Aphididae

Aphididae is the largest family of aphids, a group of small sap-sucking insects in the order Hemiptera. Within the superfamily Aphidoidea, Aphididae contains the majority of described aphid species. They are distributed worldwide and occupy a wide range of plant hosts, from crops to ornamentals and wild plants.

Aphids in this family are typically soft-bodied and small, often less than a few millimeters in length. Adults can be wingless or winged, and many live in colonies on the undersides of leaves or young shoots. They feed on plant phloem using piercing-sucking mouthparts. A common feature is the presence of cornicles (siphunculi) on the abdomen that secrete defensive fluids.

Life cycles in Aphididae are diverse but many species exhibit complex seasonal patterns. In favorable conditions, populations reproduce asexually by parthenogenesis, producing live young and allowing rapid colony growth. As conditions change, some species produce winged forms that disperse to new hosts. In temperate regions, many also have a sexual phase that generates eggs on a primary host to overwinter, a pattern known as holocyclic life history; others reproduce only by parthenogenesis year-round, known as anholocyclic.

Ecology and economic importance: Aphids excrete honeydew, which can foster secondary microbial growth, and ants may cultivate them for this sugar source. They are important agricultural pests, feeding on a wide range of crops and ornamentals. Aphids are also vectors for plant viruses, transmitting luteoviruses, potyviruses, and other pathogens in persistent or semi-persistent modes, contributing to disease outbreaks.

Management often relies on natural enemies such as predatory insects and parasitoid wasps, along with cultural practices and selective controls to minimize crop damage and virus spread.