Question

Scientists studying scrub jays found that “helpers” often assist mated pairs of birds by gathering food for their offspring.

(A) Propose a hypothesis to explain what advantage there might be for the helpers to engage in this behavior instead of seeking their own territories and mates.

(B) Explain how you would test your hypothesis. If it is correct, what results would you expect your tests to yield.

Short answer

1. “Helpers” do not seek their territories because it cannot assure their safety or survival. They assist the mated pairs because it gives them food and shelter.

2. The hypothesis can be tested by observing two different populations of scrub jays – a large population with helper birds and a small population that only includes mated pairs. If the hypothesis is true, the larger population with helper birds shows a higher percentage of offspring survival. This is because there is greater availability of food in a large population due to the serving of helpers.

Step-by-step solution

Cooperative breeding

The rearing of young ones in certain species of birds occurs by the care of more than two birds,and such a breeding mechanism is called cooperative breeding.

In cooperative breeding, a helper bird is associated with a mated bird and helps to gather food. The helpers or mature non-breeders are often denoted as “helpers at the nest.” Shared paternity or maternity is seen in cooperative breeding.

Explanation of part ‘(A)’

A hypothesis that explains the advantage would be getting safety, shelter and food from the mated species.The mature non-breeding birds do not seek mates or shelter because it does not provide security to them.

Therefore, they live with a mated species and help them collect the food. Mated birds offer the helpers space in their nest.

Kin selection is seen in the species of scrub jays due to the selfless behavior of helpers. It increases the reproductive success of genetically similar species of helpers. Selfless behavior also brings advantages to them in terms of shelter.

Explanation of part ‘(B)’

The hypothesis that deals with the advantages that helpers get from living with mated species can be tested by studying two different populations of scrub jays – a large population that includes mates and helper birds and a population with only mated birds.

Due to the increased competition in the population of scrub jays,paired birds with helpers show more success rate in reproduction and rearing of young ones.This is because the female gives constant attention to incubation, and the male and helper gather the food.

Cooperative breeding appears to be adaptive behavior developed by birds for reproductive success.