Take Me Outside: A look at cicadas
A female cicada lays eggs on a tree branch in this undated handout photo, from the University of Illinois, in Champaign. The noisy, red-eyed periodical cicada is starting to emerge for their weeks-long frenzy of molting, mating and egg laying. Illinois has occurences of 13-year and 17-year life cycle. (AP Photo/University of Illinois, James Appleby)
Hazel Prunier of Nashua prepares to enter a facial scanner during a seminar for hair professionals sponsored by the Melanoma Foundation of New England Monday, July 22nd, at the Puritan Conference Center in Manchester. The MFNE, based in Concord, MA, conducts seminars for hair professionals throughout New England, instructing attendees to recognize signs of melanoma on their clients. The Foundation reasons that hair professionals are in a unique position to screen their clients for the deadly disease since they see clients many times in a year, whereas most people see a dermatologist only once a year.
Gil Talbot for the Monitor
When I was growing up we called them “heat bugs” because they buzzed on the hottest days of summer. The high-pitched whine of the annual cicada is usually heard during the hot, “dog days” of summer, so they are also called dog day cicadas. As adults, these insects are 11∕2 to 21∕4 inches long with robust brownish bodies and transparent wings that extend past their backs. Their bulging eyes stick out from the sides of their heads so they don’t at all resemble locusts or tree crickets, though they are sometimes called those names.
There has been a lot of “buzz” lately about cicadas. Periodical cicadas, particularly, have a fascinating life cycle which includes spending 13 to 17 years underground. They garner a lot of attention when they emerge, as they are doing this year – but not in New Hampshire.
All female cicadas lay eggs in the twigs of deciduous trees. When the eggs hatch into nymphs, they fall to the ground and burrow into the soil where they stay for two to 17 years, depending on the species. While underground, they feed on plant roots, sucking the sap, but not causing major damage. They also molt and grow in an unusually long life cycle for an insect. At the appointed time, the nymphs emerge from the ground. Climbing up into a tree, they find a place to transform. Like Superman shedding his Clark Kent suit and springing forth ready to fly, this once land-bound creature splits out of its exoskeleton with large wings bound for higher terrain.
From the tree tops, male cicada advertise their presence using the tell-tale buzzing. The buzz starts out long and continuous, growing with intensity and loudness and dying off at the end. The particular sound, time of day and habitat are unique for each species.
This sound is not made by rubbing their legs together the way crickets and grasshoppers do. Rather they expand and contract a membrane at the end of their thorax. The vibration is amplified by a chamber in the abdomen, making it one of the loudest sounds in the insect world. The “songs” can reach as high as 90 to 120 decibels, or about the level of some power mowers.
All of this behavior is exhibited by our local annual cicadas except they spend only two to five years underground. Because of different broods, we experience them annually in consistent abundance. Late July and early August is typically the best time to listen and watch for them. When you hear them, head for the tree where they are singing. Look on the ground beneath the tree. You may find 1∕2-inch holes left by the emerging nymphs.
The next thing to look for is the exoskeleton of the nymph. These are light brown casings the exact shape of the nymph, including their legs, eyes, wing buds and abdomen. The empty shell will have a slit down the back revealing where the adult broke out of its juvenile wrapper. The casings can be found clinging to the bark of a tree or a branch.
In New Hampshire, the adults are rather difficult to see because they hang out high up in the trees and are usually solitary. However, anywhere south of Connecticut, in the territory of the periodical cicadas, their sheer numbers make them hard to miss. If you have friends or relatives that live there you may have heard stories of the mass emergence of these creatures earlier in the summer. Crunching under feet, darkening garage roofs, filling swimming pools, driving people batty with their sound, these are the tales that come from those regions. Having been in Virginia during an earlier emergence of periodical cicadas, I can attest to the deafening nature of that mass of sound.
But here, we can just search them out, enjoy the warmth of summer that is their catalyst for activity and appreciate the fact that they are benign insects that just make interesting sounds. They are one of the few insects that don’t carry disease, don’t harm plants and don’t sting or bite.
They actually help aerate the soil and provide food for birds and sometimes people. So as summer progresses, be thankful that we live in New Hampshire and that not all insects are like mosquitoes and tomato horn worms!