The cicadas that synchronize their emergence with others have a better chance of survival. Scientists believe that the simultaneous emergence of insects is an evolutionary strategy. Predators like birds and raccoons can only consume a limited amount, so the more cicadas emerge together, the higher their chances of survival, reproduction, and passing on their genes. “They have a strategy of safety in numbers,” explains Chris Simon, a professor of ecology and evolutionary biology at the University of Connecticut.

On the other hand, rare cicadas that emerge out of sync are often referred to as “strays.” These stragglers are usually preyed upon and struggle to survive. “Natural selection favored those that waited, because those that couldn’t wait were eaten,” Simon said.

This summer, two cicada broods are expected to emerge simultaneously, leading to a particularly large population of periodic cicadas. The last time such an event occurred was in 1803. The organization behind the Cicada Safari app, which aims to track cicada sightings and help scientists study these insects, has already recorded over 1,000 sightings in Georgia and hundreds more in North Carolina and Alabama.

Periodic cicadas are categorized into two groups based on their emergence period: those that appear every 13 years and those that appear every 17 years. While temperature seems to trigger their emergence, the exact mechanism behind how they synchronize their emergence remains somewhat mysterious. Scientists have observed changes in cicadas’ emergence patterns, speculating that rising temperatures due to climate change may be impacting their internal clocks.

Entomologist Gene Kritsky notes that global warming is causing cicadas to emerge earlier in the year due to higher average temperatures. This shift in emergence time has been observed to be approximately 10 days to two weeks earlier than in 1940. Researchers like John Cooley predict that cicadas’ distribution will shift northward as the climate warms and their preferred plant species move north.

There has been an increase in reports of stragglers, intriguing researchers in the field. Simon and her colleagues believe that climate change may be influencing the emergence of cicadas earlier than usual, leading to the formation of new populations among stragglers. This adaptation is seen as a response to a warming climate and extended growing seasons.

Simon proposes a theory that rising temperatures may prolong the development of cicadas underground, resulting in the emergence of more stragglers sooner than expected. Eventually, the population as a whole may adapt and change its timing. She predicts that the 17-year cicada broods may transition to a 13-year cycle and possibly even emerge every nine years.

If proven correct, this theory would be another example of how climate change is disrupting natural rhythms in the environment. Periodic cicadas, harmless to humans, range across the eastern United States to the Midwest and emerge in special events rather than yearly like annual cicadas.

While scientists continue to study how cicadas coordinate their mass emergence, they have yet to discover a precise explanation for their successful synchronization. A recent study suggests that underground communication could be a potential factor worth investigating further. “No one has ever studied this,” Simon said.