Sperm Selection After Mating :: Biology

A Bit of Background InformationWhat is pre- and post-copulatory sexual filling? From the word copulatory, meaning to wasting disease in sexual intercourse, pre-copulatory sexual extract refers to the females choice in selecting a mate before sexual intercourse takes place. Post-copulatory sexual selection occurs within the females reproductive track, and it describes the biological selection (whether due to sperm or the females biology) that results in the fertilization her eggs.Why are guppies good subjects for research in this topic? The most profound reason for using guppies in sexual selection research is because they casually participate in polyandry. This means that in nature a female guppy will mate (willingly or unwillingly) with numerous males at a time, allowing for experiments to be conducted to see which males sperm fertilizes the most eggs.Why use artificial insemination? Before the use of artificial insemination, the results of such experiments were ob scure and varied greatly. There was no way of controlling the males ejaculate sizes or thier specific sexual clash with the female guppies. By using artificial insemination techniques, these two variables can be controlled equal quantities of sperm from each male guppy can be isolated, and no sexual contact need ever take place. The increased control over these variables makes it possible to attain reliable results that are directly related to postcopulatory processes. Introduction Sexual selection is a common facet of evolutionary biology that plays a key role in the mating choices of a variety of different species. Competition amid the males sperm as well as the choice of mate by the female factor into a successful copulation.This experiment examines the precopulatory and postcopulatory demeanour of Poecilia reticulata , the guppy. Artificial insemination was used to separate the factors of sexual selection before and after sexual intercourse. Attractive males in the guppy populationdeemed attractive based on the female guppys affinity for themwere those with high levels of carotenoid coloration (orange, yellow, and red). Relative statures were also compared. The purpose of this experiment is to demonstrate, through artificial insemination, the role of postcopulatory sexual selection in a population of guppies. If guppy females are partial to specific traits, the propagation of those traits will be evident. The Methods That Were Used Prior to insemination, the behavior of the guppies involved was canvas and one adult, non-virgin female and two sexually immature fish were put in observation tanks.