Community forests are of critical importance to the ecological integrity of the urban landscape and provide millions of dollars in ecosystem services annually to people like you and me. In an era of increasing globalization, introduced species of insects pose a threat to urban forests, where drought stress and a changing climate regime make trees more vulnerable to attack. My current research focuses on Xanthogaleruca luteola (the Elm Leaf Beetle) and Orchestes steppensis (the Elm Flea Weevil), two invasive beetles of elm trees in urban forests. My research seeks to uncover the underlying factors that facilitate insect outbreaks and resulting damage to urban trees using these two insects as the study system. By elucidating the mechanisms underlying damage by invasive insects across a patchwork of varied urban sites, this research will facilitate preventative management that directly addresses the causes of damaging insect outbreaks and prioritizes sites that exhibit risk factors. It is also my hope results can be applied to both current and future invaders of the urban forest in an era where globalization and climate change make them particularly vulnerable to attack.

Impervious Surface & Urban Heat

Dominance of impervious surface is an important factor in shaping microclimate across a patchwork of varied urban sites. As urban areas develop and vegetation is replaced with surfaces that are impervious to water, the heat retention and high albedo properties of these surfaces induce warming. This phenomenon is commonly known as the urban heat island. Impervious surface and resulting temperature increases can influence insect populations through a variety of underlying mechanisms. My research evaluates relationships between impervious surface, canopy temperature, and insect abundance and damage.

Top-Down Control & Vegetative Complexity

Natural enemies are important in regulating populations of herbivorous arthropods. However, top-down control of herbivores is particularly lacking in patchy and isolated habitats, which are especially common in urban areas. One feature of the urban environment that is known to impact natural enemy abundance for both predators and parasitoids is habitat complexity and vegetative structure. My research examines the role of natural enemies in limiting populations of Elm Leaf Beetle and Elm Flea Weevil, as well as the role of vegetative structural complexity in supporting natural enemy populations.

Built Structures & Overwintering Survival

Many insects are not freeze tolerant, even during diapause. In urban environments, built structures contribute to insect overwintering survival in two ways. Buildings increase survival directly as insects migrate into buildings to overwinter. They also increase survival indirectly by changing the surrounding microclimate, making it warmer and acting as a windbreak. My research explores the relationship between proximity to built structures and density and damage of the Elm Leaf Beetle and Elm Flea Weevil.

Host Availability

Availability of a preferred host is critical to herbivore colonization success, their potential to reach outbreak levels, and their ability to cause damage. Urban areas that are dominated by a single host tree make ideal conditions for the establishment, damage and spread of non-native insects. Such was the case with American Elm and the wood boring beetles that vector Dutch Elm Disease, and this is the looming fate of Ash trees with the introduction of Emerald Ash Borer in North America. Host availability is not uniform across the urban landscape and is highly variable between different urban sites; these differences are often correlated to herbivore abundance. My research evaluates the relationship between host density and insect density and defoliation.

Undergraduate Research: Crop Pests & Biocontrol

My undergraduate research focused on the Crucifer Flea Beetle, Phyllotreta cruciferae (Chrysomelidae), a major pest of Canola and other Brassica crops. This research sought to establish a novel molecular protocol for identifying biological control agents for P. cruciferae. This work was conducted as part of the Sharanowski Lab at the University of Central Florida in partnership with the Costamagna Lab at the University of Manitoba.

Explore the oral presentation I gave on this project at the 2018 Southeastern Branch meeting of the Entomological Society of America.

ESA 2018 Jacqueline Meyer.pptx