The western honey bee, Apis mellifera, provide invaluable economic and ecological services while simultaneously facing stressors that may compromise their health. For example, agricultural landscapes, such as a row crop system, are necessary for our food production, but they may cause poor nutrition in bees from a lack of available nectar and pollen. Row crops are largely wind or self-pollinated, and while previous studies have focused on the impact of bees to row crops, fewer studies have examined the reciprocal relationship of the row crops on honey bees. Here we investigated the foraging dynamics of honey bees in a row crop environment. We decoded, mapped, and analyzed 3460 waggle dances, which communicate the location of where bees collected food, for two full foraging seasons (April – October, 2018-2019), and concurrently collected pollen from returning foragers. We found that bees foraged mostly locally (< 2 km) throughout the season. The shortest communicated median distances (0.48 and 0.32 km), indicating abundant food availability, occurred in July in both years, which was when our row crops were in full bloom. We determined, by plotting and analyzing the communicated locations, that most mid-summer foraging was in row crops, with at least 40% of honey bee recruitment dances indicating either cotton or soybean fields. Bees also largely foraged for nectar when visiting row crop fields, only returning to the hive with Glycine spp. pollen, and foraging on nearby trees and weeds for pollen. Foragers were exposed to thirty-five different pesticides throughout the foraging season, based on pesticide residues in collected pollen. Overall, row crop fields are contributing a surprising majority of mid-summer forage to honey bee hives and suggests that similar agricultural landscapes may also provide abundant, mid-summer forage opportunities for honey bees, however, at the risk of pesticide exposure. / Master of Science in Life Sciences / Declines in the number of honey bee hives have been observed in the United States and western Europe throughout the last century, driven by environmental stressors such as poor nutrition caused by anthropogenic landscape change and pesticide exposure. Agricultural landscapes, for example, contain monocultures and often necessitate pesticide use, which may be detrimental to bee health. Because of these effects, it is necessary to understand how honey bees forage in these systems and what potential health risks they face. We investigated honey bees foraging dynamics in a row crop environment, observing honey bee waggle dance recruitment behavior and gathering forager-collected pollen to better understand when, where, and what honey bees forage on throughout the season (April – October). We found that bees largely foraged near the hive throughout the season, indicating that sufficient resources were available, particularly in July when crops were in full bloom. During full bloom bees considerably foraged in cotton and soybean fields. We found that bees collected minimal row crop pollen, apart from soybean pollen, largely foraging on trees and flowering weeds for pollen. Through pollen foraging bees were exposed to thirty-five pesticides, ranging in toxicity and mode of action. Overall, honey bees foraging in a row crop system foraged substantially in row crop fields during the mid-summer. Row crops systems may be able to provide abundant forage during the mid-summer, but could come at the risk of exposure to pesticides.

Neonicotinoid seed treatments are widely used and highly effective against early season insect pests of all row crops throughout the Mid-South region of the United States. An analysis was performed to determine the value of neonicotinoid seed treatments across multiple trials in soybean, Glycine max L.; corn, Zea mays L.; cotton, Gossypium hirsutum L.; and sorghum, Sorghum bicolor L. production systems across the mid-southern region. Neonicotinoid seed treatments provided significant yield and economic increases when utilized the majority of the time. A second experiment was performed to determine the value of various insecticide classes when utilized in an overall systems approach when managing cotton insect pest in the Delta and Hills region of Mississippi. When all classes of insecticides were used in rotation, significant yield and economic benefits were observed in the Delta Region compared to treatment scenarios where some insecticide classes were omitted.

A study was conducted to determine what impact high white-tailed deer (Odocoileus virginianus) densities were having on the native grasslands of a tallgrass: aspen forest tract embedded within an agro-urban setting. Due to excessive spring moisture, row-crops were unavailable the first year. Using microhistological fecal analysis to determine dietary composition, deer were assessed to be placing the site’s favoured native plant species at risk of extirpation. Measuring woody stem abundance and height along and near the prairie: forest ecotone, deer were found to restructure woody growth but not directly influence encroachment rates. Indirectly, however, deer facilitated forest encroachment and prairie degradation through seed dispersal, nitrogen deposition, gap-dynamics, and trampling. Comparing dietary composition to nutritional data, deer grazed to maximize fitness, selecting foods high in IVDMD, minimizing energy expenditure, and optimizing CP. High crop CP was offset by intensively grazing particular native plants. ADF was an effective nutritional marker, not AIA.

A study was conducted to determine what impact high white-tailed deer (Odocoileus virginianus) densities were having on the native grasslands of a tallgrass: aspen forest tract embedded within an agro-urban setting. Due to excessive spring moisture, row-crops were unavailable the first year. Using microhistological fecal analysis to determine dietary composition, deer were assessed to be placing the site’s favoured native plant species at risk of extirpation. Measuring woody stem abundance and height along and near the prairie: forest ecotone, deer were found to restructure woody growth but not directly influence encroachment rates. Indirectly, however, deer facilitated forest encroachment and prairie degradation through seed dispersal, nitrogen deposition, gap-dynamics, and trampling. Comparing dietary composition to nutritional data, deer grazed to maximize fitness, selecting foods high in IVDMD, minimizing energy expenditure, and optimizing CP. High crop CP was offset by intensively grazing particular native plants. ADF was an effective nutritional marker, not AIA.

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