“General Periodical Cicada Information.”. Molles, Ecology: Concepts and Applications (6th ed. Although these insects may appear alarming, they do not sting or bite, are not toxic, and do not transmit disease (2).ġ. Dense concentrations of cicadas should reach central Connecticut by late May or early June. This summer, juveniles that have been developing since 1996 are scheduled to swarm in the northeast, from Georgia to New York. Thus, population dynamics of other species are not greatly affected by the cicadas. The predator populations cannot grow in response to the increase in prey supply, because the cicadas are only available as a food source once every seventeen years (2). The adults die shortly after, and the young fall to the ground when they hatch, burrowing underground to start their long development process (2).ĭuring these mass emergences, cicadas swarm in such high densities that predators can eat their fill without making a dent in the cicada population.
Once they have become adults, males fly to treetops and sound their mating calls, using the ribbed vibrating membranes on their abdomen (3).Īfter mating, females lay up to 600 eggs in nests that they dig out in tree branches. To achieve such synchronized movement, the juvenile cicadas wait until the soil reaches a certain temperature before emerging (2). The emergence of periodical cicadas is so well coordinated that as many as 1.5 million per acre can appear practically overnight. Aboveground, they molt and develop a hard adult exoskeleton. They feed on fluid from plant vascular tissue and dig to the surface once they mature. The cicadas that inhabit the northeast spend their first 17 years underground as juveniles, or nymphs. There are several species of periodical cicada that live throughout the eastern United States, with life cycles of either 13 or 17 years. One species that uses this defense is the periodical cicada, an inch and a half long winged insect with a black body and bright crimson eyes (3). The most dramatic of defenses is predator satiation, in which members of a species emerge in such high densities that predators simply cannot consume them all (1). Others, such as aggregation, deter predators from attacking. The timing of the cicadas cycles is all about manipulating their predatorsand 'may have nothing to do with these being prime numbers,' he emphasizes. Some of these techniques, such as camouflage, decrease the organism’s chance of being spotted by a predator. 'The cicadas are driving the birds populations theyre setting the birds on a trajectory that leads to significantly lower populations at the time of the next emergence,' Koenig says. Source: WikimediaĪnimals have developed a wide variety of defensive strategies to avoid being eaten by predators. An adult periodical cicada perched on a blade of grass.
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