Bladderpod

Throughout this project, two species appear to be inextricably linked: harlequin bug and bladderpod. A general search through various references failed to turn up many specific mentions of the relationship between these organisms. It doesn’t help that the taxonomy of the plant remains a rather unsettled question. For iNaturalist users, the specific reference is currently Peritoma arborea, yet many other current references (Encyclopedia of Life, USDA Plants) use the epithet Cleome isomeris, and older publications use the binomial Isomeris arborea. The common names of the plant are also numerous, and include burro fat, spiderflower, and “skunk among plants” (referencing its unpleasant odor).

Bladderpod and its closest relatives are found over a good deal of the western US, but the range of Peritoma arborea/Cleome isomeris is restricted to Southern and Baja California and parts of western Arizona. Within that range it provides vital habitat for at least two insect species: the harlequin bug and Becker’s white butterfly (Pontia beckerii). For the butterfly, bladderpod is an important larval food. In the case of the harlequin, this insect’s entire lifecycle can take place on a single bush.

Outside of the range of bladderpod, these two insects will defer to other plants for sustenance (primarily closely related species of the mustard family), yet bladderpod appears to be especially adept at maintaining the harlequin bug in settings close to people. This may well be attributable the fact that the plant is notably wildfire resistant. So while ever more frequent fires make the SoCal landscape more biologically monotonous, Peritoma arborea (or whatever) continues to provide habitat for our most frequently observed stink bug.

Ref. Bowers, J.E., Shrubs and Trees of the Southwest Deserts (1993) Southwest Parks and Monuments Assoc.

Publicado el 01 de febrero de 2021 por jbryant