Biology 342 Fall 2014
Karl Menzel and Allie Buckner
Why Is It Good To Be Eusocial?
There is a striking dichotomy in the adaptive value of individuals in a eusocial society. The reproductive members and the non or less reproductive members benefit from eusociality differently. The reproductive members have the more common relationship between partaking in eusociality and having a better lifetime reproductive fitness (LRF). The non reproductive and less reproductive members of have a more unique relationship with eusociality, their LRF is based off of the LRF of the reproductive members.
How It All Pans Out For Eusocial Species
For the reproductive member the benefit is clear. Eusociality is extremely successful, even though it is a very rare behavior. 2% of the 900,000 insect species have evolved eusocial lifestyles, but that 2% makes up half the insect biomass. Each eusocial colony is massive, and can far outnumber other herd animals. They, like all the other members of the community, only do part of the work that needs to be done but they get all of the benefit of carrying on their own genetic martial. The real question is why it is beneficial for one of the non reproductive or a less reproductive member of the society. As seen about in more detail on the evolution page, the non reproductive cast of a eusocial society may gain some benefit from the success of the reproductive class because of the relatedness of the two classes. This is true for some species that are eusocial, but for many species the reproducing members are not closely related to the non reproducing cast. In some species of eusocial animals the reproductive are related to the non reproductive cast by a distance that is much larger than family members. This would indicate that the non reproductive cast is not actually gaining all that much from the LRF of the reproductive class but it keeped in place through processes such as egg policing and genetic serality.
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