Aphis nerii

Definition

A bright yellow aphid species in the family Aphididae, obligately associated with milkweeds (Asclepias spp.) and oleander (Nerium oleander). Reproduces parthenogenetically year-round in warm climates, producing live young without mating. The bright aposematic coloration advertises sequestration of cardiac glycosides from host plants, rendering adults and nymphs unpalatable to predators.

Etymology

Aphis from Greek aphis, aphid; nerii from Nerium, the oleander genus

Example

Aphis nerii colonies on milkweed stems can reach densities of hundreds per shoot, with alate morphs produced for dispersal when crowding triggers wing development.

Synonyms

• oleander aphid
• milkweed aphid
• nerium aphid

Related Terms

• Aphididae
• Parthenogenesis
• host-plant specialization
• cardiac glycoside sequestration
• alate morph
• Holocyclic life cycle

Usage Notes

Often treated as an obligate specialist on Apocynaceae, though occasional records on other families occur. The bright yellow color with black legs and cornicles distinguishes it from other yellow aphids; do not confuse with Aphis asclepiadis, a less common milkweed specialist. Populations are anholocyclic (no sexual phase) in most of their global range, complicating classical biological control efforts.