Aphids are still plentiful on milkweed plants. These yellow ones are called oleander aphids, and also, more apt in this situation, milkweed aphids. There are some winged ones present here, and on some stems, the larvae of Asian ladybeetles, preying on them. Winged aphids are often produced when conditions become crowded and the need arises to disperse some of the colony to better sites. This small stand of milkweed was thick with aphids, and further down the stem they were clustered so tightly the stem looked yellow.