Life Sciences Commons^™

Monarch Butterflies: Rearing Methodologies And The Impact Of Fungicide And Insecticide Exposures, Matthew Greiner

Department of Entomology: Dissertations, Theses, and Student Research

The North American migratory monarch butterfly, Danaus plexippus L., populations has experienced a ca. 90% decline over the past two decades. The decline is attributed to climate change, loss and degradation of overwintering habitat, and the loss of milkweed plants in the midwestern United States. The remaining milkweed stands often occur close to agricultural fields, and efforts to establish additional milkweed on the landscape focus on agricultural systems. However, milkweed plants near agricultural fields are likely exposed to pesticides that could adversely impact monarch caterpillars. Effective management of milkweed habitat supporting monarch caterpillars requires knowledge about the toxicological impacts of …

Toxicology Of Chemical Stress To Monarch Butterflies (Danaus Plexippus L.), Annie Krueger

Department of Entomology: Dissertations, Theses, and Student Research

Monarch butterfly (Danaus plexippus L.) population declines have caught the attention of the country and prompted nationwide conservation initiatives. The United States Fish and Wildlife Service has identified insecticide exposure and loss of milkweed (Asclepias spp.) reproductive habitat as primary threats to the monarch. In the Midwestern US, milkweed largely occurs around cropland borders where there may be a spatial and temporal overlap of monarch larvae, insecticide usage, and fertilizer applications. In this study, the acute toxicity and sub-lethal effects on growth and diet consumption of two commonly used pyrethroid insecticides, bifenthrin and beta-cyfluthrin, were characterized …

Surveillance Of Culex And Aedes Mosquitoes In Lincoln, Lancaster County, Nebraska, William Noundou

Department of Entomology: Dissertations, Theses, and Student Research

In 2018, West Nile virus (WNV) was identified as the leading cause of mosquito-borne disease in the continental United States. In response to this very serious problem, the Lincoln-Lancaster County Public Health Department (LLCHD) reinforced their mosquito surveillance program, which constitutes one of the best available tools to fight against this serious threat to human health. The objectives of this study were to 1) expand knowledge of the activity and relative abundance of mosquito communities in understudied areas and 2) evaluate differences in mosquito communities by urban and rural location, especially focusing on known vector species. A total of 6 …

Ecological Risks Of The Conventional Insecticide/Fungicide Seed Treatment Mixture Of Thiamethoxam And Mefenoxam In Soybean On Beneficial Insects, Carolina Camargo

Department of Entomology: Dissertations, Theses, and Student Research

The impact of neonicotinoid seed treatments on beneficial insects has been a controversial topic during the last years. While neonicotinoids are usually used as mixtures with systemic fungicides, few studies have examined the impact of the mixtures on beneficial insects. Pesticide mixtures can have synergistic, additive, or antagonistic effects on the toxicity of neonicotinoids on non-target species.

Thiamethoxam with mefenoxam is the most used neonicotinoid insecticide/fungicide mixture applied to soybean. Based on the systemic nature of thiamethoxam and mefenoxam, residues of this insecticide/fungicide mixture can be present in soybean vegetative and floral tissue with potential impacts to beneficial insects. This …

Toxic And Repellent Effects Of Pyrethroids Used In Orchards On The Honey Bee, Apis Mellifera L. (Hymenoptera: Apidae), Erin M. Ingram

Department of Entomology: Dissertations, Theses, and Student Research

Managed honey bee colonies provide valuable pollination services and are rented by fruit orchards to improve fruit quality and yield. The placement of colonies in this agricultural setting increases the possibility of exposure to pyrethroids used for broad-spectrum pest control in orchards. Although highly toxic to bees, pyrethroids are believed to pose a relatively low hazard due to their low application rates in the field as well as their contact repellent properties. Previous studies have noted a decrease in foraging visits following pyrethroid application possibly preventing bees from acquiring a lethal dose in the field.

This research quantified behaviors associated …