The cicadas are coming.
According to the University of Kentucky Department of Entomology Kentucky will be the epicenter for the emergence of Brood XIV of 17-year periodical cicadas this spring.
The largest emergence area will occur across most counties in the eastern two-thirds of the state.
The life cycle and life history of cicadas is intriguing.
Superfamily
The cicadas are a superfamily of insects, first described in the scientific literature in 1802.
The superfamily is divided into two families, the Tettigarctidae, with two species in Australia, and the Cicadidae, with more than 3,000 species worldwide.
Australian cicadas are found on tropical islands and cold coastal beaches around Tasmania, in tropical wetlands, high and low deserts, alpine areas of New South Wales and Victoria, and large cities including Sydney, Melbourne, and Brisbane. The Australian greengrocer, Cyclochila australasiae, is one of the loudest insects in the world.
Cicadas are also present in New Zealand and Europe.
There are about 150 species in South Africa, over 170 species in North America, at least 800 species in Latin America, and over 200 species in Southeast Asia and the Western Pacific.
Many species of cicadas have not be described in the scientific literature.
Nearly all cicada species are annual cicadas with the exception of the few North American periodical cicada species, genus Magicicada, which emerge in various regions every 13 or 17 years.
The vast majority of cicada species are active during the day as adults. Only a few rare species are known to be nocturnal.
Emergence
The 17-year periodical cicadas emerge from the soil to molt into their flying, adult form, leaving behind their exoskeleton shells usually on tree trunks. Periodical cicadas emerge much earlier in the year than annual cicadas, when soil temperatures climb in the 60s.
Periodical cicada nymphs live in the soil, feeding on the sap of tree roots. According to the University of Kentucky Department of Entomology cicadas count their feeding cycles to know when to emerge.
The annual cicadas are species that emerge every year. Though their life cycles can vary from one to nine or more years as underground nymphs, their emergence above ground as adults is not synchronized, so some members of each species appear every year.
Size and coloration
As imagined, with so many species worldwide, size and coloration varies considerably.
The cicadas we see here in Kentucky are typically about 1 1/2 inches long.
The largest species, the empress cicada (Megapomponia imperatoria), has a body length of almost three inches, and a wingspan of seven to eight inches.
The periodical cicadas in Kentucky have prominent red eyes set wide apart, short antennae, a black body, orange “feet” and orange veins on their clear membranous wings.
Song and reproduction
The adult cicadas loud song is a high-pitched buzzing produced by a tymbal, a drum-like corrugated exoskeletal structure in the abdomen. Only males can produce the sound.
Their calling has two functions, to encourage other males to congregate, and to attract females. In Kentucky, cicada calling usually starts in mid-May.
The males die shortly after mating. Then the females begin laying eggs, typically 200 to 600, in a slit in tree bark, or by boring their ovipositor, a specialized tube-like organ for depositing eggs, into young, tender tree or shrub branches.
When the eggs hatch, the newly hatched nymphs drop to the ground and burrow. Cicadas live underground as nymphs for most of their lives at depths down to about eight feet. Nymphs have strong front legs for digging and excavating chambers near to roots, where they feed on xylem sap.
While egg laying by large numbers of periodical cicada can be problematic for orchards, tree nurseries and landscapers, Jonathan Larson, extension entomologist at UK suggests “cicada netting, which prevents females from laying their eggs, on new and small trees.”
A food source for wildlife
A mass emergence of cicadas creates a bounty of food for a wide variety of wildlife.
Large numbers of cicadas influence wild turkey numbers by affecting the survival of newly-hatched poults. The insects provide an abundance of food for poults, and since cicadas are also eaten by other animals, including potential wild turkey predators, there’s a higher survival rate of poults.
A mass emergence of cicadas is a rarity, a wonder of nature. Embrace the “buzz,” and if you want to handle a cicada, go ahead. They don’t bite or sting.