Thanks for submitting this amusing passage. I laughed aloud at a source of more ego battles and power posturing than is evident during the entire Serengeti rutting season.
The best image I can think of (at the moment) is the one used by the author: male animals competing for status during mating season. Yes, it means power struggle, but the author here has chosen to focus not on the struggle in terms of high-level mental strategizing, but on the more unconscious or primitive level of animals struggling for primacy.
a dotted line
Here, a dotted line refers to the lines used to indicate the complex hierarchy of the managers and others at the executive level of a company.
The way the 'dotted lines' connect individuals indicates who is subordinate to whom.
The author is saying that, while a diagram of the power structure within a company may appear to be a dry and objective representation, to those behind the scenes it tells a tale of fierce and desperate battling for dominance.
I hope this is helpful,
Student or Learner