Dog-day Cicadas

 

Adult Swamp Cicada (Neotibicin tibicin) one of the Dog-day Cicadas.
Rowan County, North Carolina.

In the long, hot, dog days of summer there comes a sound.   The sound begins softly then rises to a crescendo, a roar through the woods. This is the song of the Dog-day Cicadas and is part of their desperate bid to mate, lay eggs and leave the next generation of these large and loud insects. The larval nymph stage emerges from the ground, climbs up a plant and transforms into a flying adult, leaving the exoskeleton of the nymph behind.  Dog-day cicadas appear every summer and are also known as annual cicadas.  This is something of a misnomer because, unlike annual plants, the annual cicadas take at least two years to complete their lifecycle.  However, they are around every summer.  In contrast their relatives, the Periodical Cicadas appear synchronously every 13 or 17 years.  Earlier this summer Brood XIX of the Periodical Cicadas emerged in our area.  It is easy to distinguish the two types of cicadas, Dog-day Cicadas have dark green eyes while Periodical Cicadas have red eyes. 

Dog-day Cicada (Neotibicin sp.) nymph exoskeleton. 
The fissure on the back
is where the adult crawled out.
Rowan County, North Carolina.

There are several different Dog-day Cicadas including those in the genus Neotibicin.  One of these is the Swamp Cicada (Neotibicin tibicin) the most common cicada in eastern North America.   They are dark above, with green behind the head, green legs and green wing veins. 

Adult Swamp Cicada.
Rowan County, North Carolina. 

A second common Dog-day Cicada in our area is the bizarrely named Scissor-grinder Cicada (Neotibicin winnemanna).  From above Scissor-grinder Cicadas are dark with green markings, with two white spots where the thorax meeting the black abdomen.  The underside of this cicada is waxy white.  Their name comes from their call that reminded 19^th century folks of the sound of scissors being sharpened on a grinding wheel.   Most of us 21st century people do not have much experience with scissor grinding but we can imagine it by listening to these calling insects. 

Dead adult Scissor-grinder Cicada (Neotibicin winnemanna)
 seen from above.
Rowan County, North Carolina. 

Dead adult Scissor-grinder Cicada 
seen from below.
Rowan County, North Carolina. 

Periodical Cicadas add drama to the entomological world with their long lifecycles and overwhelming numbers.  But there is something reassuring and steady about the annual Dog-day Cicadas showing up every summer.   As the Grateful Dead sang so insightfully in Terrapin Station Crickets and cicadas sing their rare and different tune".  

Neotibicin sp nymph exoskeleton.
Rowan County, North Carolina.