Month: January 2022

Top row, left to right: cicada egg (Roy Troutman), freshly hatched nymph (Roy Troutman), second and third instar nymphs (Elias Bonaros). Bottom row, left to right: fourth instar nymph, teneral adult, adult. (Cicada Mania).

Cicadas begin life as a rice-shaped egg, which the female deposits in a groove she makes in a tree limb, using her ovipositor. The groove provides shelter and exposes the tree fluids, which the young cicadas feed on. These grooves can kill small branches. When the branches die and the leaves turn brown, it is called flagging.

Once the cicada hatches from the egg it will begin to feed on the tree fluids. At this point, it looks like a termite or a small white ant. Once the young cicada is ready, it crawls from the groove and falls to the ground where it will dig until it finds roots to feed on. It will typically start with smaller roots of grasses and work its way up to the roots of its host tree. The cicada will stay underground from 2 to 17 years depending on the species. Cicadas are active underground, tunneling, feeding, and not sleeping or hibernating as commonly thought. Cicadas go through multiple phases, called instars, while underground. Magicicada have five instars.

After the long 2 to 17 years, cicadas emerge from the ground as nymphs. Nymphs climb the nearest available vertical surface (usually a plant) and begin to shed their nymph exoskeleton. Free of their old skin, their wings will inflate with fluid (hemolymph) and their adult skin will harden (sclerotize). Once their new wings and body are ready, they can begin their brief adult life.

Adult cicadas, also called imagoes, spend their time in trees looking for a mate. Males sing (or otherwise vibrate the air or their surroundings), females respond, mating begins, and the cycle of life begins again.

There are three types of cicada life cycles:

Annual: Cicada species with annual life cycles emerge every year, for example, Swamp Cicadas (Neotibicen tibicen) emerge every year in the United States, and Green Grocers (Cyclochila australasiae) emerge every year in Australia.

Periodical: Cicadas species with periodical life cycles emerge together after long periods of time, for example, Magicicada septendecim will emerge every 17 years (Find out where they’ll emerge next). Magicicada periodical cicadas are organized into Broods, which correspond to the series of years in which they will emerge. Only periodical cicadas are organized by Roman-numeral Broods.

Protoperiodical: Cicada species with protoperiodical life cycles might emerge every year, but every so many years they emerge together in large numbers, like certain Okanagana depending on factors like proximity to other species and rainfall accumulations (Chatfield-Taylor 2020).