Aphidoidea

Aphidoidea are distinguished from other Sternorrhyncha by the presence of cornicles (siphunculi), paired tubular structures on the posterior abdomen that excrete defensive secretions. They typically have soft, pear-shaped bodies with long antennae and reduced wing venation when alate forms are present. Unlike psyllids or whiteflies, aphids lack the powdery wax covering and have distinctive tarsi with two claws.

Found in virtually all terrestrial environments where host plants occur, from arctic tundra to tropical forests. Many species are specific to particular host plant taxa, while others are polyphagous. Agricultural and horticultural environments often support high densities due to abundant, nutrient-rich host plants.

Cosmopolitan distribution with species documented on every continent except Antarctica. Highest diversity in temperate regions of the Northern Hemisphere.

Activity patterns vary by climate and life cycle strategy. In temperate regions, many species are active spring through autumn, with overwintering eggs or dormant stages during winter. In tropical and subtropical regions, continuous reproduction occurs year-round. Some species exhibit complex host alternation with distinct spring and summer host plants.

Phloem-feeding specialists, extracting plant sap through piercing-sucking mouthparts. Some species are restricted to single host plant genera or families, while others feed on diverse plant taxa.

Complex polymorphic life cycles characteristic of many species, involving multiple morphological forms including fundatrices, virginoparae, sexuparae, males, and oviparous females. Parthenogenetic viviparity dominates during favorable conditions, with sexual reproduction and egg production typically occurring in autumn. Some species exhibit host alternation between a primary woody host for sexual reproduction and secondary herbaceous hosts for parthenogenetic generations.

Form dense colonies on host plants. When disturbed, excrete cornicle secretions containing alarm pheromones that trigger dispersal in nearby colony members. Many species are attended by ants that harvest honeydew and provide protection from predators and parasitoids. Winged forms produced in response to crowding or declining host quality, enabling dispersal to new plants.

Major herbivores in terrestrial ecosystems, transferring significant plant biomass to higher trophic levels. Serve as primary prey for diverse predators including lady beetles (Coccinellidae), lacewings (Chrysopidae), hoverflies (Syrphidae), and parasitoid wasps. Honeydew production supports complex food webs including ants, fungi, and microorganisms. Some species are vectors of plant pathogens, particularly viruses.

Among the most economically significant agricultural pests globally, causing direct damage through feeding and indirect damage as vectors of plant viruses. Major pests of cereals, vegetables, fruits, and ornamental plants. Subject to extensive biological control programs using predators, parasitoids, and entomopathogenic fungi. Some species produce commercially valuable products including shellac and carmine dye.

• PsylloideaSimilar small sap-sucking Hemiptera, but psyllids have more robust bodies, hold wings roof-like over body, and lack cornicles; nymphs are often flattened and sessile with waxy secretions.
• CoccoideaBoth are Sternorrhyncha with reduced wing venation and plant-feeding habits, but scale insects are typically immobile as adults, lack visible antennae and legs in many forms, and possess protective scale coverings rather than cornicles.
• AleyrodoideaWhiteflies share phloem-feeding habit and powdery wax secretions, but adults have wings held tent-like over body, lack cornicles, and have different wing venation patterns.

• Hemiptera
• Sternorrhyncha
• phloem-feeding
• parthenogenesis
• agricultural pest
• cornicles
• honeydew
• ant mutualism
• vector
• biological control

• BugGuide
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• ID Challenge #16 | Beetles In The Bush
• Aphidoidea of Åland, SW Finland
• "About the ""parasite-host"" relationship system of aphids (homoptera, aphidoidea)"
• Cinara (Hemiptera: Aphidoidea) species distributed in Turkey and their host plants Türkiye'de dağılım gösteren Cinara (Hemiptera: Aphidoidea) türleri ve konak bitkileri
• Aphids, sex, chromosomes and molecular biology (Hemiptera: Aphidoidea)
• Description of sexuales of Periphyllus singeri (Börner) (Hemiptera, Aphidoidea: Chaitophorinae)
• The sexuales of Thelaxes suberi (Hemiptera, Aphidoidea: Thelaxinae)