Insect Identification on milkweed
I apologize, but I can’t add anything definitive, beyond what Jean has already written. It is surely a caterpillar - but too young to ID with any degree of confidence. Since insects in milkweed are fairly limited, i’m Drawn to milkweed tussock moth or monarch butterfly. But Multnomah County seems too far north for monarchs, and the egg mass doesn’t look right (monarch eggs are not usually laid in a mass, but are instead laid singly). The Tussock moth range is too far west, but the egg mass looks correct. I would be interested to see a photo of the caterpillars at a later stage, is that is att possible - perhaps in a week? Keep in mind that in a week’s time, yellowjackets might capture and kill the caterpillars, or something else might carry them away. But, if at all possible to have a look at older instars, I would love to have a second crack at an ID.