Big Cicada Emergence, Implications on Food Webs

Estimated read time 4 min read

John Lill, a biology professor at George Washington University and Martha Weiss, a Georgetown University environmental studies professor, observed cicada activities on June 13, 2024, in Lake Forest’s Middlefork Savanna Forest.

In Lake, researchers watched ants interacting with cicadas. The actions of these ants provide valuable insight into the changes in forest food webs when huge numbers of cicadas emerge.

So, says researcher Sean Menke an ant expert and nature professor at Lake Forest College who wants to understand the connections within this natural phenomenon.

The reappearance of cicadas after their years of hibernation can trigger substantial shifts in energy flows within ecosystems. Research shows that birds heavily feed on cicadas during emergence years, reducing predation on caterpillars which could boost their damage to oak trees.

“It is thrilling and challenging because we are still learning,” Menke commented.

 

Lots of Food for Predators during Cicada Emergence

This year Illinois will witness double cicada activity from both Brood XIX and Brood XIII. Such concurrent appearances last happened two centuries ago in 1803. This enormous rise saturates the ecosystem with resources confusing predators by sheer numbers while lessening predation risk.

Ecologist Zoe Getman-Pickering, who works with UMass Amherst’s Energy Transition Institute noted how easy it is to catch cicadas owing to their bulky size and slow flight.

Brown bears and spider monkeys also enjoy eating these insects as healthy alternatives,” said Senior Vice President of animal health at Brookfield Zoo Sathya Chinnadurai.

Previously, during Maryland’s 2021 Brood X emergence, researchers witnessed a variety of birds feasting on cicadas which resulted in a spike in caterpillar numbers and their damage to oak trees.

“Going by these changes, Illinois birds may behave similarly,” suggested Getman-Pickering.

 

Effects of Cicada Emergence on Forest Health

Despite initial damage, trees tend to recover rapidly. In fact, decomposing cicada remains can add nutrients to the soil benefiting oaks while birds get a feast from the cicada emergence.

This temporary relief might also help bird population growth said Getman-Pickering.

 

Ants, Overlooked Ecosystem Helpers

In Lake Forest, Researchers Weiss and Lill observed that ants play an important role in ecosystem dynamics during cicada emergences due to their altered behaviors.

“Ants are the overlooked heroes of many forests,” commented Weiss.

Dying cicadas during emerging years become an alternate food source for ants. However, if ants avoid their usual foraging duties it could impact ecosystem balance says Lill.

The team placed different food items within the forest. Normally omnivorous ants who have easy access to them may neglect other nutrients like sugar which they usually get from aphids thereby leaving them exposed to predators. “Ants ignoring aphids make them easy prey,” explained Weiss.

 

Longterm Effects of Cicada Emergence

The study set to complete by 2026 aims at understanding pattern changes post cicada emergence among various creatures like birds, ants and more.

 

Mass Cicada Emergence Causing Disturbance

In April, cicadas belonging to Broods XIII and XIX surged in Midwest and Southeast US and caused disruptions. PhD student at Florida State University, Grace Soltis, believes these emergences alter the diets of entire bird communities besides giving predators a feast.

 

Cicadas Afflicted by ‘Zombie STD’

Cicadas sometimes suffer from a fungal parasite called Massospora cicadina causing strange behavior’s including frantic mating till death. But this doesn’t eliminate cicadas according to biologist John Cooley from the University of Connecticut.

 

2024’s Double Cicada Emergence is Uncommon

Birds adapt most to these emergences. So, says Lill whose study with Soltis identified during Maryland’s 2021 emergence over 80 species switched their diets to cicadas, causing an increase in caterpillar numbers thus more tree damage.

“Undisturbed food sources have implications on the food web,” Lill stated.”

Longterm Effects of Cicada Emergence Not Yet Clear

In such year’s bird population increases likely causing further impacts reassures Lill. Next year, emergence events present chances to examine resource surges and their effects on food chains.

Even with all the confusion cicadas promote soil nutrient recycling and improve water seepage. But not much is known about the immediate impacts of living cicadas on food chains.

John Lill stated, “Higher temperatures will result in cicadas appearing earlier in the year, leading to an escalation in sudden, strange, timed occurrences.”

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