Question

Suppose that a female Belding’s ground squirrel has four offspring: three of them survive because of her parental care, but the fourth survives without her care. Further, she saves the lives of two nieces through alarm-calling. Calculate her “inclusive fitness”? Define direct and indirect fitness in your complete answer.

Answer 1

An individual's "inclusive fitness" which is the sum of an individual's direct fitness,the number of offspring produced and indirect fitness,the number of relatives(niece and nephews)produced multiplied by the degree of relatedness of those individuals.

Here in this question Female Belding's grounds squirrel has four offspring,three of them survive so this number include in direct fitness and she saves the lives of two nieces through alarm-calling,this include in indirect fitness.

Direct fitness - N * r = 3*1/2

Indirect fitness - 2*1/4 =1/2

Inclusive fitness is 3/2 + 1/2 = 2

here r is the coefficient of relatedness.