In the hubris of our human position, we forget sometimes that it is the smaller life forms that make everything possible for us. In his eloquent book The Creation, E.O. Wilson writes, “more respect is due the little things that run the world.” Insects, after all, make up the lion’s share of the world’s species and animal biomass. Entomologist Terry Irwin famously estimated the number of insect species at 30 million globally, with the vast majority yet to be classified and named. And they do much of the work that makes it possible to live—from pollination, to seed dispersal, to waste decomposition, to turning the soil (it is insects that do most of this work, not earthworms, as commonly thought). “People need insects to survive,” Wilson says, “but insects do not need us.”
Insects have biological narratives and lifecycles that can stretch human belief. Here in the eastern US, a case in point are the 17-year cicadas, beginning to emerge in parts of Virginia and other states. Few things in nature are as wondrous or surprising as the emergence of cicada nymphs after 17 years of dormancy, a final flurry of flight, song (in the case of males), reproduction, and then death. It is an insect drama acted out in cities and towns from Georgia to Texas.
These 17-year cicadas are different and distinct species from the annual cicadas we hear each year. They come out in broods, distinct genetic groups, likely a very smart evolutionary strategy. One can even consult a brood map to see which 17 year cicadas (and for some species 13 years) will emerge when and where (I have discovered a terrific website, “Cicada Mania,” with brood table and lots of other great information about 17-year cicada).
This amazing cicada spectacle will be on display for around 6 weeks, in backyards and parks in many cities and suburbs, and it will be a challenge for many of us to see the wonder in their appearance. Unfortunately, too often insects are viewed as icky or ugly or scary, reactions that are quite rare in younger kids, but seemed to be learned or inculcated as they grow up. The last appearance of 17-year cicadas in our area was in 2006, the so-called Brood X. I remember it well, in part because of the surprising, but completely natural reactions of my then-seven year old daughter. I recall her palpable sense of wonder about these creatures. She happily picked up the odd cicada from the ground or a low-lying tree branch, eager to examine it.
While much older now, of course, I’m not sure of what her reaction will be to Brood II (likely the same, I think), but it makes me wonder when the fear of and aversion to insects sets in with kids, and why. Moving forward, part of our challenge in cities will be to find ways to short-circuit these acquired aversions, to turn them on their heads, encouraging kids and adults to witness the immense fun in watching and listening to the insect world around us.
Ants are another important insect that call cities home, and there has been fascinating research recently on the presence and diversity of ants in New York City and Raleigh, NC. The New York work by Mark Pecarevic and colleagues involved sampling with pitfall traps along the medians of Broadway and Park Avenues, finding 13 different species. Urban environments, in the case of ants at least, seem not to diminish diversity, and it appears from these studies that cities may be helpful habitat bridges, allowing ants to adapt to changing climate.
Ants are all around us, but different species are often difficult to identify. One citizen science initiative, the School of Ants seeks to engage urbanites—especially kids—in the collection and sampling of ants around the country. Already some 600 ant samples have been registered and identified on an online data map. One of the most interesting results of this project is an identification flow chart, which can aid in the labelling of individual species.
Appreciation of cicadas and ants may still be lacking, but many cities have developed efforts to conserve more aesthetically appealing species, especially butterflies. Singapore has developed a butterfly trail, for instance (spearheaded by the Nature Society of Singapore), and efforts are underway in San Francisco to piece together a butterfly corridor for the endangered Green Hairstreak.
There is indeed a spectrum of responses to insects in cities, from the “beautiful” to the “icky,” and strategies to move us collectively towards an appreciation of these species remains an open question. Why we look at the distinctive yellow and black markings of a tiger swallowtail butterfly and see beauty, but look at the red eyes and orange wings of the periodical cicada and see icky and ugly, is unclear.
Both the butterfly and the cicada are wondrous and valuable, as well as essential parts of the ecological fabric and biodiversity of cities. Most importantly, they are a critical linchpin of the everyday nature that cities and their inhabitants will need to be happy and healthy.
Want more? Click here to read another blog post by Humans and Nature on cicadas.
Post by Timothy Beatley