurora.
Credit: Current Biology, Yoshizawa et al.[url=]View full size image[/url]
Females with penislike genitals and males with vaginalike organs are cases of a new extreme reversal of sex roles researchers have discovered in little-known cave insects.
These are the first examples of animals with genitalia that reverse the traditional sex roles, and the discovery could shed light on the conflict between the sexes in the animal kingdom, investigators said.
Scientists analyzed four species of insects from extremely dry caves in Brazil. All four species belong to the genus Neotrogla, just as dogs, wolves, coyotes and jackals belong to genus Canis. The first Neotroglawas discovered 18 years ago; adult Neotrogla range from about 2.7 to 3.7 millimeters (0.11 to 0.15 inches) long. [See Photos of the Genital-Reversed Cave Insects]
The researchers were astonished to discover that the females of these species had penislike genitals dubbed gynosomes, a complex organ composed of muscles, ducts, membranes and spikes. In contrast, the males possess vaginalike phallosomes.
[url=][/url] Females with penislike genitals and males with vaginalike organs are cases of a new extreme reversal of sex roles researchers have discovered in little-known cave insects of the genus Neotrogla. Credit: Current Biology, Yoshizawa et al.[url=]View full size image[/url]
"Neotrogla species constitute the first cases in nature in which genitalia are reversed," said study co-author Rodrigo Ferreira, a cave biologist at the Federal University of Lavras in Brazil.
The gynosome is a "completely novel structure in evolution," said lead study author Kazunori Yoshizawa, an entomologist at Hokkaido University in Japan. "Evolution of such novelties is exceptionally rare, maybe comparable with the origin of insect wings."
At about 0.4 to 0.5 mm (0.016 to 0.02 inches), or about one-seventh the length of the insects, the penislike organs are large relative to the size of the insects. That would be the equivalent of a man who is 5 feet 9 inches (1.75 meters) tall having a penis about 9.8 inches (24.9 centimeters) long. (The average penis size for American men is 5.6 inches, or 14.2 cm.)
During copulation, which lasts a whopping 40 to 70 hours, the females insert their gynosomes into the male organs. The intricate female organs collect sperm capsules from the males. [The 7 Weirdest Animal Penises]
Once inside a male, the membranous part of the female gynosome inflates, and numerous spines on the organ anchor the two insects together. Females can hold males very tightly — in one instance, when the scientists attempted to pull a pair apart, the male's abdomen was ripped from the rest of his body without breaking the genital coupling.
Evolution of sex-role reversal
Usually, a new biological structure evolves as a modification of a previously existing structure. In contrast, there is no biological structure known elsewhere among females in the animal kingdom that is analogous to the gynosome, Yoshizawa said.
The researchers suspect this strange reversal of sex roles evolved because of the generous amounts of nutritious semen that males include within their sperm capsules as nuptial gifts for their mates. The caves in which these insects live are poor in resources, making it advantageous for females to mate more often.
"It is very likely that female Neotrogla can coercively grasp and copulate with a reluctant male," Yoshizawa told Live Science. "In animals, coercive mating is generally an exclusive feature of males."
The long times spent copulating may also be due to the harsh nature of the caves.
"Longer matings can allow a higher amount of semen to be transferred," Ferreira told Live Science.
Sex roles are occasionally reversed in the animal kingdom. For instance, male seahorses typically raise offspring in brooding pouches. And for some mites, the female genitals are long tubes used to receive sperm. However, these mite genitals lack the anchors seen in gynosomes, so they cannot be used to coerce sex as Neotrogla do.
Future research could further investigate the unique sex lives of these cave insects to explore ideas regarding the conflict between the sexes in the animal kingdom. One interesting question has to do with how male Neotrogla deal with coercive sex.
In other species, when females are coerced into sex, they can discard sperm from males they do not prefer, or seek out sperm from males they do prefer, "but these options are not available for male Neotrogla, because males do not receive eggs from females," Yoshizawa said. "How do males respond to coercive matings by females?" Yoshizawa asked.
The researchers do not yet have direct evidence to answer this question. However, they speculate that male Neotrogla might control how nutritious their nuptial gifts are depending on the quality of their mates.
Many caves left to explore
These odd discoveries could be the first of many from Brazilian caves. In recent years, scientists have uncovered dozens of new species in these caverns.
"This indicates the huge potential that Brazil possesses regarding cave fauna," Ferreira said. "Brazil might have more than 150,000 caves."
"The Brazilian laws regarding cave protection have changed in recent years and now the caves, which used to be protected, are under risk," Ferreira said. "Many new species, some of which could bring huge advances for science — biology, evolution or even some of biotechnological interest — are threatened. Many species are under the risk of extinction even before being discovered."
The scientists detailed their findings April 17 in the journal Current Biology.
[size=1.1em]Scientists research a little-known Brazilian insect who shows extreme gender role reversal when it comes to mating rituals
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70 hour sex sessions: The Neotrogla female has a penis like organ, which she uses to "mate" with her male partner
[size=1.1em]Girls will be boys and boys will be girls, but a little-known Brazilian insect takes role reversal to a whole new level.
[size=1.1em]Scientists researching the cave-dwelling Neotrogla say the female sports an impressive penis, which she uses to "mate" with her male partner.
[size=1.1em]He, on the other hand, is blessed with what the researchers describe as a "much-reduced, vagina-like opening".
[size=1.1em]As if that does not make the insect's sex life interesting enough, copulation between the two sexes can last up to 70 hours.
[size=1.1em]"Although sex-role reversal has been identified in several different animals, Neotrogla is the only example in which the intromittent organ is also reversed," said lead scientist Dr Kazunori Yoshizawa, from Hokkaido University in Japan.
[size=1.1em]A study of four species of the Neotrogla showed that the penis-like structure of the female, called a gynosome, is inserted into males and used to receive capsules of nutrient and sperm.
[size=1.1em]Once within a male, the part inflates and projects spines which anchor the two insects together.
[size=1.1em]The scientists found it impossible to pull coupling males and females apart without causing injury.
[size=1.1em]Their description of Neotrogla's strange mating habits is published in the journal Current Biology.
Ditemukan serangga betina memiliki penis
Terbaru 19 April 2014 - 13:47 WIB
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Organ "penis" milik serangga betina menyedot sperma pejantan.
Sebuah spesies serangga betina memiliki "penis" telah ditemukan di Brasil, yang menurut ilmuwan merupakan contoh pertama hewan yang memiliki alat kelamin terbalik.
Termasuk dalam kategori genus Neotrogla, serangga betina tersebut memiliki organ yang ketika ereksi panjangnya mencapai 3 milimeter, layaknya milik serangga jantan.
Hasil penelitian yang diterbitkan jurnal Current Biology menyebutkan, persetubuhan (copulation) itu berlangsung impresif karena berlangsung antara 40-70 jam.Memiliki struktur rumit, dijuluki sebagai "gynosome", organ itu digunakan serangga betina itu untuk menghisap sperma atau air mani yang bergizi.
"Walaupun terjadi pembalikan peran seks yang telah diidentifikasi pada beberapa hewan yang berbeda, Neotrogla adalah satu-satunya contoh di mana organ intromittent juga terbalik," kata pimpinan penelitian, Kazunori Yoshizawa dari Universitas Hokkaido di Jepang.
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Kemampuan persetubuhan serangga betina bertahan sampai 70 jam.
Serangga yang "memutarbalikkan" istilah gender ini ditemukan di sebuah gua di timur laut Brasil. Mereka mewakili empat spesies yang berbeda dalam genus Neotrogla.
Seperti jangkar dan berduri
Hasil penelitian menunjukan, setelah organ "penis" serangga betina itu masuk ke organ pejantan, bagian membran dari gynosome betina itu lantas mengembang.
Alat itu terlihat seperti jangkar yang memiliki banyak duri.
Ketika tim peneliti mencoba untuk memisahkan persetubuhan antara pejantan dan betina, perut pejantan robek tanpa merusak alat genitalnya.
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Gambar ketika persetubuhan antara serangga betina "berpenis" dan pejantan.
Para peneliti menduga, terjadinya pembalikan peran seksual itu barangkali diakibatkan lingkungan gua yang terbatas dan minim sumber daya.
Kesimpulan penelitian ini diharapkan dapat menawarkan pendekatan baru untuk menguji ide-ide tentang seleksi seksual, konflik antara dua jenis kelamin, dan teori evolusi baru.
Ditemukan, Serangga Betina BerpenisPeran seks terbalik telah diidentifikasi pada beberapa hewan.ddd
Minggu, 20 April 2014, 06:54
Eko Priliawito, Amal Nur Ngazis
Ilustrasiserangga
VIVAnews - Peneliti menemukan serangga aneh di Brasil, memiliki alat kelamin seks terbalik. Hewan yang diidentifikasi serangga betina itu diketahui memiliki penis. Serangga yang termasuk dalam genus Neotrogla itu ditemukan pada sebuah gua di timur laut Brasil.
Melansir stasiun berita BBC, Minggu 20 April 2014, peneliti mengamati perilaku serangga selama masa persetubuhan 40-70 jam. Serangga Neotrogla betina ternyata memasukkan organ ereksi itu ke lubang vagina. Struktur rumit yang dijuluki dengan gynosome itu digunakan untuk menghisap sperma dan cairan mani bergizi.
"Meski peran seks terbalik telah diidentifikasi pada beberapa hewan berbeda, Neotrogla merupakan satu-satunya contoh dimana organ pengirim sperma juga terbalik," jelas pemimpin studi, Kazunori Yoshizawa dari Hokkaido University, Jepang.
Setelah serangga jantan masuk, bagian membran gynosome betina mengembang. Kemudian saat peneliti berupaya memisah jantan dan betina, perut jantan robek dari dada tanpa merusak pasangan organ genital itu.
Peneliti berspekulasi hal yang mempengaruhi peran seks yang terbalik itu yakni lingkungan gua yang miskin sumber daya. Temuan serangga yang aneh itu memberikan peluang baru untuk menguji ide tentang seleksi seksual, konflik antara jenis kelamin dan evolusi baru.
"Serangga itu akan menjadi penting untuk mengungkapkan kenapa diantara banyak hewan yang memiliki peran seksual terbalik, hanya Neotrogla yang menguraikan penis betina," tambah Yoshitaka Kamimura, penelit dari Keio university, Jepang.
Temuan ini telah dilaporkan pada jurnal Current Biology.
Post time 20-4-2014 07:57 PM
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变色卡
lol Last edited by burque on 20-4-2014 08:22 PM 
