EPOW - Ecology Picture of the Week

Red and Black on Yellow

Whitecrossed Seed Bug (Neacoryphus bicrucis), Family Lygaeidae
on Deltoid Balsamroot (Balsamorhiza deltoidea), Family Asteraceae
Columbia River Gorge, Oregon, USA

Explanation:  What a fine display of spring colors.  Halfway up the Columbia River Gorge that separates Washington and Oregon in western U.S. occurs a landscape of open oak woodland and wildflower meadows.  A common denizen is the whitecrossed seed bug, noted for its striking white-edged red and black wings forming an X over the body.  
 

Whitecrossed seed bugs belong to the seed bug family (naturally), which is the second largest bug family in North America.  

Adults of whitecrossed seed bugs hibernate as daylight grows shorter in the fall.  They may do this to ensure synchrony of emergence and mating in the spring (Solbreck 1979).

Whitecrossed seed bugs are commonly associated with plants called groundsel (Senecio triangularis; Haggard & Haggard 2006) or with ragwort (S. anonymus) although I have also commonly seen them on this brilliant plant, balsamroot.  The bugs congregate where their host plants occur in dense patches, and the males defend small territories on the host plants, which is why you do not see groups of them on any individual plant.  

Two species of balsamroot occur in Oregon, deltoid balsamroot (this species, Balsamorhiza deltoidea) and the arrowleaf balsam root (B. sagittata) which has leaves that are more silver-gray and that are covered with fine hairs. Balsamroot leaves are eaten by deer and elk in the spring.  Local indigenous people ate the young stems, seeds, and roots, and also made medicine from the roots.  

And the flowers make for a striking background for whitecrossed seed bugs.
  

Information:
     Haggard, P., and J. Haggard. 2006. Insects of the Pacific Northwest. Timber Press, Portland, Oregon. 295 pp.
     Mathews, D. 1988. Cascade-Olympic natural history. Raven Editions and Portland Audubon Society, Portland, Oregon. 625 pp.
     McLain, D.K.  1984.  Host plant density and territorial behavior of the seed bug, Neacoryphus bicrucis (Hemiptera: Lygaeidae.  Behavioral Ecology and Sociobiology 14(3):181-187.
     Solbreck, C.  1979.  Induction of diapause in a migratory seed bug, Neacoryphus bicrucis (Say) (Heteroptera: Lygaeidae).  Oecologia 43(1):41-49.