Wednesday, August 28, 2013

Backyard Nature Wednesday: Cicadas

Late summer afternoons in my backyard are the Time of the Cicada. The "songs" of the male cicadas as they attempt to attract mates provide a constant background music for my outdoor activities.

The males rest on tree trunks and branches and produce a periodic whine by means of two special vibrating membranes in the sides of the abdomen. The females do not sing, but they are an avid audience for the males' performance.

Here in Southeast Texas we did not participate in the periodical cicada madness that occurred earlier this year in the eastern part of the country. The 17-year cicada does not occur here, although there is one that completes its life cycle in 13 years, some of which emerge every year, rather than in massive broods. Our main type of cicada, the ones that are singing in my backyard now, are called dog-day cicadas because they emerge at this time of the year. They have life cycles of 2 to 5 years.

 These cicadas occur in a wide range of colors in brown and green. Here is a brown one...

...and here is one that is green. I generally see more of the brown variety in my yard.

The female cicadas insert clusters of eggs into twigs and small branches, using a saw-like egg laying structure. It takes six to seven weeks for small nymphs to hatch from the eggs. They drop to the ground and burrow into the soil where they find tree roots.

The nymphs molt through several growth stages, called instars. As they go through these stages, they can burrow several feet down. When the nymphs are fully developed, they burrow out of the ground at night, leaving a 1/2-inch hole behind.

The nymphs then climb onto tree trunks, low plants or other objects and the adult cicadas emerge from the nymphal stage through a crack along the back and leave the light brown cast skin behind.

When I was a kid, I was always fascinated by finding these empty shells clinging to the trunks of trees.

The adult dog-day cicada can live for 5 to 6 weeks, if they can avoid hungry birds. The adults do not feed on leaves but may suck juices from tender twigs. The nymphs feed on the sap from tree roots. Neither is considered to be a plant pest. Indeed, they are benign creatures that just want to sing their songs, mate, lay their eggs, and live out their short summer lives.

Summer would hardly be summer for me without these interesting insects. I even like their song.

2 comments:

  1. Wonderful post! You have me warming up to the cicadas. It's not that I've ever minded them overmuch; as you note, they're not deafening here. I know we have them in our garden, but I've never seen them. Now, I feel I must know if they are green or brown!

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    1. They are fascinating insects and, actually, I quite like their music. Summer just wouldn't be the same without them.

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