Order Homoptera: Cicadas, planthoppers, leafhoppers, whiteflies,
mealybugs, aphids, and scales
Homoptera means 'similar wing.' It is a large, diverse group composed entirely
of plant feeding insects. Like the Hemiptera, they have piercing-sucking mouthparts
and gradual metamorphosis (as seen here with the cicada nymph and adult). The
Homoptera hold their wings at an angle at rest, similar to the pitch on a gabled
roof. However, many of the Homoptera are wingless as adults (such as the mealybugs).
Some groups of Homopterans, such as the aphids and scales, have winged and wingless
As can be seen with the cicada nymph and adult above, the body
shapes are similar, however, the nymph has legs modified for digging while the
adult does not. The wing pads are visible on the nymph's back. Note how the adult
is holding its wings.
Some of the Homopterans produce honeydew, as with the mealybug
above. Using their piercing-sucking mouthparts, they remove large amounts of
plant sap. Often there is more sugar and water than what they need, so they
expell the excess. Dark sooty mold can grow on the honeydew, and the sooty mold
can be an indication of an insect infestation.
Kentucky Examples in the Order Homoptera
This is a periodical cicada. In some areas of the state these
are referred to as locusts, but they are cicadas. There are many broods of periodical
cicadas that emerge on either a 13 or 17 year cycle. Upon emerging, they cluster
on trees in wooded areas by the tens of thousands causing a nuisance with their
constant noise. The periodical cicada in Kentucky can be recognized by its red
and black coloration. Note how the wings are held like the sides of a gabled
roof and the piercing-sucking mouthparts can be seen below the head.
This is the candystriped fleahopper feeding on a grape leaf. You
can see the mouthparts inserted into the leaf. Many of the leafhoppers are vectors
of plant diseases. As they move from plant to plant probing and feeding, they
can move viruses that cause plant diseases.
This is a colony of corn leaf aphids, nymphs and adults. All of
the aphids in this picture are females that produce other females through asexual
reproduction. Asexual reproduction enables aphid colonies to increase in number
very rapidly. Many aphids have complex annual cycles switching between plant
hosts during the seasons as well as sexual and asexual reproduction. Note the
glistening honeydew produced by the aphids that is covering the leaf. Honeydew
can draw ants to these colonies and promote sooty mold growth. There are also
a few shed exoskeltons on the right. Aphids are also important vectors of plant
This is an example of an armored scale, the calico scale. For
most of their life, scale insects are sedentary, they stay in one spot feeding on
the plant underneath a protective cap. The cap protects them from many predators,
the harsh environment, and contact pesticides. The female calico scale may lay
up to 4500 eggs inside of her shell. When the eggs hatch, the active 'crawler'
stage emerges and moves about on the plant before settling down. It is this
crawler stage that is most easily controlled with contact insecticides. Once
it settles down and begins to feed, it begins to produce the protective cap.
Knowing when the crawler stage occurs in the spring is key to control of scale
These are mealybugs (not true bugs hence a one word name), a common
pest of greenhouse plants. Mealybugs are covered with a waxy coating making
it difficult for some sprays to contact the body. As with aphids, honeydew is
often associated with mealybug infestations.
This is a treehopper adult and nymphs. Note how with gradual metamorphosis
the wings buds are visible on the outside of the body. With complete metamorphosis,
wing development occurs internally in the larval stage.
Planthoppers are small, at least the ones outside of the tropics.
Many of the species are unusual in appearance. This species feeds on woody fungi.
Whiteflies, such as the greenhouse whitefly pictured above, can
be very difficult to manage. Similar to scale insects, the whitefly nymphs settle
in one spot to feed, later emerging as an adult.
Updated November 2005