This gentleman, who was lurking in the garden the other day, is a praying mantis. Specifically, he is, I think, a European Mantis, Mantis religiosa. This is an introduced species from Europe that has become naturalized over much of the U.S. Our native California mantis is much smaller.
I say “he.” This guy can be identified as a male because he has seven abdomen segments, as opposed to the female’s five, and he has stout, long antennae, as opposed to the wispy version sported by the female.
Mantises are formidable and not very discriminating predators. Gardeners argue whether they are beneficial, but it just depends. They’ll eat what they can catch. If you have a lot of nasty gnats and mosquitoes, they’ll eat those, and welcome to them. But if those are in short supply mantises don’t mind feasting on butterflies or even an occasional small hummingbird.
The Western Tiger Swallowtail butterfly (Papilio rutulus), seen here, is a native of western North America, from the Rockies (and sometimes farther east) to the Pacific and from British Columbia to Baja California. Coastal Northern California, where I live, is one of its favorite habitats. It is a large butterfly, with a wingspan of about three to four inches (females are larger than males). It can be seen flitting about from spring through fall, and occasionally even in winter.
Art Shapiro, professor of Evolution and Ecology at the University of California, Davis, says that “The Western Tiger Swallowtail is basically a species of riparian forest, where it glides majestically back and forth along the watercourse. It has expanded into older urban neighborhoods where several of its host genera are grown as shade trees, and behaves as if the street were a watercourse. In the high country and on the Sierran east slope its usual host is Aspen.”