Monitoring and Cold Tolerance of the Invasive Spotted Lanternfly, Lycorma Delicatula (Hemiptera: Fulgoridae)
Open Access
- Author:
- Deecher, Elizabeth
- Graduate Program:
- Entomology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 14, 2023
- Committee Members:
- Gary Felton, Program Head/Chair
Julie Marie Urban, Thesis Advisor/Co-Advisor
Michela Centinari, Committee Member
Sara Hermann, Committee Member
Rudolf Johannes Schilder, Committee Member - Keywords:
- Spotted Lanternfly
Lycorma delicatula
Cold Tolerance
Insect Pest Management
Monitoring - Abstract:
- The spotted lanternfly (Lycorma delicatula) (SLF) has been an invasive species in the Eastern United States since 2014. It first established in Berks, Co. Pennsylvania and has been rapidly spreading to other states since. This insect is a phloem feeding planthopper that specifically impacts the grape industry as well as other native hardwoods. Not only has it become a nuisance to homeowners, but it is also an economically important pest. The goal of this thesis is to improve monitoring tool for regions where it persists and could distribute to. This thesis has four chapters; the first chapter is a literature review to focus on the current research and knowledge of SLF since its arrival in the United States. The last three chapters describe our research experiments on SLF management, monitoring, and biology. The second chapter of this thesis is a three-year study at Green Hills Preserve in Mohnton, Pennsylvania using circle traps on different host species to determine the best deployment strategies for capturing SLF throughout the season. Using this monitoring method, we were able to better understand population presence, relative abundance, seasonal activity, and multi-year trends of SLF in an area near where the infestation first began. Our results showed that what is considered in practice to be the ideal host species to deploy traps on, A. altissima, did not significantly out-perform other tree species, as other species (e.g., J. nigra) can also yield strong capture. Traps are most effective when they are put up before May and taken down at the end of November. In 2021, a strong decline in the population followed by a spike the following year was observed. Overall, circle traps are most effective in areas with high SLF populations, though similar tools have been successful in residential areas where there are high numbers an individual trees. The third chapter of this thesis reports results of experiments on first instar cold tolerance of this species. Laboratory studies were designed to investigate four different cold tolerance factors of SLF first instar nymphs to aid in determining where SLF can distribute and establish. The four factors included critical thermal minimum (CTmin), chill coma recovery time (CCRT), lower lethal temperature (LLT), and lethal time at low temperature (LLt). For first instar nymphs, the CTmin ranged from 7.3 to 7.8 C, with a mean CTmin of 7.666 ± 0.017 C (mean ± SEM). The CCRT ranged from 1 to 621 seconds, with a mean CCRT of 114 ± 18 seconds (mean ± SE). The LLT was near -7.5 C for 100% death, while LLt is predicted to occur around 950 minutes at -2.5 C for 100% death based on results using logistic regression modeling. Overall, this study provides first insights of cold tolerance for SLF and helps to develop and inform models for understanding limits for first instar survival. The fourth chapter of this thesis investigates evidence concerning whether and potentially how SLF generates heat. There is a crucial need for improved monitoring tool for SLF in areas of infestation as well as areas of potential establishment. It has been demonstrated that SLF are able to be detected using infrared cameras, suggesting that the insect seems to be generating heat. Yet, evidence concerning whether SLF is generating heat is limited, and if it is, potential explanations of how and under what conditions SLF does so remain to be explored. In this study, adult SLF body temperatures are taken throughout the day, along with weather data, body mass, and activity in order to gather more baseline evidence concerning whether SLF may be generating heat. This information sheds light on this potentially unusual aspect of SLF’s basic biology, in order to inform further studies of possible endothermy, which in turn, could lead to the potential development of thermal monitoring for SLF. Findings from this thesis help to improve monitoring tool for the invasive SLF in regions where it persists and could distribute to. Trends from the three-year trapping study demonstrate host species can vary and still yield capture. The firsthand information on first instar cold tolerance of this species as well as investigating evidence into whether and potentially how SLF generates heat gives a better understanding of SLF’s basic biology and the ability to determine better prediction of SLF’s distribution, establishment, and potential control and monitoring methods. Altogether, this information can aid in the use of monitoring tools in infested areas as well as areas that are at risk of establishment.