Observations of adult spotted lanternfly (Hemiptera: Fulgoridae) behavior on <i>Ailanthus altissima</i>

Abstract Lycorma delicatula White, commonly known as spotted lanternfly, is an invasive phloem-feeding insect which was first detected in the United States in 2014. It is now present in 19 states and is a serious pest in specialty crops (eg cultivated vineyards) and a nuisance pest in residential areas. Despite ongoing studies into methods for monitoring and biosurveillance, an effective attractant has not been identified. In this study, we recorded adult L. delicatula on the trunks of mature Ailanthus altissima (Mill.) from late August to mid-November in 2020, 2021, and 2023. We observed adults on mature trees from the ground to 2 m above every 2 wk between 7 AM and 11 AM, and recorded every aggregation, individual, and pair of L. delicatula present. For each aggregation, the number of adults (aggregation size), sex of each adult, aggregation area, distance from ground level, and notable behaviors were recorded (feeding, resting, walking up or down, courtship and mating). Our data on aggregation size, individuals, and male–female pairs found no evidence of a relationship with day of year beginning in September. However, male–female sex ratio approaches 1 in late September; reproductive behaviors occur around the same sex ratio. Feeding was the most frequently observed behavior within and between all years and continued throughout the mating and oviposition period. Our data indicate targeting the period when courtship and mating begin may provide opportunities for identification of novel olfactory or vibroacoustic stimuli for monitoring or biosurveillance.