Swordtail fish (Poeciliidae: genus Xiphophorus) are a paradigmatic case of sexual selection by sensory exploitation. Female preference for males with a. North and Central America: Rio Nantla, Veracruz in Mexico to northwestern Honduras. Africa: Feral populations reported from Natal and eastern Transvaal as. Xiphophorus hellerii was described by Heckel . Confusion exists on the designation of the species name as either hellerii or s: Xiphophorus hellerii.
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In the aquarium it is unfussy and will accept just about anything offered. Offer a balanced diet comprising good quality dried products along with small live and frozen foods such as Daphnia, Artemia and chironomid xiphophorus helleri bloodworm. In some ornamental strains the upper xiphophorus helleri lobe or other fins may also be extended, however, including in females.
Green swordtail - Wikipedia
Some of these forms are also the result of artificial hybridisation with other members of the genus, particularly X. See the images xiphophorus helleri to this profile for some by no means exhaustive examples.
The genus is split into three main phylogeographic clades: The relationships within these groups have also xiphophorus helleri studied in depth.
The perceptual mechanisms underlying female mate choice have not been identified, complicating efforts to understand the selection pressures acting on ornament design.
Xiphophorus helleri consider two alternative models of receiver behavior, xiphophorus helleri consistent with previous results.
Females could respond either to specific characteristics of the sword or to more general cues, such as the apparent size of potential mates.
We showed female swordtails a series of computer-altered video sequences depicting a courting male. Footage of an intact male was preferred strongly to otherwise identical sequences in xiphophorus helleri portions of the sword had been xiphophorus helleri selectively, but a disembodied courting sword was less attractive than an intact male.
There was no difference between responses to an isolated sword xiphophorus helleri to a swordless male of comparable length, or between an isolated sword and a homogenous background. Female preference for a sworded male was abolished by enlarging the image of a xiphophorus helleri male to compensate for the reduction in length caused by removing the ornament.
This pattern of results is consistent with mate choice being mediated by a general preference for large males rather than by specific characters. Similar processes may account for the evolution of exaggerated traits in other systems.
The resulting ornaments are relatively stereotyped, xiphophorus helleri the same distinguishing features within a species.
The specific xiphophorus helleri of ornaments that have evolved in response to ancestral biases suggests two possible accounts of their origin. Females may exercise a specific, narrowly defined, preference for a particular stimulus.
Sexual selection would then substantially constrain the design of the male ornament. Alternatively, females may have a predilection for broad classes of stimuli. If xiphophorus helleri scenario was true, a wide variety of phenotypes might increase male mating xiphophorus helleri.
The specific form of an ornament would then be constrained by factors other than mate choice, such as intrasexual xiphophorus helleri, natural selection, and evolutionary history.
Male swordtails Xiphophorus were cited by Darwin 6 as an example of extreme sexual ornamentation. Males of xiphophorus helleri sister group Priapella are also swordless.
Females from two platy species, X. Invasive Species[ edit ] X.
It has caused ecological damage because of its ability to rapidly reproduce xiphophorus helleri high numbers. Significant populations have also established themselves along the east coast of Australia.
- Xiphophorus hellerii, Green swordtail : aquarium
- Xiphophorus hellerii – Green Swordtail (Xiphophorus helleri, Xiphophorus guntheri) — Seriously Fish
- Xiphophorus hellerii
- Human uses
- Green Swordtail
- Xiphophorus hellerii
It is named after Karl Bartholomaeus Hellerwho collected the type specimen.