What are those hordes of yellow aphids sucking juices from common milkweed (Asclepias syriaca) "reserved" for monarch butterfly caterpillars? They are Oleander Aphids (Aphis nerii) and their appearance on milkweeds reminds us that nature makes no food reservations.
This non-native aphid is best known for feeding in highly aggregated populations on members of the dogbane family (Apocynaceae); most notably on plants in the genera Asclepias (milkweeds); Cynanchum (climbing milkweed, C. laeve), Vinca, and Nerium (oleander). However, these "cosmopolitan feeders" may also be found sucking juices from over 50 hosts belonging to 16 plant families including Crassulaceae, Solanaceae, Asteraceae, Convolvulaceae, and Euphorbiaceae.