Browsing by Subject "Pollination"
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Item Episode 25 Adding Flowering Plants to Your Garden to Increase Pollination: What's Killing My Kale?(2019-08-02) Klodd, Annie; Hoidal, Natalie; Weisenhorn, Julie; Hecht, NathanIn episode 25 of What's Killing My Kale, Natalie talked with Extension Educator (horticulture) Julie Weisenhorn, and recently graduated horticulture master's student Nathan Hecht. Both Julie and Nathan have been studying how flowering plants near fruit and vegetable plots impacts pollination and fruit set. While we generally know that adding flowering plants to the landscape is good for pollinators and beneficial insects, we wanted to dig deeper and learn how much of an impact flowering plants can have, how to go about selecting the proper plants, and how the broader landscape impacts results. This is a longer episode, but it's packed with insight and good discussion.Item Floral traits and pollination of Solidago altissima: mechanisms of local adaptation among and within biomes(2013-07) Hafdahl, Claire ElizabethSolidago altissima is an herbaceous, clonal plant that has differentiated into two subspecies in the prairie and forest biomes in Minnesota. The mechanisms that have driven the divergent evolution of these subspecies are not well understood. The evolution of floral traits is influenced by the trade-off between sexual and asexual reproduction. Floral traits can evolve rapidly, and this often occurs in response to interactions with pollinators. I found differences in floral traits between plants from the two biomes, and these differences strongly affected pollinator abundance. Forest plants allocate proportionally more resources to flowering than to vegetative reproduction via rhizomes compared to plants in the prairie. I hypothesize that there is stronger competition among plants for resources in the prairie, where selection favors greater allocation of resources to vegetative reproduction. I also tested the hypotheses that pollinator abundance is influenced by differences among plant genotypes and the genotypes of neighboring plants. I conducted an experiment and found that the number of pollinators on a plant was influenced by the genotype of a plant, but not by the genetic diversity of neighboring plants. I also found that the abundance of neighboring flowers affected pollinator abundance. Plant genotypes varied in floral size, flowering time, and nectar quantity. Floral size of the individual stem had the strongest effect on pollinator abundance. The variation in floral traits among genotypes may be a result of selection to optimize the tradeoff between vegetative growth and flowering, which can vary spatially and temporally.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 Pollination Studies with Stone Fruits(Minnesota Agricultural Experiment Station, 1951-12) Alderman, W. H.; Weir, T. S.Item Source, Fall-Winter 2014(University of Minnesota Extension, 2014) University of Minnesota Extension