In  her book Wicked Bugs, a darkly comical look at the sinister side of man’s relationship with the natural world, author Amy Stewart tracks down more than 100 of the worst entomological foes – creatures that infest, infect, and generally wreak havoc on human affairs. Ms. Stewart is the bestselling author of five books on the perils and pleasures of the natural world, including Wicked Plants. Her essays and commentaries have appeared on NPR, in the New York Times, and in Fine Gardening, where she is a contributing editor. Stewart is the recipient of a National Endowment for the Arts fellowship and the American Horticultural Society’s 2010 Book Award. She lives in Eureka, California, where she and her husband own an antiquarian bookstore.  Amy Stewart will make an appearance at Porter Square Books in the Porter Square Shopping Center, 25 White Street, Cambridge, this Friday, October 21, beginning at 7 pm.  If you plan to attend this free event, call 617-491-2220, or email ellen@portersquarebooks.com.