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| Family Cicadidae
(Cicadas) Description
Some cicadas are among the biggest of all insects and most are quite large. Although the average body length is 1 to 2 inches, the Malaysian empress cicada (Pomponia imperatoria) has a wingspan of 8 inches. Distribution More than 1,500 species of cicada are known throughout the world. They are mainly tropical, extending into the temperate regions in small numbers. A few species occur in southern Europe, and about 75 occur in North America.
Eggs are laid in slits in the twigs of trees. Nymphs fall to the ground after hatching several weeks later, and then dig down with their broad, powerful front legs and disappear underground. They will spend the majority of their lives in a burrows that may anywhere from several inches to a few feet underground, depending on the nymphal stage and nature of the soil. The duration of the nymphal stage varies by species. Among the longest-living of all insects, many cicada nymphs take 2 to 5 years to develop into an adult, while still others spend 17 years in the nymphal stage. When ready to mature, the nymph digs its way up to the surface and climbs the nearest tree, where it rests before shedding its skin and emerging as an adult cicada. Despite their long lives as nymphs, however, adult cicadas only live 6 to 10 weeks, time they spend eating and mating. Diet Cicadas belong to an order of insects with piercing and sucking mouthparts. Adults feed on the sap of plant stems and succulent shoots, while nymphs extract sap from roots. The specific types of plants fed upon varies by species and location. Habits and Behaviors Adult cicadas spend most of their time sitting high up on the trunks of trees, or among the branches and foliage. When approached they will usually fly off quickly. Their flight is fast and powerful.
The singing apparatus consists of a pair of membranes at the base of the abdomen, each surrounded and held by a stiffly elastic ring. The membrane is convex when relaxed, but a muscle attached to it can pull it down and allow it to pop back. The membranes, known as tymbals, oscillate at a rate of 100 to 500 times per second. Other muscles attached to elastic ring distort the ring's shape, affecting the volume and quality of the sound produced. The whole apparatus is enclosed in a pair of resonating chambers which amplify the sound and vary it by opening and closing.
Right: How the pulsing tymbal muscle repeatedly distorts the abdominal wall and allows it to snap back producing the basic sound. Scientific Classification phylum Arthropoda Questions or comments about this page?
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Cicadas have a broad, flattened body and two
pairs of large wings with characteristic pattern of
veins. The longitudinal veins do not extend to the edge
of the wing but stop short of it, leaving a narrow,
uninterrupted margin along the outer border of each wing.
The wings are usually transparent, but those of some
species are colored and patterned, and when at rest they
are folded over the body like a roof.
Life Cycle
All
species of cicada "sing," and every species has
its own distinct song. Although singing is exclusive to
males in most species, there are a few species in which
the females also sing. Both sexes have hearing organs,
and all cicadas can recognize the song of their species.
Some cicadas sing during the day, others only at dusk or
dawn; some sing intermittently, while others may sing for
extended periods of time. The purpose of the cicada's
song is probably to call the local population a species
together for mating purposes.
Left: 1) Cicade underside: sound-boxes are
covered by a protective plate (operculum). 2)
The cicada's muscular attachment, showing the tymbal's
position in the air cavity which helps amplify the sound.
3) A cross-section through the thorax shows the powerful
muscles attached to the tymbal sound-boxes, which have
concave inner surfaces.
