If you hear a loud buzz coming from trees in the daytime, the noise is most likely caused by cicadas. These buzzing critters make their presence known by leaving their brown exoskeletons on tree trunks and shrubs.
Cicadas can be found throughout North America, including here in Florida.
Sound
The sound of cicadas is distinctive, and species can be differentiated by their calls. Only males can make sounds, most of which are calling songs to attract mates.
The whirs and buzzes of cicada songs can be similar to the sounds of power tools. Some homeowners and contractors have even reported cicadas being attracted to their lawn mowers and power saws.
The reason only male cicadas can produce songs is that they are the only cicadas with timbals—drum-like body parts on the sides of their abdomen. The timbals are a combination of stiff ribs, flexible membranes, muscles, and air sacs that pop in and out and produce sound.
Life Cycles
Cicada nymphs live underground where they feed on sap from the roots of trees, grasses, and woody plants. Not much is known about how long cicada nymphs stay underground—some species have two-year life cycles, but others have life cycles of 10 or more years.
Nymphs will molt four times underground, then climb to the soil surface and up a tree or shrub, and molt a fifth time to become an adult. The skeleton left after this last molt is what people find anchored on tree trunks and other plants.
Cicada adults are strong fliers that will spend most of their time in trees, eating, singing, mating, and laying eggs before they die a few weeks after emerging. When the eggs hatch, the nymphs fall to the ground and burrow into the soil, starting the whole process over again.
Population Cycles
Keep in mind that although cicada species have certain life cycles, not all their broods in the soil are at the same stage in their life cycles. The overall adult population will depend on the size of the broods at the end of their nymph stage that year.
Periodical cicadas are species that have synchronized their development so that they mature into adults in the same year, usually on 13- or 17-year life cycles. News reports and interest pieces are popular around the time these group emergences are expected.
Florida, however, does not have periodical populations of cicadas, and adults emerge every year from late spring through the fall.
Cicadas in Florida
Cicadas are not considered to be a pest of any significance in Florida. They do not require treatment and are best left alone, since any damage they cause is negligible.
Cicadas are active in tree canopies and shrubs in the daytime. They will not swarm or be attracted to people (nor will they splatter on your vehicle).
Sometimes their egg-laying can damage tree twigs. The twigs will break, and the leaves die, causing brown “flags” at the end of branches. This problem is rarely reported in Florida because we do not have large periodical cicada populations.
Cicadas do not bite or sting and do not carry harmful diseases. They are a food source for wildlife and can even be a food source for people.
Adapted and excerpted from:
T. Walker and T. Moore, Cicadas (of Florida) (EENY327), UF/IFAS Entomology and Nematology Department (rev. 10/2014).
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