This week for Flora and Fauna Friday it’s the symphony of the South, the orchestra of the orchard, and the chorus of the forest: the Annual Cicadas, specifically genus Megatibicen and Neotibicen.
I’m sure you’ve heard before about the mass emergences of Periodical Cicadas (Magicicada spp.) that occur at regular but lengthy intervals. Here in South Carolina we only have one brood of 13 year Cicadas to speak of for that genus (Brood XIX). Unique as they may be, we’re not talking about them today because they’re not found on Edisto Island. Today we’re discussing the Annual Cicadas found throughout the Lowcountry, specifically the large bodied species of Megatibicen and Neotibicen. These species can be painfully hard to differentiate. So we’ll just discuss them at the generic level.
The Annual Cicadas, as the name suggests, come out every year to serenade us with that white noise wailing synonymous with southern summer. A sound to clog our ears like the humidity smothers our skin and the sun sears our eyes. Annual as they may seem, the species does not complete its life cycle in a single year. Each annual emergence only represents a subset of the population. The nymphs live underground for several years where they feed on the sap of tree roots. In the heat of summer they crawl a short ways up a tree trunk into the steamy air to begin their terminal molt. Their exoskeleton splits along the back and a squishy green adult Cicada emerges. The adult lingers as it flushes its wings and solidifies its skin before climbing out of harm’s way to complete the transformation. Left behind is the exuviae, or shed exoskeleton, of the nymph. This shed is usually a translucent yellow-brown in color and, though delicate, will remain clamped to bark or a wall until dislodged and then appropriately repositioned on the t-shirt of an unsuspecting friend. Adults come in many colors and patterns but most are a complex, cryptic blend of browns, greens, blacks, and grays. Their body plan, however, is fairly consistent. A chunky two inch long teardrop-shaped body, long diamond-shaped wings, large spherical eyes set wide on a rounded face, and a mask-like “mouth” of horizontal ribs. Adults feed like their larvae on tree sap, except they eat the above ground kind.
The song of the Cicada is their mating call. Males produce a loud vibrating call using organs on the abdomen called the tymbals. The tymbals are a pair of membranes near the base of the abdomen that the Cicada vibrates rapidly to produces a sound, which then resonates through their body and bounces off their perch to project their voice into the air. In concert, their calls can be deafening beneath the boughs of a shade oak. Females can call as well but reserve their voice for defense, screaming if slighted to startle would be predators. Despite their willingness to be heard, Cicadas are often difficult to find with the eye. Their cryptic colors, static habits, and preference for perches around the tree canopy can make it hard to lay eyes on one, even when you’re trying. However, look not and they seem to fall, almost quite literally, into your lap whirling with a chattering screech.
