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Aphididae is a very large insect family in the aphid superfamily (Aphidoidea), of the order Hemiptera. There are several thousand species in this family, many of which are well known for being serious plant pests. They are also the family of insects containing most plant virus vectors (around 200 known) with the green peach aphid (Myzus persicae) being one of the most prevalent and indiscriminate carriers.

Evolution

Aphids originated in the late Cretaceous about 100 million years ago, but the Aphidinae which comprises about half of the 4700 described species and genera of aphids alive today come from their most recent radiation which occurred in the late Tertiary less than 10 million years ago.^[1][2]

Characteristics

Members of the Aphididae are soft-bodied, pear-shaped insects called aphids, as are other members of the super-family Aphidoidea. Most of them have a pair of little tubes, called cornicles, projecting from the posterior of the abdomen. Wings are not always present; winged morphs are called "alates", while wingless morphs are known as "apterous". The forewings of Aphididae alates are dotted with 4 to 6 veins below the darkened stigma. They all have very small eyes, sucking mouthparts and fairly long antennae.

These insects are very small (a few millimeters in length), so small that they can be transported by wind through fairly long distances. They are often green, but might be red or brown as well. They move quite slowly and cannot jump or hop.

Aphids excrete a sugary liquid called honeydew, because the plant sap from which they feed contains excess carbohydrates relative to its low protein content. To satisfy their protein needs, they absorb large amounts of sap and excrete the excess carbohydrates. Honeydew is used as food by ants, honeybees and many other insects. A common misconception is that honeydew is secreted through the cornicles.

Genera

See also

References