Friday, November 30, 2007
Milkweed Community #2
I noticed this large milkweed bug (Oncopeltus fasciatus) on top of a milkweed plant about two weeks ago. This is an adult female and so far she is the only one of her species in my milkweed patch. Probably she is overwintering, as there has been no sign of a mate or any egg laying, and it's getting a bit cold. These bugs feed on milkweed seeds and are toxic to those who might eat them, thus the bold warning coloration. This species is new to my milkweed this year, and it seems that the quantity of milkweed plants I have now has crossed a threshold of attractiveness to insects seeking a reliable source of asclepias. But what is that threshold and how do the bugs determine it has been crossed?