U.S. sees cicada double-whammy

Billions of cicadas from two different broods are set to emerge from underground in an ultra-rare synchronised event not seen for 221 years


Brood XIII emerges every 17 years, and Brood XIX has 13-year cycle

Broods last aligned in 1803, when Thomas Jefferson was president. Will not occur again until 2245

Broods may overlap and interbreed in parts of Illinois – rare event is exciting entomologists


IA WI IL IN UNITED STATES MO KY VA AR TN NC MS AL GA SC
200km 125 miles

Brood XIII 
Brood XIX


LIFE CYCLE

1 Nymph
2 Moult
3 Adult
4 Eggs

7-10cm


1 May-Jun: As soil temperature reaches around 17°C, nymphs burrow up from below ground

2 After final moult, nymph’s skin splits open and cicada emerges

3 Fully mature cicadas mate – males belt out distinctive call to attract females

4 Jul: Females lay eggs in trees which hatch four to six weeks later – offspring head back underground to begin next cycle


Sources: Reuters, The Cicada Project at the University of Connecticut 
Pictures: Newscom, White House Historical Association
© GRAPHIC NEWS