James and Nunnallee introduce us to the fascinating world of butterfly life histories by first reviewing the four life stages – eggs, larvae, pupae, and adults. We learn that newly emerged larvae are first instar. As larvae grow and molt – typically five times – each newly molted larva is referred to as a second or third instar, and so on.

The authors proclaim “Butterflies are inextricably linked to plants…” and their introduction illuminates the many ways in which this is true. They explain that most female butterflies search for just the right plant on which to oviposit; they chemically test plants by drumming their legs on leaves, stems, and flowers. The chosen plant provides immediate nourishment for diminutive caterpillars emerging from tiny eggs.

Some plant/butterfly relationships may amaze you. For instance, when larvae sense that their host plant verges on senescing, they respond by suspending their own development, or entering “diapause”. I was surprised to learn that some plants respond to caterpillar attack by issuing chemical distress signals to attract bugs that prey on butterfly larvae.

The most impressive feature of this book is the species accounts. Grouped into families, each species is given a two-page spread where James and Nunnallee describe – and show photographs of – every single stage of a butterfly’s life, from egg to larva to pupa to adult. Trumping that, they provide not just one photograph of each species’ larva, but photographs of almost every instar of every species. While this may leave readers wondering about the authors’ sanity, anyone using this book would readily concede that caterpillar ID would be impossible without these wonderful photographs.

It’s easy to break into using this book. Suppose you notice a smooth green caterpillar with fake eye spots munching on chokecherry. The authors shortened your search with three “Quick Photo Guides”. These two-page spreads show representative assortments of eggs, larvae, and pupae, with species and group names captioned. There you can quickly recognize to what group your caterpillar belongs, then thumb through that group to home in on your larva. Without much effort you’ll know that you’re in close contact with a Two- tailed Swallowtail, Papilio multicaudata, the largest butterfly in Washington.

You’ll also learn that earlier instars of Two-tailed Swallowtails look amazingly like bird droppings, leading you to re-examine some of those brown and white lumps littering your chokecherry’s leaves. And you’ll learn that your larva is likely to pupate to while away winter, then eclose and fly next spring.

This book is uniquely suited to guide plant-lovers in understanding and appreciating butterflies in all their life stages. If you are just beginning to identify butterflies, this book alone is not ideal for you; species accounts omit adult butterfly identification details. But Life Histories of Cascadia Butterflies will enormously expand your understanding of all butterfly life stages and their relationships with plants.

At 447 pages, it’s a bit oversized for use in the field. That won’t be stopping me; I can’t wait to go out with this book in my backpack.