Amazon Parrot
| Amazon Parrot | ||||||||||||
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Amazon Parrot ( Poecilia "formosa" ) |
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| Poecilia "formosa" | ||||||||||||
| ( Girard , 1859) |
The Amazon Parrot ( Poecilia formosa ), also known as Amazon Molly , Pale Molly and Blasser Karpfling , is a representative of the viviparous toothcarps of which only females are known. Originally created through the hybridization of the Atlantic Parrot ( Poecilia mexicana ) with the Broadfin Parrot ( Poecilia latipinna ), the Parrot need sperm from males of closely related species in order to stimulate the development of the already diploid egg cells without using the father's genetic material. This form of reproduction is known as gynogenesis .
features
Amazon parsons reach an average length of 5.5 cm, the maximum is 9.6 cm in the literature. In terms of appearance, the fish stand exactly between the females of the broad-fin fish and the Atlantic fish. They are inconspicuously silvery-white, the fins are colorless. The dorsal fin has 11 fin rays, in the Atlantic larva there are 9, in the broad-finned larva there are 13.
Occurrence and way of life
The Amazon Parrot (sometimes incorrectly called "Amazon Parrot") occurs in a narrowly limited area between the Nueces River in southeast Texas and the mouth of the Río Tuxpan north of the Sierra del Abra in Mexico . Outside of the natural range, there are still stable populations in the catchment area of the San Marcos River in central Texas. The fish are tolerant of the salinity of the water, but, unlike the common finfish, have not yet been detected in brackish water .
Since the females are dependent on sperm from males of related species for reproduction, they can only survive where there are suitable copulatory partners. In the natural range, these are males of the parent species broad- finned larva and Atlantic female , as well as broad-finned female ( Poecilia latipunctata ). The introduced population in the San Marcos River is also dependent on broad-finned larvae that are not naturally occurring there. Under laboratory conditions, other species of the genus were Poecilia identified as possible sexual partners: P. catemaconis , Spitzmaulkärpflinge ( P. sphenops ), Costa Rican Molly ( P. gillii ) Lanzenspitzenkärpflinge ( P. petenensis ), sulfur Molly ( P. sulphuraria ) Segelkärpflinge ( P. velifera ) and guppies ( P. reticulata ) - all of the species of the genus examined for it. With viviparous toothcarps of the genus Xiphophorus , however, no offspring could be produced.
Sex Parasitism
As a sexual parasite, the Amazon Parrot is dependent on males of other species, but at the same time the species are in competition for ecological resources. The Amazon Parrot has an advantage here, as only female animals exist, so fewer individuals are needed to produce as many offspring as the sexually reproducing competitors. On the other hand, ousting the competitors also means the end for the Amazons. For the males of the sperm-donating species, copulation with Amazon males should be disadvantageous, since they cannot pass their genes on to the next generation. In evolutionary terms, those males who can distinguish between the parasitic Amazons and the females of their own species should have an advantage. In experiments, however, it has been shown that males of the broad-fin males are more attractive to females of their own species if they have previously mated with Amazon males.
Two possible factors for the maintenance of the coexistence of parasite and host are assumed, on the one hand these are strongly fluctuating environmental conditions that prevent the species from competing with one another, on the other hand the sexual preferences of the males are supposed to regulate coexistence.
Polyploidy
In addition to the diploid amazon parrots, triploid animals are also known. Tetraploid fish also appear very rarely.
Systematics
It was possible to prove that the Amazon males originated from a hybridization event between a female Atlantic malefic and a male broad-fined malevolent about 120,000 years ago.
literature
- KP Lampert, M. Schartl: The origin and evolution of a unisexual hybrid: Poecilia formosa. In: Phil. Trans. R. Soc. B. 363, 2008. pp. 2901-2909, doi : 10.1098 / rstb.2008.0040 .
- Dieter Gentzsch: Poecilia formosa (Girard, 1859). In: Claus Schaefer, Torsten Schröer (Ed.) The large lexicon of aquaristics. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , p. 786 f.
Individual evidence
- ^ Carl L. Hubbs , Laura C. Hubbs: Apparent parthenogenesis in nature, in a form of fish of hybrid origin . In: Science 76, No. 1983, 1932. pp. 628-630.
- ↑ a b Ingo Schlupp et al .: Biogeography of the Amazon molly, Poecilia formosa. In: Journal of Biogeography 29, 2002. pp. 1-6. doi : 10.1046 / j.1365-2699.2002.00651.x
- ^ Ingo Schlupp et al .: Benefit to Male Sailfin Mollies of Mating with Heterospecific Females . In: Science 263, 1994. pp. 373-374. doi : 10.1126 / science.8278809
- ↑ Katja U. Heubel: Population ecology and sexual preferences in the mating complex of the unisexual Amazon molly Poecilia formosa (GIRARD, 1859) . Hamburg 2004. p. 104.
- ↑ Kathrin P. Lampert et al .: A Tetraploid Amazon Molly, Poecilia formosa. In: Journal of Heredity 99, 2008. pp. 223-226.
- ↑ Gabriel C. Costa, Ingo Schlupp: Placing the hybrid origin of the asexual Amazon molly (Poecilia formosa) based on historical climate data. Biological Journal of the Linnean Society, Volume 129, Issue 4, April 2020, pages 835-843, doi: 10.1093 / biolinnean / blaa010
Web links
- Amazon Parrot on Fishbase.org (English)
- Poecilia formosa inthe IUCN 2013 Red List of Threatened Species . Listed by: NatureServe, 2012. Retrieved January 11, 2014.