Paul R. Ehrlich & Ilkka Hanski 
On the Wings of Checkerspots [PDF ebook] 
A Model System for Population Biology

Hanski, a leading thinker in metapopulation ecology, studies checkerspot butterfly populations in Finland. Ehrlich, one of the leading ecologists and conservation biologist, investigates checkerspot butterfly populations in California. This book reports on and synthsizes the major long-term research of both workers’ careers on the population biology of checkerspot butterflies.