Spotted lanternfly honeydew: a resource to Hymenoptera communities

Background/Question/Methods

Spotted lanternfly (SLF), Lycorma delicatula (White) (Hemiptera: Fulgoridae) is an invasive pest that was first detected in the United States in 2014. SLF has drawn a lot of attention for its potential to induce damage to crops like grapes via feeding, and a key side effect of SLF feeding is the production and excretion of carbohydrate-rich honeydew. This honeydew lands below the feeding spot, leading to the aggregation of otherwise unavailable sugars. These sugars become available where they previously would not have been found in such large quantities, potentially creating a resource to other organisms, but given its nascent introduction, the foraging effects of SLF honeydew production in the new invaded range are unclear. Here we document Hymenoptera feeding on SLF honeydew and address the following question: what factors cause spatial variation in the Hymenoptera communities feeding on SLF honeydew? We surveyed Hymenoptera communities around SLF-infested trees at 44 sites throughout the invaded range pairing visual observations with SLF trapping. The vegetation around each study tree was surveyed along with a timed honeydew droplet count.

Results/Conclusions

In addressing this question, we document the biotic interactions in Hymenoptera that are linked to SLF honeydew production and present evidence that SLF honeydew provides a service to native Hymenoptera. With this research, we identified over 15 species of Hymenoptera feeding on SLF honeydew, many of which are native to the region. Spatial and temporal variation in honeydew production and Hymenoptera community foraging was found during this observational study. Biotic interactions peaked during late summer when the largest amounts of honeydew near tree trunks was available. Competition for honeydew and oozing sap from SLF feeding holes was observed between multiple Hymenoptera, while some Hymenoptera also disrupted SLF from their feeding and thereafter took over the feeding hole. In addition to the biotic interactions, environmental factors influencing spatial variation were analyzed focusing on the vegetation in the vicinity of study trees. This study is important in documenting novel ecological interactions due to an invasive species and provides insight into potential effects and changes that could occur in the system as a result of this subsidy.