Monday, May 11, 2015

All You Need to Know About Cicadas

Borrowed heavily from Wikipedia:

Cicadas found in the Southeastern part of the United States are typically of the Magicicada genus. Sometimes mistakenly called "locusts"; however, true locusts are more closely related to grasshoppers. 

Magicicada spend most of their 13- and 17-year lives underground feeding on xylem fluids from the roots of deciduous forest trees in the eastern United States. After 13 or 17 years, mature cicada nymphs emerge at any given locality, synchronously and in tremendous numbers. After such a prolonged developmental phase, the adults are active for about 4 to 6 weeks. The males aggregate into chorus centers and attract mates. Within two months of the original emergence, the life cycle is complete, the eggs have been laid and the adult cicadas are gone for another 13 or 17 years.
Magicicada males typically form large aggregations that sing in chorus to attract receptive females. Different species have different characteristic calling songs. 
Cicadas do not bite or sting. They have mouthparts used in piercing plants and sucking their sap. A cicada's proboscis can also pierce human skin when it is handled, which is painful but in no other way harmful. These cicadas are not venomous, and there is no evidence that they transmit diseases. They pose little threat to mature vegetation, although planting new trees or shrubs is best postponed until after an expected emergence of the periodical cicadas. Mature plants rarely suffer lasting damage, although twig die-off or flagging can result from egg-laying.

Cicadas of all other species (perhaps 3000 worldwide) are not synchronized, so some adults mature each summer and emerge while the rest of the population continues to develop underground.The nymphs of the periodical cicadas live underground, often at depths of 30 cm (1 ft) or more, feeding on the juices of plant roots. The nymphs emerge on a spring evening when the soil temperature at about 20 cm (8 in) depth is above 17.89 °C (64 °F). In most years, this works out to late April or early May in far southern states, and late May to early June in the far northern states. Emerging nymphs climb to a suitable place on the nearby vegetation to complete their transformation into an adult cicada. They molt one last time and then spend about six days in the leaves waiting for their exoskeleton to harden completely. Just after this final molt, the teneral adults are white, but darken within an hour.

Adult periodical cicadas live only for a few weeks—by mid-July, all have disappeared. Their short adult life has one purpose: reproduction. 
Receptive females respond to the calls of conspecific males with timed wing-flicks, which attract the males for mating. The sounds of a "chorus"—a group of males—can be deafening and reach 100 dB. In addition to their "calling" or "congregating" song, males produce a distinctive courtship song when approaching an individual female.
After mating, the female cuts V-shaped slits in the bark of young twigs and lays approximately 20 eggs in each, for a total of 600 or more eggs. After about six to ten weeks, the eggs hatch and the newborn nymphs drop to the ground, where they burrow and begin another 13 or 17-year cycle.
Wild turkey populations respond favorably to increased nutrition in their food supply from gorging on cicada adults on the ground at the end of their life cycle. Uneaten carcasses of periodic cicadas decompose on the ground, providing a resource pulse of nutrients to the forest community.[19]
Cicada broods may also have a negative impact. It has been suggested that Squirrel populations have been negatively impacted, because the egg laying activity of female cicadas damaged upcoming mast crops

1 comment:

golferinmississippi said...

Mississippi State had some information on the MSUcares extension site.

Great information on that PDF as well as the site itself.