Monday, January 22, 2007
Seed bug primer
Feb 20, 2006. Noticed this bug on our grey-washed wood gate. I assumed it was a small milkweed bug, Lygaeus kalmii, which is common in my parts especially since I grow asclepias curassavica. The milkweed bugs, small and large, feed on milkweed mostly, and accumulate alkaloids from the plants' sap in their tissue. This makes them taste very unpleasant. Their bright coloration advertises this fact, and helps protect them from predation. Look at this photo on bugguide, though, and it's obvious my specimen is NOT the same.
Poking around for a definitive ID I came up with Neacoryphus bicrucis, the whitecrossed seed bug. There is not quite as much information on their life history, maybe these are not as common, less obnoxious, less interesting than their milkweed bug brethren. From what information I can find, whitecrossed seed bugs are said to feed on ragwort, senecio jacobaea, and other senecios. I do grow some senecios, but have yet to see their nymphs or adults feeding on those plants. Ragwort (also called stinking willie) produces alkaloids as does milkweed so it is likely the whitecrossed seed bugs are bad tasting.
Both of these bug species are members of the family Lygaeidae, the seed bugs. They both feed on plants and especially seeds. Their nymphs feed on the same plants as the adults. Both species are said to be migratory, although in Tustin's latitude it might not be obvious whether they are coming or going.