Cicadas 2007 in Illinois, Every 17 Years

Cicada on a post in Orland Park, Illinois on May 27, 2007 [Approx. MAP/SAT].

A cicada is an insect of the order Hemiptera, suborder Auchenorrhyncha, in the superfamily Cicadoidea, with big eyes wide apart on the head and usually transparent, well-veined wings. There are approximately 2,500 species of cicada around the globe, and many remain unclassified. Cicadas live in temperate to tropical climates where they are one of the most widely recognized of all insects, mainly due to their large size and remarkable (and often inescapable) acoustic talents. Cicadas are sometimes called “locusts”, although they are unrelated to true locusts, which are a kind of grasshopper. Cicadas are related to leafhoppers and spittlebugs.

Cicadas do not bite or sting, are benign to humans, and are not considered a pest. Many people around the world regularly complement their standard diet with cicadas: the female is prized for eating as it is meatier. Cicadas have been eaten (or are still eaten) in Ancient Greece, China, Malaysia, Burma, Australia, North and South America and the Congo.

Cicada are employed in the traditional medicines of China and Japan for hearing-related matters, poignant considering that they are known for the mating song the males of the species make. The word cicada is a direct derivation of the Latin cicada; in Greek they are referred to as tzitzikia or tettix.

Cicadas are arranged into two families: Tettigarctidae (treated elsewhere) and Cicadidae. There are two extant species of Tettigarctidae, one in southern Australia, and the other in Tasmania. The family Cicadidae is subdivided into the subfamilies Tettigadinae, Cicadinae and Cicadettinae, and they occur on all continents except Antarctica.

17-year cicada, or magicicada
The largest cicadas are in the genera Pomponia and Tacua. There are some 200 species in 38 genera in Australia, about 450 species in Africa, about 100 in the Palaearctic and exactly one species in England, the New Forest cicada, Melampsalta montana, which is widely distributed throughout Europe. There are about 150 species in South Africa.

Most of the North American species are in the genus Tibicen – the annual or dog-day cicadas (named after the “Dog Days” because they emerge in late July and August). The best-known North-American genus is Magicicada, however. These periodical cicadas have an extremely long life cycle of 13 or 17 years and emerge in large numbers. Another American species is the Apache cicada, Diceroprocta apache.

38 species from five genera populate New Zealand, and all of the species are endemic to New Zealand and the surrounding islands (Norfolk Island, New Caledonia).

Diemeniana frenchi, an Australian species
Adult cicadas, sometimes called imagines, are usually between one to two inches long. Although there are some tropical species that reach six inches, e.g. Pomponia imperatoria from Malaysia. Cicadas have prominent eyes set wide apart on the sides of the head, short antennae protruding between or in front of the eyes, and membranous front wings. Desert cicadas are also one of the few insects known to cool themselves by sweating, while many other cicadas can raise their body temperatures voluntarily to around 104°, even when the air temperature is only 65°.

Male cicadas have loud noisemakers called “tymbals” on the sides of the abdominal base. Their “singing” is not stridulation as in many other familiar sound-producing insects like crickets (where two structures are rubbed against one another): the tymbals are regions of the exoskeleton that are modified to form a complex membrane with thin, membranous portions and thickened “ribs”. They rapidly vibrate these membranes with strong muscles, and enlarged chambers derived from the tracheae make their body serve as a resonance chamber, greatly amplifying the sound. Some cicadas produce sounds louder than 106 dB (SPL), among the loudest of all insect-produced sounds. They modulate their noise by wiggling their abdomens toward and away from the tree that they are on.

Only males produce the cicadas’ distinctive sound. Both sexes, however, have tympana, which are membranous structures used to detect sounds; thus, the cicadas’ equivalent of ears. Adult cicadas have a sideways-ridged plate where the mouth is in normal insects.

Sound comparison of multiple cicadas from indoors to outdoors.

Cicadas are the most efficient and loudest sound-producing insects in the world. Conversely, some small species have songs so high in pitch that the noise is inaudible to humans. Only the males resound as a mating ritual to attract a female and many cicada species tend to gather when calling which increases the total volume of noise. Species have different mating songs to ensure they attract the appropriate mate.

Cicada Song
Cicadae are unique in sound-producing insects in that they have a musical drum in their abdomen. The organs that produce sound are ‘tymbals’ ~ paired membranes that are ribbed and located at the abdominal base. Contracting the internal tymbal muscles yield a pulse of sound as the tymbals buckle inwards. As these muscles relax, the tymbals return to their original position. The interior of the male abdomen is substantially hollow to amplify the resonance of the sound. The song intensity of the louder cicadas acts as an effective bird repellent. Males of many species tend to gather which net a greater sound intensity and engenders protection from avian predators.

Sound of a single cicada in a tree in front of LIFETIME FITNESS in Schaumburg, Illinois [MAP/SAT]. There was not enough time to get an image of the cicada because LIFETIME FITNESS staff requested the camera be turned off on the LIFETIME FITNESS property. The location is a new construction (less than 17 years-old).  Older trees in a creekbed were undisturbed during construction at the back, northside of the property and Busse Woods (Ned Brown Forest Preserve) is located about one mile east of the location. A sma
ll wooded area is also located, just south across Higgins Road (Route 72).

In addition to the mating song, many species also have a distinct distress call, usually a somewhat broken and erratic sound emitted when an individual is seized. A number of species also have a courtship song, which is often a quieter call and is produced after a female has been drawn by the calling song.

Cicada Life Cycle
After mating, the female cuts slits into the bark of a twig and deposits her eggs there. She may do so repeatedly, until she has laid several hundred eggs. When the eggs hatch, the newborn nymphs drop to the ground, where they burrow and start another cycle. Most cicadas go through a life cycle that lasts from two to five years. Some species have much longer life cycles, e.g. the Magicicada goes through a 13- or even 17-year life cycle. These long life cycles are an adaptation to predators such as the cicada killer wasp and praying mantis, as a predator could not regularly fall into synchrony with the cicadas. Both 13 and 17 are prime numbers, so while a cicada with a 15-year life cycle could be preyed upon by a predator with a 3- or 5-year life cycle, the 13- and 17-year cycles allow them to stop the predators falling into step.

The insects spend most of the time that they are underground as nymphs at depths ranging from about one to eight and one-half feet. The nymphs feed on root juice and have strong front legs for digging.

In the final nymphal instar, they construct an exit tunnel to the surface and emerge. They then moult on a nearby plant for the last time and emerge as an adult. They shed their skins when they moult, and their abandoned skins are often found still clinging to the bark of trees.

The males live until mid-June and the females live into July. A new generation of cicadas will hatch weeks later and burrow into the earth for another 17 years.

Cicadas as Pests
When female cicadas make slits in small branches of trees to lay eggs, the small slits can damage young trees and shrubs. Landscapers and homeowners put colorful, fine netting, known as tulle over entire small, young trees to prevent infestation. A lot of lavender and bright green tulle netting has been spotted in Arlington Heights, Illinois.

Tulle Netting to Protect Trees and Shrubs