Sizing up spotted lanternfly nymphs for instar determination and growth allometry

Area of Science:

• Entomology
• Invasive Species Biology
• Pest Management

Background:

• The spotted lanternfly (SLF) (Lycorma delicatula) is a significant invasive pest in the U.S. and South Korea.
• Accurate staging of SLF nymphal instars is challenging due to similar morphology in early stages.
• Understanding SLF life stages is critical for developing effective control strategies.

Purpose of the Study:

• To develop reliable methods for staging SLF nymphs using body mass and length.
• To analyze the growth patterns and morphological scaling of SLF nymphs across instars.
• To compare regional variations in SLF nymphal metrics for accurate staging.

Main Methods:

• Collected body mass and length data for SLF nymphs over two growing seasons.
• Applied clustering methods to differentiate nymphal instars based on mass and length.
• Analyzed allometric scaling of SLF nymph body mass, footpad area, tarsal claws, and mouthparts.

Main Results:

• Body mass and length data allowed for distinct clustering of 1st-3rd instar SLF nymphs.
• Length ranges for 2nd-4th instars showed year-to-year agreement but differed from previous studies.
• SLF nymph body mass scaled with length, with footpad area proportional to weight and tarsal claws showing positive allometry.

Conclusions:

• Body mass and length provide a robust method for staging SLF nymphs within a growing season.
• Regional data are essential for accurate SLF nymph staging due to variations in growth metrics.
• Understanding SLF nymphal growth and scaling aids in predicting their invasive potential and refining control measures.