04-18-09, 06:05 PM #1
All Female Species Found
I don't understand. Does the queen just keep giving birth to herself and everyone is identical to her?
Why would they evolve that way.....unless.....males aren't needed??
This leaf-cutter ant species is all female and thrives without sex of any kind—ever—according to a new study. The ants have evolved to reproduce only when queens clone themselves.
"They appear to have evolved a new mode of reproduction, and the genetic mechanisms have yet to be worked out," said lead study author Anna Himler, a research associate at the University of Arizona.
In M. smithii the typical muscular reproductive organ of female ants has evolved into a "sort of a ghost of an organ at this point," Himler added.
No male of the species has ever been found, and "even if a male were theoretically to appear somewhere, we're not sure they could mate any more," she said.
Other ants, such as fire ants, that can reproduce asexually have working sexual organs, just in case.
M. smithii also has an idiosyncratic arrangement for that other apparent necessity: food. The ants, which range from northern Mexico to Argentina, are in a codependent relationship with a specific fungus.
"The fungus garden is quite wimpy," Himler said. "If you remove the ants, the gardens will quickly die."
The ants keep the gardens weeded, and they "feed" the fungus leaf bits, insect carcasses, and feces, which the ants clean and cut up before offering to the fungus. In return, the fungus provides the sole source of food for the ants' babies.
04-18-09, 06:12 PM #2
Those ants might one day be completely wiped out, for example by a single virus. If one isn't resistant, none of them is.
In Hymenopterans (bees, wasps, ants and sawflies) haplodiploidy is common. It means that fertilized eggs (diploid) will turn into females, while unfertilized eggs (haploid) will turn into males. Perhaps these ants somehow turned this system around.
Last edited by Enmos; 04-18-09 at 06:18 PM.
04-18-09, 06:17 PM #3
so even if they started from 1000 queens, their genetic diversity would still be an issue. Even if over a lifetime the various queens make-up had changed due to viruses, bacteria, etc.
04-18-09, 06:21 PM #4
04-18-09, 06:22 PM #5
By the way, researchers have claimed this kind of thing before, only to announce later that they found a male specimen.
In some insect species males are kind of elusive, since they are only alive for a short time during reproduction.
04-18-09, 06:23 PM #6
04-18-09, 06:24 PM #7
04-18-09, 06:26 PM #8
04-18-09, 06:27 PM #9
04-18-09, 06:28 PM #10
04-18-09, 06:37 PM #11
Parthenogenesis in insects can cover a wide range of mechanisms.
The different forms include:
1. Thelytoky - parthenogenesis in which only female offspring are produced and no mating is observed
2. Pseudogamy (or gynogenesis or sperm-dependent parthenogenesis) - here mating occurs and the eggs require activation by entry of sperm but only the maternal chromosomes are expressed
3. Automixis - parthenogenesis in which the eggs undergo meiosis
4. Apomixis - parthenogenesis in which the eggs do not undergo meiosis
Polyembryony is another process that produces multiple clonal offspring from a single egg. This is known in some hymenopteran parasitoids and in strepsiptera.
In automictic species the offspring can be haploid or diploid. Diploids are produced by doubling or fusion of gametes after meiosis. Fusion is seen in the Phasmatodea, Hemiptera (Aleurodids and Coccidae), Diptera, and some Hymenoptera.
In addition to these forms is hermaproditism, where both the eggs and sperm are produced by the same individual. This is seen in three species of Icerya scale insects.
Parasitic bacteria like Wolbachia have been noted to induce automictic thelytoky in many insect species with haplodiploid systems. They also cause gamete duplication in unfertilized eggs causing them to develop into female offspring.
04-18-09, 06:38 PM #12
04-18-09, 07:22 PM #13
04-18-09, 08:01 PM #14
04-18-09, 10:49 PM #15
With certain fish species--f'rinstance sticklebacks--the dominant female of the group can change sex and become male if the lead male fish of the group dies. Slightly off-subject, but interesting that it can happen.
04-19-09, 04:42 AM #16
04-19-09, 05:05 AM #17
some plants, bacteria, possably some sea creatures but no mamals, birds or reptiles definitly. part of the definition of a mamal is sexual reproduction
04-19-09, 05:07 AM #18
oh some coral reproduce by spliting and others reproduce sexually. some do both
04-19-09, 07:33 AM #19
Stories of beautiful and bloodthirsty female warrior women thundering across arid battlefields have been told, re-told and speculated over for thousands of years and by many cultures. Greek myths are filled with tales of the Amazons and their exploits, love affairs and battles with
Olympian gods like Zeus, Ares and Hera. Amazon warriors fought and died in the Trojan war. Homer and Hippocrates speculated over or wrote of these fierce fighting women, as did Greek historian Herodotus. The West African kingdom of Dahomey employed a legion of so-called Amazons who conquered cities for King Agaja during the 1600’s. Spanish adventurer, Francisco de Orellana, is said to have named South America’s greatest river, the Amazon, after a fierce tribe of warrior women he encountered along its banks.
Greek mythology describes the Amazons as descendants of the god of war, Ares, and the sea nymph, Harmonia. They worshipped Artemis, goddess of the hunt and exactly where the Amazons territory was has always been disputed. Herodotus believed they may have occupied the sweeping steppes of Southern Russia. Other stories claim they lived in Thrace or along the lower Caucasus Mountains in northern Albania. The Thermodon River, in Asia Minor, known today as the coast of Turkey, seems to be the most frequently mentioned territory of the Amazons.
Amazon society was stringently matriarchal. Males were of no use other than for mating purposes and as slaves, doing work that was traditionally performed by women. Mens’ outer extremities were often mutilated to prevent them taking up arms against their captors or escaping. Male babies were either given away at birth to neighbouring tribes or killed.
From an early age Amazons were trained in the arts of war. Some myths and stories say that during adolescence a young Amazon’s right breast would be cauterised or entirely removed by her mother so that once the girl reached adulthood she could wield bows and throw javelins more accurately. Experts disagree, claiming that the Amazons would not have had the medical know how to prevent massive haemorrhage or infection if such drastic mutilations actually occurred.
The Amazons were said to be the first humans to tame and ride horses. They were fearless and expert warriors, on horseback or as foot soldiers, and the Greeks fiercest enemies. They dedicated themselves to endless hours of training in the art of combat, their favored weapons, bows, spears and doubled-sided battle axes.
04-19-09, 07:39 AM #20
If there's no men, what do they find to talk about?
The song that gets them all out onto the dancefloor is called "It's Raining"
It goes like this:
"It's raining. Halleluliah.
Last edited by Captain Kremmen; 04-19-09 at 09:05 AM.
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