Aphids are a type of small, soft-bodied insects. They have a wingless, pear-shaped body. When the aphid population increases, they develop wings to travel to new habitats. Since aphids are plant-specific, they can be identified based on the type of plants they feed on. Some of the common types of aphids are potato aphid, cabbage aphid, green peach aphid, melon aphid, and wooly apple aphid. The color of the aphid’s body varies with the species, but they are mainly black, green or yellow in color.
Key Areas Covered
Key Terms: Aphids, Cornicles, Honeydew, Reproduction, Sucking Mouthparts, True Bugs
What are Aphids
Aphids are a type of insects that belong to the group called true bugs. They are also known as plant lice or greenflies. Approximately, 1300 aphid species are found worldwide. Out of that, 80 species are pests on crop plants. They have specialized mouthparts to suck fluids from plants. They infest cultivations, gardens as well as landscapes. In addition to infestation, aphids serve as vectors for plant viruses. Aphids produce a sugar-rich sticky substance known as honeydew. They release honeydew from the terminations of the alimentary canal. Some ants have a mutualistic relationship with aphids to milk the honeydew. Reproduction of aphids mainly occurs through parthenogenesis, without the involvement of a male. The reproductive mode of aphids is viviparity since they give birth to the live young. Ladybugs, big-eyed bugs, pirate bugs, lacewings, stinging wasps, and crab spiders are natural enemies of aphids. A pea aphid is shown in figure 1.
How to Identify Aphids
Characteristics of aphids that helps in the identification of aphids are listed below.
- Small body size (1/8 inches)
- Pear-shaped, soft body
- Most aphids wingless. They generate wings in large population numbers.
- The color of an aphid varies with its species. Colors can be yellow-green-black.
- Aphids are plant-specific.
- Aphids have a soft body, small eyes, and large antennas.
- Aphids have sucking mouthparts.
- Aphids have three pairs of legs.
- The needle-like mouthparts of aphids are adapted to suck.
- Aphids suck plant sap, which contains lesser amounts of proteins.
- In order to fulfill protein requirements of the body, aphids have to suck more sap, and the excess fluid is eliminated from the body in the form of honeydew.
- Aphids have tube-shaped structures called cornicles at the end of the body.
- Aphids undergo incomplete metamorphosis.
Aphids are a type of small, true bugs that vary in color. They are plant-specific. They have sucking mouthparts, and they produce honeydew. Aphids have cornicles at the end of the body.
1. “What Are Aphids | Aphid Insect Facts, Habitat & Control Options.” Safer® Brand, Available here.
1. “Acyrthosiphon pisum (pea aphid)-PLoS” By Shipher Wu (photograph) and Gee-way Lin (aphid provision), National Taiwan University – PLoS Biology, February 2010 direct link to the image description (CC BY 2.5) via Commons Wikimedia