I love alphabet books since they must be very challenging to write, especially if you are attempting to write one that isn't cookie-cutter like the rest for your particular subject. And as a result I take it very seriously when I look at these types of books.
For me Bug Alphabet is one that I am getting used to while it has its moments of charm. The book clearly doesn't struggle to be so scientific that it goes over young readers' heads as shown by the wrongly used term "bug" in its title but instead as implied by the same word tries to reach for the easiest to grasp concept for the same audience.
Readers will find each spread is dedicated to one letter with the left being dedicated as a sort of "header page". On this page readers will find both a capital and lowercase letter and what it stands for alphabetic-wise in this book. On the opposite page is an anthropomorphic portrayal of the focal insect(s) and a small fact provided in easy text.
Keeping with the preschooler-friendly vibe, though, means the insects are mostly kept to a basic catchall family such as ant, grasshopper, etc. The only exception seems to be for some of the much harder letters, the author falls back upon the butterflies and moths to use as individual species. But to offset that the book is a mixture of some much more well-known insects combined with those that may be lesser-known.
Readers are presented with as mentioned previously anthropomorphic, cartoonish insects, which I wasn't a fan of but it does make them easier for young children to grasp as befits this book's focal.
But what I really like is in the back are included a list of colored photographs so you can see the actual insect that made it into the book. Furthermore there is a Spot the Character game followed in the back and an alphabetic color chart as each letter has its own colors, of which there are a few I have never heard of such as queen pink or zomp.
Given to its creativities, bright colors and informative position I really would recommend this book for young readers.