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Parthenogenesis

Parthenogenesis is a form of reproduction in which the ovum develops into a new individual without fertilization. Natural parthenogenesis has been observed in many lower animals (it is characteristic of the rotifers), especially insects, e.g., the aphid . In many social insects, such as the honeybee and the ant, the unfertilized eggs give rise to the male drones and the fertilized eggs to the female workers and queens. It has also been observed in some snakes, fish, and monitor lizards. The phenomenon is rarer among plants (where it is called parthenocarpy) than among animals. Unusual patterns of heredity can occur in parthenogenetic organisms. For example, offspring produced by some types are identical in all inherited respects to the mother.

The phenomenon of parthenogenesis was discovered in the 18th cent. by Charles Bonnet . In 1900, Jacques Loeb accomplished the first clear case of artificial parthenogenesis when he pricked unfertilized frog eggs with a needle and found that in some cases normal embryonic development ensued. Artificial parthenogenesis has since been achieved in almost all major groups of animals, although it usually results in incomplete and abnormal development. Numerous mechanical and chemical agents have been used to stimulate unfertilized eggs. In 1936, Gregory Pincus induced parthenogenesis in mammalian (rabbit) eggs by temperature change and chemical agents. No successful experiments with human parthenogenesis have been reported.[1]

There are 10 known Parthenogenetic scorpion species thus far:

• Ananteris coineaui[5]
• Hottentotta caboverdensis
• Hottentotta hottentotta
• Liocheles australasiae
• Tityus columbianus
• Tityus metuendus
• Tityus serrulatus
• Tityus stigmurus
• Tityus trivittatus
• Tityus urugayensis

And there are currently 3 known types of parthenogenesis:

Arrhenotoky The phenomenon occurring in the reproduction of certain animals in which fertilized eggs give rise to females and unfertilized eggs to males [2]

Deuterotoky A form of parthenogenesis in which the female has offspring of both sexes.[3]

Thelytoky Parthenogenesis in which only female offspring are produced [4]

Resources

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SCORPIONS, SCORPIONISM, LIFE HISTORY STRATEGIES AND PARTHENOGENESIS

1. The Columbia Encyclopedia, Sixth Edition 2007

2. Oxford Dictionary of Biology, 2004

3. The Centre for Cancer Education, Online Medical Dictionary

4. Merriam-Webster Medical Dictionary

5. A NEW ALL-FEMALE SCORPION AND THE FIRST PROBABLE CASE OF ARRHENOTOKY IN SCORPIONS

External links (Additional Non-Scorpion References)

• Parthenogenesis of Mice at Nature.com

• Reproductive behavior in whiptails at Crews Laboratory

• Types of asexual reproduction

• Parthenogenesis in Incubated Turkey Eggs from Oregon State University

• National Geographic NEWS: Virgin Birth Expected at Christmas -- By Komodo Dragon

• BBC NEWS: 'Virgin births' for giant lizards (Komodo dragon)

• REUTERS: Komodo dragon proud mum (and dad) of five

• Female sharks capable of virgin birth

• Marmorkrebs.org

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