Sounds of summer
When I was a kid growing up in Seattle the sound I remember most in the summer was the grasshoppers as they flew away when you’d get to close. Interestingly, I don’t hear those sounds around Seattle anymore. But several years ago when I lived in Arlington, Virginia I heard and then saw something new that I now associate as the sounds of summer. One of those sights and sounds was the firefly. I had many of them outside my window in the spring and summer that I could watch as they lit up the near ground dusk sky while they were searching for a mate. But there was another sound that at first was very strange and eerie to me. The sound is that of cicadas as they are on their mission to find a mate. Cicadas are not commonly known as an indicator species but I do believe that we should consider placing them in this category.
In 2004 I was witness to the brood X emergence of the periodical cicada. Where I was located, the emergence was not as mind-numbing as had been expected and that other areas experienced. I feel that we have had an impact on the habitat that the cicada calls home through our development of open spaces and from our use of pesticides. The cicada is telling us that we need to be more aware of what we are doing.
There are some 3000 different species of the cicadas in the world. The most common are those that appear annually in the “dog days” of summer. These were my first exposure to the wonderful world of cicadas. The “dog day” cicadas generally appear in late July through early September in the mid west, eastern, and southern states of the US and have a life cycle of 2-8 years. This paper focuses on the periodical cicada known as Magicicada. The key difference with the Magicicada is their life cycle ranges from 10-17 years, with the most common have a 13 and 17 year cycle. I’ve mentioned life cycle a couple of times in this paragraph because it is key to the value of the cicadas to us and our environment.
The cicada has a life pattern that has certain aspects which can be related to or mimicked by salmon returning “home” to spawn. A juvenile cicada lives underground getting nourishment from sucking root fluids from trees. They can live anywhere from several inches to several feet underground depending upon their age and nature of the soil. There are at least 5 distinct juvenile stages that require the cicada to shed its nymphal skin. In one of these stages an interesting event happens, some of them stop growing in a way that is reminiscent of hibernation, but more accurately described as dormancy (The four year dormancy period: The Ecology, Behavior, and Evolution of Periodical Cicadas, 1). It is as if time stood still for four years. This is the big difference between the 13 year broods and the 17 year broods. In the spring of their final year they construct exit tunnels to the surface. Then one magical night, they emerge sometimes in mass to begin their final stage of life. They shed their skins once above ground. Within hours their familiar exoskeleton has darkened and hardened as they climb up the tree that has given them nourishment for their life time. Their goal is to find a mate and reproduce.
The males use their “songs” to attract a mate. Once they have found a receptive mate the female cuts a notch in a branch of the tree and will deposit her eggs. Each female cicada can lay up to 600 eggs which take between 4 to 6 weeks to develop into nymphs (Cicada life cycle, 2). In perfect conditions of dense forests the population of the cicadas can hit 1.5 million per acre (How many Cicadas are expected, 3). The numbers can be staggering but are needed to maintain the population due to predation. Having finished their purpose and reproduced. The cicada now dies.
When the nymphs hatch they fall to the ground and burrow into the soil to find a tree root that will help sustain them in their growth and their 17 year cycle. I can tell you from first hand experience that the emergence of the periodical cicada is something to be seen and nothing compares with the shock and then fascination. You first see the holes in the ground, and then see the discarded molted skin before you notice the white adults as their skeleton hardens while they are climbing up the tree, and finally you hear their mating call and clumsy at best flying ability as they find a partner … it’s a sight to behold.
But what does the cicada do for us and our environment? They are incredible work horses for the environment. From beginning to end they are producing positive effects. Because of the shear numbers of periodic cicadas, they help enliven the food web. Many animals feast on cicadas including humans. There is even a cicada cookbook out there on the Internet for the brave souls that want to try something a little different (Cicada recipes, 4).
Once the cicada has died they add Nitrogen to the ground cover and soil which helps promote tree and plant growth. There was a concern that when the cicada deposits her egg through a notch in the branch of a tree that there would be damage resulting in death. The opposite actually occurs. It has been shown that in the following years there is more growth in the trees that have played a part in the cicada emergence. Cicadas also help aerate the soil with their tunnels. But the biggest advantage they have given us is the ability to show us how we are treating our environment.
I had been told what to expect with the emergence of the 17 year cicada by friends who had been through it in 1970 and 1987 and by the media. A friend had told me that you couldn’t take a step without hearing the crunch of a cicada underfoot and that I’d see people with shovels scooping up the molted skins. But this is not what I experienced. Yes, there was many and at times the sound was deafening.
I remember taking a walk to the store and hearing this swarm that was a couple of blocks away. The sound was like that of a flying saucer from a 1950’s or 1960’s movie. But even my friends that had seen previous emergences were remarking that it was not like the past. Yet, I asked a friend of mine who had to travel to a suburb of Baltimore during that time what her experience was. She stated that the cicadas were so intense on the highway that she had to roll up her windows to keep them from flying in. And when she reached her destination she couln't walk anywhere without stepping on them. She had never seen a cicada year like that. So why was there such a difference? In the case of the metro DC area and Owings Mills, Maryland the answer may lie in development and pesticide use.
Cicadas need soil and trees to live. They can not live when you take out the trees and cover the soil with cement, asphalt, monuments and memorials, or homes. That is the big difference between Arlington and the open undeveloped space at Owings Mills. Populations of cicadas have been greatly affected by the loss of their habitat from “destruction of woodlands, forest fires, urbanization and deforestation, and forest loss due to Gypsy Moth” (Habitat preferences: The Ecology, Behavior, and Evolution of Periodical Cicadas, 1 and Cicadas Devastated by Urbanization, 5).
Recently, there has been spraying against the spread of mosquitoes that can carry the West Nile virus and may have also had an impact on the cicada community. Another interesting aspect to this story deals with how we have used pesticides in the past in relation to the periodic cicada.
I was able to read stories from the Washington Post telling residents who were worried about the health of their trees and shrubs what to expect from the emergence of brood X for the years 1970, 1987, and 2004. In 1970 they were recommending people use pesticides to protect their homes and gardens.
From a 1987 article, “experts recommend that we use no chemicals, not even the commonly used pesticide Sevin (a brand of carbaryl), against cicada swarms. An even harsher warning against bug sprays is sounded from entomologists who are concerned about the survival of this unique species of cicadas” (Fenyvesi, 6). Even in 1987 there was concern about the role and health that cicadas play in their habitat. We were learning but did we figure things out before it was too late? I have hope.
The great news from an emergent event like the periodic cicada is that the media has a habit of over hyping. In the case of periodic cicadas the hyping of an emergence can make more people aware of their surroundings and environment. When the hype fails to deliver as promised, you are led to question why and how or the cause and effect. Critical thinking follows and that is always a beneficial action. The questioning will lead to research and that is just what several of the mid west and east coast universities have done.
Much of the information gleaned for this paper has come from research done at major universities like the University of Maryland and the University of Michigan. There is another school of thought that would classify the brood X as an endangered species (What Happened: the Magicicada No-Show of 2004 - Cicada Mania, 7). I feel that this measure may be to extreme at this point in time. But we need to help the Magicicada cicada so that our children and grandchildren will see the fascination of the 17 year emergence cycle.
I have a couple of suggestions that may help protect the periodic cicada. My first suggestion is “smart development” with the environment in mind. There is a community in Arlington, Virginia that has had incredible population growth because of its proximity to the Metro subway. Condos and cement has taken the place of small business with trees and shrubs. I feel that a new phase of development should occur now in this community. My idea would be to put a new tree and shrub lined median in the center of the road. It may take 34 to 51 years for the cicadas to take up residence but the trees will be less likely to be damaged from the minimal impact they have. This median would also help to shield road noise and help to improve the surrounding air quality. Additionally, when a new development is approved there should be environmentally productive trees and shrubs planted on site. This would have a good effect on the intangible quality of life issues that can play into where we choose to live. When we start planting new trees we also have to think about what type the cicada will feel at home with. As luck would have it several of the trees can add those magical colors that permeate the landscape during autumn. These trees could be Ash, Elm, or Oaks but should always be whatever is native to the given ecosystem. The trees at the apartment complex I lived at were maples, and the cicadas were plentiful.
I’ll have to wait until 2021 to hear the sounds of the Magicicada cicadas again. It was an event that made me think about the wonders of nature. This paper is the end-product of that encounter. For over two years I’ve been trying to understand why the emergence of 2004 was so disappointing in the metropolitan DC area. I asked myself, was it over hyped in the media or was there a root cause that needed to be articulated and addressed? The answer is yes to both questions and statements. In our search for desirable housing we have degraded the habitat of the periodic cicada. In our quest for eradicating pests and virus containing insects we have also put into question whether the periodic cicada will reemerge again in 2021. We can do better. We must do better. The cicada is an indicator species … it indicates that we have done harm to our environment and its home. When I returned to Seattle after the 2004 Magicicada cicada emergence; I gave my niece a little balsa wood cut out of the cicada. I hope that in 2021 she will be able to see and hear the real thing. I also hope that I will be with her explaining all of the sights and sounds of this wondrous insect know as the Magicicada cicada and then she will understand why it’s the sound of summer.
1-The four year dormancy period: The Ecology, Behavior, and Evolution of Periodical Cicadas and Habitat preferences: The Ecology, Behavior, and Evolution of Periodical Cicadas
2-Cicada life cycle
3-How many Cicadas are expected
5-Cicadas Devastated by Urbanizationl
6-Charles Fenyvesi "Sing a Song of Cicadas; Gardeners Shouldn't Fear Return of the 17-Year Swarm :[FINAL Edition]. " The Washington Post (pre-1997 Fulltext) [Washington, D.C.] 14 May 1987,t26. National Newspapers (5). ProQuest. SCCC library, Seattle, Washington. 12 Aug. 2006
7-What Happened: the Magicicada No-Show of 2004 - Cicada Mania