Spotted lanternflies are hitching rides to invade new places

Besides warmer weather and blooming flowers, spring also brings the unfortunate re-emergence of the spotted lanternfly, a prolific invasive insect originating from Asia that wreaks havoc on both forests and croplands. Since their initial detection in Pennsylvania in 2014, these insects have spread to over 100 counties across 14 states.

Now, a study published in the journal Nature Scientific Reports has found that the spread of spotted lanternflies is largely due to human-mediated dispersal via transportation by cars, trucks, and trains.

“Spotted lanternflies can spread quickly into suitable habitat and have the potential to cause significant economic damage to crops and hardwood trees,” said study co-author Tara Trammell, an associated professor of Urban Forestry at the University of Delaware. “Studying potential dispersal mechanisms, such as human transportation, can help us develop management approaches to reduce further spread.”

To simulate spotted lanternfly spread dynamics, the experts used agent-based models incorporating information on life history, habitat suitability, movement, and natural dispersal behaviors. The analysis revealed an overwhelming effect of human-mediated dispersal that supports current observational data and could finally explain the mysterious long-distance jumps across states this insect has made.

Human-mediated dispersal most likely occurs during the period between June and September, when both juvenile and adult lanternflies are present. This is also when mating and egg laying take place. 

“The primary mode of human-mediated dispersal is still to be determined. For example, it could be egg masses laid on vehicles or gravid females hitchhiking on vehicles,” said study lead author Zach Ladin, a supervisory wildlife biologist at the U.S. Fish and Wildlife Service.

“That would be a great follow-up experiment. Future studies could mark and track egg masses on train cars and measure egg mass survival, or mark and track hitchhiking nymphs and adults on tractor trailers.” 

While proving the critical role of human behavior in the wide dispersal of this invasive species is a crucial first step, slowing their spread requires further public education and outreach. If measures to modify human behavior are not urgently taken, the spotted lanternflies will spread quickly to every suitable habitat across North America, with unpredictable economic and ecological impacts.

“The number one suggestion is to follow state recommended guidelines for monitoring vehicles. We suggest people in areas with established spotted lanternfly populations be vigilant when traveling across state lines and follow suggested protocols for monitoring their vehicles when going on long-distance trips,” Ladin advised.

Other measures could include the use of insecticides and traps in late spring, summer, and early fall, and scraping egg masses to prevent the next generation of lanternflies from hatching in winter and early spring.

“Additionally, management and removal of the suite of host trees that spotted lanternflies use to reproduce will help diminish the number of individuals on the landscape, which can lower the likelihood of spotted lanternfly hitchhikers and the establishment in previously unoccupied habitat,” Ladin concluded.

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By Andrei Ionescu, Earth.com Staff Writer

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