Question

Jack volunteers himself and his hunters to keep the fire going: "Ralph, I'll split up the choir—my hunters, that is—into groups, and we'll be responsible for keeping the fire going." In some ways, this can be understood as an example of Jack’s contributing to the larger group. However, knowing that Jack is something of a rival to Ralph and how he treats Piggy, how else might Jack's volunteering of his hunters be interpreted?

Answer 1

The other way that Jack's volunteering of his hunters be interpreted is :
A vie for power.
If he is the leader of the hunters, and the hunters provide food, than he has the power over those  who want to eat something other than fruits

hope this helps