Flight Dispersal Capabilities of Female Spotted Lanternflies ( Lycorma delicatula ) Related to Size and Mating Status

The spotted lanternfly , Lycorma delicatula (White), is an orchard and forest pest native to China. Since its detection in Pennsylvania, USA in 2014, it has spread to other states as well. We conducted experiments to determine the flight capabilities of unmated vs. mated L. delicatula females to assess the relative threat posed by each type with regard to expanding the infestation area through their natural flight behaviors. Females were collected from mating pairs, captured on plants, and netted during flights averaging 24 m, then dissected and examined for male spermatophores, a diagnostic character for determining mating status. The weight, amount of yellow area on the abdomen, wing area, and body length and abdominal width was recorded from these females. Sedentary females on plants were selectively collected for their large and swollen abdomen. They were capable of only flying ~4 m when forcibly launched and were significantly heavier than the in-flight-captured females. More than 93% of these large, sedentary females had mated whereas <5% of the flight-captured females had mated. Spontaneously flying females weighed significantly less, and had significantly smaller and less yellowed abdomens than sedentary plant-captured females. We conclude that nearly all the observed spontaneously flying L. delicatula females were unmated and therefore pose a lower threat to spread the infestation than previously thought. We also hypothesize that these thinner, spontaneously flying females embark on these 10–50-m-long flights because they need to find new trees on which to feed to complete their egg maturation in order to oviposit successfully.