Hermit crab metaphor for writing scientific introduction

I've been taking a writing workshop for the past few weeks.  The instructor taught us something really cool.  The introduction to a scientific paper can be thought of as a hermit crab finding its shell.  Swales and Feak [1] call this "moves in introductions."

1. Establish a research territory.
2. Find a niche.
3. Occupy the niche.

I thought this metaphor was really cute and colorful.  I'll think of hermit crabs the next time I read or write an introduction.

[1] Swales, John M. and Christine B. Feak. Academic Writing for Graduate Students, The University of Michigan Press (2004)