Spotted Lanternfly

A Planthopper That Borrows Its Poison

The spotted lanternfly, Lycorma delicatula, is neither a fly nor a moth. The Pennsylvania Department of Agriculture calls it an invasive planthopper. Animal Diversity Web warns that adults can be confused for moths. It feeds with piercing-sucking mouthparts that work like a tiny straw.

Its best trick is chemical. Third-stage nymphs are black with white spots, but fourth-stage nymphs, the final nymph stage, are red with white spots. Adults hide back wings that are bright red near the body and show only in flight. A 2018 study linked the switch to red with the insect narrowing its diet mainly to the tree of heaven, an invasive tree defended by chemicals called quassinoids. The lanternflies keep one of them, ailanthone, in their bodies. Bright colours on a distasteful animal warn predators off, a strategy called aposematism.

Borrowed warning In taste trials, birds shunned lanternflies gathered from tree of heaven but not ones gathered from other host plants.

Small Body, Big Jumps

Adult females are 24 to 27 mm long and males are 21 to 22 mm, according to Animal Diversity Web. In a lab study in which nymphs were reared on tree of heaven, newly moulted adult males averaged 0.120 g and females 0.175 g.

The nymphs are acrobats. High-speed video of nymphs jumping in a lab showed take-off speeds of 2.7 to 3.4 metres per second and accelerations of 800 to 1,000 metres per second squared, from fast hind-leg extensions. They spun in mid-air at 5 to 45 turns per second, yet landed successfully in 58.9 percent of trials.

A second study dropped nymphs and filmed them landing. Nymphs land at varying angles, then flip upright as they bounce, using body rotations, foot adhesion and leg motions. The authors say they take advantage of near-total energy loss on impact.

One Generation a Year

Animal Diversity Web lists the species as univoltine, meaning one generation a year. Females lay eggs from August to early November, and the eggs overwinter. In a Pennsylvania study from 2016 to 2017, egg masses held up to 192 eggs, though 91.8 percent held under 50. Eggs hatched between 2 May and 5 June, and the adult stage ran from 24 July to 15 November, 114 days. Adults spent about two months feeding, then laid eggs in early October.

An Invader That Hitches a Ride

The lanternfly is native to China, Taiwan, India and Vietnam, and in 2020 Animal Diversity Web listed it as invasive in Korea, Japan and the United States. It was first discovered in Berks County, Pennsylvania, in 2014. California’s agriculture department says it can walk, jump or fly short distances, but its long-distance spread is helped by people who move infested items. It lays eggs on almost any surface, including vehicles and outdoor equipment.

Penn State reported in 2022 that it feeds on more than 100 plant species. Recent research suggests it rarely kills them, and it is not known to bite or sting. Its sugary waste, called honeydew, feeds sooty mold. Nature also pushes back: in a 2019 study, two native fungi caused a local outbreak of lanternflies in the eastern United States to collapse.