Browsing by Subject "Honey bee"
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Item The Effects of Nosema ceranae on honey bee health(2014-10) Goblirsch, Michael JamesHoney bees are arguably the world's most iconic pollinator. The presence of honey bees in our landscapes has long invoked images of vitality, diligence, and cooperation. Unfortunately, the current state of honey bee health and productivity paints a rather different picture for this beneficial insect. The survival of honey bees, as well as the livelihoods of those who benefit from their labor (e.g., beekeepers, growers, and ranchers) is under threat from the culmination of a number of detractors to bee health. Exposure to pesticides, poor forage, mite parasites, and pathogens has resulted in heavy annual death of honey bee colonies in the U.S., Europe, and other parts of the world. Among the suspects thought to contribute to bee decline, the fungal pathogen, Nosema ceranae, is found at high prevalence in both healthy and declining/dead colonies. Since N. ceranae is thought to be a novel pathogen of the European honey bee, Apis mellifera, much remains unknown about its pathology at the individual and colony levels, as well as how infection may interact to form synergisms with other factors thought to be responsible for declining honey bee populations. Here, I review the breadth of research conducted on Nosema infection of honey bees in general. I give particular attention to observations on the detection of infection, cytopathology, viability and infectivity of spores, and incidence and geographic distribution. I rely on what is known about a similar and long-recognized pathogen of A. mellifera, N. apis, for context on the host-parasite relationship of Nosema infection of honey bees. As one part of my dissertation research, I applied background information about the effects of infection on the different castes to show how this may disrupt the social structure of a honey bee colony and contribute to its decline. The level of a honey bee colony or even a whole bee are complicated systems to study intracellular microbes such as Nosema that threaten honey bee health and productivity. Continuous cell lines have been lacking to further our understanding of the pathogenicity of Nosema infection in a simplified environment removed from the confounding effects of other factors such as poor nutrition or pesticides. For the second part of my dissertation research, I addressed this deficiency in honey bee research by developing an in vitro system derived from host cells that could be utilized for observing infection in a simplified environment. Whenever possible, I provide suggestions for future research that could broaden our understanding of this pathogen and ultimately improve honey bee health.Item The influence of mid-continent agricultural land use on the health and survival of commercially managed honey bee (Apis mellifera L.) colonies(2015-02) Smart, MatthewCommercial honey bee colonies were assessed in six apiaries that varied in their land use composition, in the Prairie Pothole Region of North Dakota over three years, 2010-2013. All colonies were transported to California to pollinate almonds each fall and were transported back to North Dakota each spring. The goal of the study was to determine the factors that most influenced, and thus predicted, annual survival of colonies in the different apiaries from summer through the following spring. The factors were grouped into three levels of analysis: 1) land use surrounding the North Dakota summer apiaries, including floral availability and pesticide exposure; 2) colony-level measures of population size, pollen and honey stores, queen status, and presence and prevalence of parasites and diseases; and 3) individual bee-level measures of nutritional physiology and immunity in 7-day old nurse bees collected from healthy colonies within each apiary. Results indicated that the area of uncultivated land (including CRP lands, pasture, grassland, flowering trees and shrubs, fallow land, hayland, and ditches) exerted a significant positive influence on the annual proportion of colonies surviving among apiaries. At the colony level, the amount of brood (pupae) in September and the mean pollen (g) collected per day over the summer correlated with higher annual survival. Higher Varroa destructor mite infestation levels in September were associated with reduced overwinter survival. Individual bee measures positively influencing survival included the expression level of vitellogenin in September and abdominal lipid stores in August. The expression level of lysozyme-2 in September was related to decreased apiary survival. A final, integrated model, incorporating all of the significant factors across the three levels, revealed that all, except Varroa levels, remained significant as predictors of annual colony survival within apiaries. Varroa was actively and effectively controlled by the collaborating beekeeper; thus in this study was not an overall contributor to colony mortality. This is the first study to quantify the impact and importance of pollen nutrition; i.e., "pollen flow" from the level of landscape to the individual-bee, to the health and survivorship of colonies. The most significant predictors of health and survivorship across all three levels of analysis were all related to nutrition - beginning with abundant flowers located overwhelmingly in uncultivated lands. More and/or better forage led to greater honey production and pollen collection which in turn led to greater nutritional stores in individual bees, and an overall decreased immune response. The presence of quality and abundant forage surrounding summering locations support healthy, robust, and most importantly, surviving, colonies of honey bees.Item Land use in the Northern Great Plains region of the U.S. influences the survival and productivity of honey bee colonies(2016) Smart, Matthew D.; Pettis, Jeff S.; Euliss, Ned; Spivak, Marla S.The Northern Great Plains region of the US annually hosts a large portion of commercially managed U.S. honey bee colonies each summer. Changing land use patterns over the last several decades have contributed to declines in the availability of bee forage across the region, and the future sustainability of the region to support honey bee colonies is unclear. We examined the influence of varying land use on the survivorship and productivity of honey bee colonies located in six apiaries within the Northern Great Plains state of North Dakota, an area of intensive agriculture and high density of beekeeping operations. Land use surrounding the apiaries was quantified over three years, 2010–2012, and survival and productivity of honey bee colonies were determined in response to the amount of bee forage land within a 3.2-km radius of each apiary. The area of uncultivated forage land (including pasture, USDA conservation program fields, fallow land, flowering woody plants, grassland, hay land, and roadside ditches) exerted a positive impact on annual apiary survival and honey production. Taxonomic diversity of bee-collected pollen and pesticide residues contained therein varied seasonally among apiaries, but overall were not correlated to large-scale land use patterns or survival and honey production. The predominant flowering plants utilized by honey bee colonies for pollen were volunteer species present in unmanaged (for honey bees), and often ephemeral, lands; thus placing honey bee colonies in a precarious situation for acquiring forage and nutrients over the entire growing season. We discuss the implications for land management, conservation, and beekeeper site selection in the Northern Great Plains to adequately support honey bee colonies and insure long term security for pollinator-dependent crops across the entire country.Item Timing of Mating Flights of Neotropical African and European Honey Bee Queens and Drones (Hymenoptera: Apidae) in Eastern Venezuela(University of Kansas Natural History Museum, 1999) Otis, Gard W.; Taylor, Orley R., Jr.; Spivak, Marla; Winston, Mark L.; Katz, Susan J.; Kukuk, Penelope F.Mating flight characteristics of reproductives of neotropica lAfrican and European honey bees (Apis mellifera L.) were studied in eastern Venezuela. For queens, mean exit times of all flights and midpoints of mating flights differed significantly between the subspecies, with the midpoints of mating flights by European queens occurring an average of 47 min earlier in the afternoon. Queens of the two subspecies did not differ in other aspects of their orientation and mating flights. Flights of European drones also occurred significantly earlier than those of neotropical African drones. Mating flights of queens and drones of the same subspecies were approximately synchronous. These results are sufficient to explain the weak positive assortative mating that has been reported previously.