Subject: What are these two insects?
Geographic location of the bug: Ben Lomond, CA. Santa Cruz County, CA. Redwood forest.
Date: 06/20/2019
Time: 02:20 PM EDT
Your letter to the bugman: Crowd sourcing all entomologists! I found these two creatures on my backdoor yesterday. I am guessing they are either grasshopper or katydid nymphs. If they are the same species, they show sexual dimorphism. The bottom one was about 2-2.5 inches long (minus antennae). I also assume that nymphs do not mate . . . so are these two just hanging out together? Any clarifications welcome.
How you want your letter signed: Carla
Dear Carla,
What an exciting submission to our site you have submitted. These are not nymphs, and though there is no actual coupling happening, your images document a male (smaller and on top) and female Timema engaging in pre- or post-mating activity. Timemas are related to Walkingsticks, not Orthopterans, and according to BugGuide the habitat is: “On foliage, twigs, or branches of host shrubs or trees…or on the ground near base of host or other plants, where they may retreat during the day or drop upon disturbance. Sometimes also found sheltering under stones. Host plants mostly associated with chaparral; some with woodlands or forest (e.g. douglas fir, redwood). Green morphs tend to rest on leaves; brown to gray morphs on stems, branches or ground. Unstriped morphs are usually associated with broad-leaved host plants (e.g. oaks, ceanothus, manzanita, etc.). Striped morphs are usually associated with host plants having needle-like leaves (e.g. chamise, douglas fir, redwood, etc.). Coloration, stripes, and other markings serve as camouflage, and are adaptations driven by selection pressure due to predation by visually-oriented birds and lizards.” BugGuide also has a map showing the ranges of some of the 21 recognized species, but BugGuide also notes: “dependable species ID requires study of the shape of externally visible structures of the terminalia, especially of the male (for non-parthenogenetic spp.)…in conjunction with location, host plant, color and markings” but that is beyond our area of expertise. Based on the map, our best guess is that your species is Timema californicum, and BugGuide does indicate: “T. californicum has records north of San Francisco Bay in Marin Co.” Of that species, BugGuide notes: “Recorded host plants: manzanita (Arctostaphylos spp.), ceanothus (Ceanothus spp.), oak (Quercus spp.), mountain mahogony (Cercocarpus spp.), toyon (Heteromeles arbutifolia).” If we miscalculated your location, please let us know. In closing, BugGuide also notes: “NEWS ITEM! (3/29/18): The Timema Discovery Project is an important new initiative aiming to harness as many people as possible to collect much needed data for advancing our understanding of Timema…please visit the web site, spread the word, and participate!” Thanks again for submitting this exciting posting.
I’ve wanted to see a timema in the wild for decades. So far no joy. The California dogface butterfly is the state insect of California, but I would have opted for T. californicum if it had been my choice, I’m aware that timemas also occur in Washington, Oregon, and Arizona, but I think of it as an honorary Californian endemic.