The guppies we see in the pet shops are the selectively bred descendants of the wild guppies.
True wild guppiesThe true wild guppies fish come from the rivers, streams, lakes and ponds of Barbados, Virgin Islands, Guyana Brazil, Trinidad and Tobago, Venezuela, Mexico and the State of Florida.
Each of the water body in isolation has developed differing phenotypes and gene pools.
When in floods there is remix of the populations and diversity is strengthened.
They show great diversity in phenotype, easily visible in the males of these species in the form of great range of colours and patterns.
The access to these populations is limited to collectors and the people living in these regions.
Due to regulations and availability, it is hard to get them and they are also priced high.
Descendants of wild guppiesThe 'wild guppies' sold in the pet shops and breeding facilities carry the tag of doubt.
At most they could be the early descendant generations of the wild varieties.
They are also priced high and breeding facilities may buy them to improve the genetic vigour of the brood stock.
Founder effect in captive-bred wild guppies fishIn a new population established by a small number of individuals from a larger population, the genetic variation is lost and this effect is termed as Founder effect in population genetics.
As they are not the descendants of a very large population, when brought to the breeding facility and bred in captivity, in 4-5 generations they lose the diversity and exhibit similar phenotype.
Genetic drift in captive-bred wild guppiesAllelic drift or genetic drift is the change in the relative frequency in which allele (genetic variant) occurs due to chance and random sampling.
The effect of genetic drift is larger in a small population of these fish and genetic variation is slowly lost.
In a larger population of these fish genetic equilibrium is maintained.
Further in the protected environment there is feeble natural selection and the least fit also may survive and the identity of the original phenotype is lost.
Negative frequency dependent selection in wild guppiesNegative frequency dependent selection in these wild fish is the result of interaction between them and their predators and also among the phenotypes.
It is found that rare brightly coloured and spotted male fish are attractive to the females and get better and more mating chances.
It is also found that orange spotted males are preferred by the females.
For the predators of this fish, common colouration seem to be a known attractive prey and the rare coloured males have less chances of being eaten.
'Wild guppies' away from their native homelandsThese guppies fish varieties have been introduced in to many countries in the world for the purpose of controlling mosquitoes.
These guppies fish have thrived well in the new environments creating diverse phenotypes and genotypes.
These introduced species of fish have become pests in many a host country affecting its native fauna and flora.
Ornamental fish breeding facilities, especially in Asia have released unwanted males and females of these ornamental guppies fish into drains and waterways and these have got established well.