Why We Don’t Hear the 17-year Cicadas here in Florida
June 7, 2013
Lately, the media have been reporting on the cicadas that have emerged in the Washington, D.C. area after spending the last 17 years underground. One reason we may be hearing so much about this particular emergence is the concentration of population and proliferation of media in the area. Folks who crave hearing their deafening mating calls — among the loudest sounds produced in nature — can do so almost any year. They just have to travel to the right place.
Entomologists have dubbed this particular group “Brood II.” Actually, there are 12 broods (a brood is defined as a group having a common nature or origin) of 17-year cicadas. In May of their year of emergence, when the temperature reaches 64 degrees, the cicada nymphs tunnel to the surface and crawl onto trees. There they shed their skins and the males begin singing to attract the females. Females lay 400 to 600 eggs in the branches of trees; nymphs hatch, then drop to the ground and begin burrowing. This all happens in less than four weeks. By July, all of the adults will have died.
Click here to view a beautiful video trailer documenting the cicadas’ 17-year life cycle in just seven minutes, produced by Samuel Orr for an upcoming PBS documentary.
Often heard; seldom seen
While you won’t encounter the 17-year varieties in Florida, you can hear the calls of their southern cousins and see their cast-off nymphal skeletons on tree trunks and shrubs. (Entomologists at the University of Florida have posted the calls of a number of North Florida species here.)
Florida’s cicadas are not without their quirks. Females are sometimes attracted to power tools and lawnmowers. It appears they are mistaking the noises from the tools for the mating calls of the males. They don’t seem to cause much damage to Florida crops, although one species, Tibicen davisi, was reported in the 1930s to have damaged a type of asparagus fern, Asparagus plumosus, grown for use by florists. Ferneries have reported no such damage in recent years. That may be because Asparagus virgatum, which has largely replaced A. plumosus as the main crop grown in Florida ferneries, is less susceptible.
Another cicada species, Diceroprocta viridifascia, once caused another kind of economic harm. Seems their raucous daytime chorus interfered with a movie company’s sound track for scenes it was filming at a beach near St. Augustine.
For more about Florida cicadas, visit this Featured Creatures page by UF/IFAS and FDACS/DPI Entomology and Nemotology.