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Hear the trees 'screaming'? It's cicada season


Walker's cicada is one of several annual cicadas that hatch yearly and are native to Missouri, and one of the largest — and loudest — species of cicada, according to the Missouri Department of Conservation (MDC).

When the insects emerge as adults from their nymph stage, they leave behind empty brown shells, often found still clinging to tree trunks or outdoor walls. After leaving its "skin," the newly adult cicada’s wings unfurl and dry, enabling it to fly.

Walker’s cicada is one of seven species of annual cicadas in the state, not to be confused with the species that are often called 13-year or 17-year cicadas that emerge periodically during the summer. Annual cicadas, also known as dog-day cicadas, spend about two to five years underground as nymphs, after hatching from eggs laid on tree twigs and falling to the ground. There, the nymphs make a burrow, where they suck the juices out of tree roots, spending the majority of their life cycle there.

The young insects emerge from the ground during July and August to molt into adulthood, attract a mate and lay eggs.

Male cicadas can often be heard making a rhythmic shrill sound, a mating call that begins shortly after they emerge and is made by two drumlike membranes on the sides of their first abdominal segment, say officials with the University of Missouri's Department of Entomology. When they are active, the sound can be "quite loud and incessant," beginning at dawn and stopping in the evening, they note, adding that the volume rises with the day's temperature.

The adult cicada also eats plant juices but usually only has a lifespan of a few weeks, and the insect itself is eaten by birds, spiders and other insects, including a large species of wasp that captures them and feeds them to their young.

Cicadas are also popular bait used by anglers, and in some cultures, are used as a food source for humans, MDC wildlife specialists say.