THE ANIMAL FILES

Spotted lanternfly

Lycorma delicatula

A plant-feeding hopper leaves sugar behind.

Spotted lanternflies use piercing mouthparts to draw sap rather than chewing leaves or fruit. Sugary honeydew connects feeding with sooty mould growth on surfaces below. The insect also changes dramatically from spotted wingless nymph to winged adult.[1]

Follow the evidence ↓
Spotted lanternfly
Image: Rhododendrites · Commons · CC BY-SA 4.0
Pierce, do not chew
Mouthparts reach plant sap.[1]
The honeydew pathway
Sugary waste coats surfaces below.[1]
Growing into wings
Nymphs are wingless.[1]

Pierce, do not chew

The insect pierces tissue to feed from phloem. Tree of heaven is an important host, but other plants are used too and associations change with stage. A host record does not mean leaves were eaten as chunks.[1]

The honeydew pathway

Excess sugary fluid falls onto leaves and stems. Mould can grow on the coating and reduce light reaching plant surfaces. Ants, bees and wasps can also be attracted, so some consequences of feeding occur away from the exact puncture site.[1]

Growing into wings

Young nymphs are dark with white spots; later stages add red patches before the adult's spotted forewings and bright hindwings develop. Nymphs hop and crawl between plants. Adult and juvenile photographs can therefore show very different forms of the same species.[1]

A COMMON MIX-UP

Does it damage plants mainly by eating holes in leaves?

No. It feeds by piercing and sap sucking; honeydew and mould add indirect effects.[1]

TRY A LITTLE REASONING

How could a leaf below the feeding insect be affected?

Reveal the explanation

Honeydew can land on it and support mould, reducing available light without a feeding puncture there.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Spotted lanternfly (cited revision)
  2. NCBI Taxonomy — Lycorma delicatula

Last fact check:

One discovery leads to another

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