Performing Department
Entomology
Non Technical Summary
The invasive spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) is an economically important invasive insect pest that is rapidly spreading in the eastern US. It poses a significant economic threat to many woody tree species in MD including native and economically-important trees and woody plants. Nymphs and adults cause substantial damage by sucking phloem sap and subsequently reducing photosynthesis, causing weeping wounds, and creating conditions for sooty mold. Lanternfly nymphs switch host plants during their development. However, little is known about the relationship between the lanternfly and its tree hosts. Information is particularly needed regarding the association between the lanternfly mouthparts and its feeding behavior. Our objectives include (1) investigating how the lanternfly utilizes its host plants by assessing its stylet morphology (the piercing-sucking mouthpart which allows it to penetrate bark), (2) predicting potential tree host-associations at each developmental stage, and (3) providing information to forest managers for effective monitoring of the lanternfly on tree hosts throughout the season. We expect the lanternfly mouthparts to be highly adapted to various host trees and to undergo structural changes throughout the lanternfly development. This information will be used to help predict lanternfly dispersal to new host trees and prevent rapid infestation of trees.
Animal Health Component
0%
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
The invasive spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) is an economically important invasive insect pest that is rapidly spreading in the eastern US. It poses a significant economic threat to many woody tree species in MD including native and economically-important trees and woody plants. Nymphs and adults cause substantial damage by sucking phloem sap and subsequently reducing photosynthesis, causing weeping wounds, and creating conditions for sooty mold. Lanternfly nymphs switch host plants during their development. However, little is known about the relationship between the lanternfly and its tree hosts. Information is particularly needed regarding the association between the lanternfly mouthparts and its feeding behavior.To address these issues, in this project we focus on exploring and predicting lanternfly host plant usage by assessing changes in its stylet morphology at each developmental stage.Our specific objectives are:Objective 1. To assess the changes in morphology and morphometric characteristics of L. delicatula stylets during the lanternfly development and their potential effect on tree host plants.Objective 2. To estimate the depth of the lanternfly stylet penetration and stylet movement within plant tissues and predict potential tree host-associations at each developmental stage of the lanternfly.Objective 3. To provide information about the lanternfly stylet morphology and susceptible host trees to forest managers and other stakeholders - to help them effectively scout and monitor the lanternfly nymphs and adults on potential tree host plants.We expect the lanternfly mouthparts to be highly adapted to various host trees and to undergo structural changes throughout the lanternfly development. This information will be used to help predict lanternfly dispersal to new host trees and prevent rapid infestation of trees.
Project Methods
This one-year project will be conducted at the Department of Entomology, University of Maryland, and will include a laboratory study, as well as several collection trips to Pennsylvania (or in Maryland once the spotted lanternfly invades Maryland). During this year we will (a) perform a morphological analysis of the lanternfly mouthparts based on measurements and observations of stylet morphology at each insect developmental stage (Objective 1); and (b) propose potential tree host-associations at each developmental stage based on established characteristics of tree bark (Objective 2). Based on these findings we will then provide information to forest managers for effective scouting and monitoring of the spotted lanternfly throughout the season (Objective 3).Our specific methods for each objective include:Objective 1- assess changes in morphology and morphometric characteristics of L. delicatula stylets. Developing a step-by-step protocol for insect dissection, isolating stylets, and tissue preparation for morphological analysis. Individual insects at each developmental stage will then be placed in a Petri dish with a standard saline. Under the dissecting microscope the stylets will be isolated, and then transferred to a microscope slide (for light microscopy) and/or fixation solution (for scanning electron microscopy). Using resources for light and scanning electron microscopy located in the Department of Entomology and the Laboratory for Biological Ultrastructure, the morphology of the stylets will be investigated, and all the morphological structures will be photographed. These photographs will serve as a reference for searching same morphological structures at each developmental stage.Identifying morphometric characteristics used in a comparative analysis of the stylet morphology at each developmental stage. We will specifically focus on (a) determining the length of the stylet, and (b) describing the stylet morphology (for the first time) for each developmental stage of the lanternfly. Both the stylet length and stylet morphology will allow us to pinpoint a type of host plants the lanternfly is associated with at each developmental stage; specifically, we will be able to determine relative bark thickness and plant tissue density. Based on the results from this morphological analysis we will identify a number of morphometric characteristics which will be used in the comparative analysis of the stylet morphology at each developmental stage.Morphometric comparative analysis of the lanternfly stylets among developmental stages. For this comparative analysis, the lanternfly nymphs and adults will be collected from different host plants at several field sites in PA during summer 2019. We will collect specimens at five locations in PA from up to 10 different host trees creating a range of host plant sizes and bark structure. We are especially interested in comparing early nymphs which are broad generalists and have the potential to impact a wide range of trees, late nymphs with narrower host plant range, and adults which tend to attack only a few preferred host plants. Difference in the stylet length and other characteristics among nymphs and adults may indicate the difference in distance from the bark surface to the phloem tissue of the lanternfly host trees; which, in turn, may reflect the pattern of switching host trees during the lanternfly development.Objective 2 - estimate stylet penetration and movement:Morphometric comparative analysis of the lanternfly stylet penetration and investigating plant tissue samples. We will set up a series of host preference feeding experiments which will be conducted either in University of Maryland environmental chambers (if the lanternfly invades MD before Summer 2019) or at field sites in PA (the experimental sites and potential collaborators in PA will be determined during Spring 2019). For these feeding experiments, lanternfly nymphs and adults will be allowed to feed on different host trees. Following techniques used by Freeman et al. (2001), insects and plant tissues from the feeding site will be frozen with dry ice cooled 2,2-dimethoxypropane. Using rapid methods of killing and fixing adults and nymphs as they feed on host branches and leaves will allow us to obtain more accurate measurements of stylet lengths and the mechanism of stylet insertion, before the insects could retract their stylets. We will collect and fix at least 10 individuals at each developmental stage. Based on the comparative analysis of stylet length, we will estimate the depth of stylet penetration in various host plants which the lanternfly needs to overcome to reach the phloem. We will also identify probe sites in plant tissue samples (leaves and branches) and examine them under light and scanning electron microscopy. Following Freeman et al. (2001), we will determine whether the lanternfly probed and fed on host plant or abandoned the feeding site after probing. Based on these results as well as known characteristics of bark from woody plants, we will then propose a range of host trees which are most susceptible to the lanternfly feeding at each developmental stage of the pest.Objective 3 - provide information to forest managers and other stakeholders:Develop recommendations and share intermediate results at forestry meetings. During this project, all the findings will be distributed to forest managers, researchers, regional specialists, growers, and other MD stakeholders through extension events and publications. We will especially focus on sharing the information about the ecology and sustainable management of the lanternfly, such as: (1) the lanternfly life cycle; (2) the lanternfly host range; (3) tree species which are most susceptible to infestation by the lanternfly at each developmental stage; and (4) offer recommendations for effective scouting and monitoring of the lanternfly throughout the year.