Doctoral Dissertations

Orcid ID

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Entomology, Plant Pathology and Nematology

Major Professor

Jerome Grant

Committee Members

Monica Papeş, Scott Stewart, Liem Tran, Gregory Wiggins, Gregory Wiggins


Biological invasions have put growing threats on ecosystems and human society, exacerbate effects of climate change, and cause economic loss globally. Modeling invasion risk and processes of pest species are essential for early prediction and warning and are increasingly used for detection and control of invasion outbreaks. Kudzu bug, Megacopta cribraria (F.), native to Asia, has become a pest in both agricultural and urban areas since its initial discovery in the United States (U.S.) in 2009. As the establishment of kudzu bug is relatively new in the U.S., its potential invasion risk in the Americas, spread dynamics, and factors that may impact its spread, are not well understood. Thus, this research was intended to address these gaps. This project also evaluated methods that can better estimate invasion risk and dynamics. Findings of this research can guide management of kudzu bug and also provide guidance on approaches to estimate invasion risk and dynamics. High invasion risk of kudzu bug was predicted by species distribution models (SDMs) in eastern U.S., Central America, and central South America. Kudzu bugs generally inhabit warm (annual mean temperature around 15℃) and humid (annual mean precipitation around 1300mm) regions. Due to non-adaptive niche shift, kudzu bugs occupied different environmental conditions between the native and invaded ranges. Using kudzu bug as a case study and seven SDMs, non-adaptive niche shift does not necessarily challenge transferability of SDMs. Additionally, the spatial range where PAs are extracted can significantly impact both interpolation and transferability of SDMs. Geopolitical-unit invasion record is capable of estimating invasion dynamics. Boundary displacement methods have the best estimations for both overall rate and spread dynamics. However, for spread without a clear infestation outline, area-based regression methods can be good alternatives for estimating invasion dynamics. The spread rate of kudzu bug was 76 km/year during 2010-2016, however, the rate varied largely among different regions (45 - 144 km/year). The availability of host plants seemed to play an important role on the spread of kudzu bug in the southern region, while the low temperature in January was the most important factor in the northern region.

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