Browsing by Subject "pollinator"

Now showing 1 - 3 of 3
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    Broadening the Definition of the Taxonomic Domain of Applicability of an Adverse Outcome Pathway Through Bioinformatics Approaches
    (2022-08) Jensen, Marissa
    For the majority of developed adverse outcome pathways (AOPs), the taxonomic domain of applicability (tDOA) is typically narrowly defined with a single, or a handful of species. Defining the tDOA of an AOP is critical for use in regulatory decision-making, particularly when considering protection of untested species. Structural and functional conservation are two elements that can be considered when defining the tDOA. Publicly accessible bioinformatics approaches, such as the Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool, take advantage of existing and growing databases of protein sequence and structural information to provide lines of evidence toward structural conservation of key events (KEs) and key event relationships (KERs) of an AOP. It is anticipated that SeqAPASS results could readily be combined with data derived from empirical toxicity studies to provide evidence of both structural and functional conservation, which can be used to define the tDOA for KEs, KERs, and AOPs. Such data could be incorporated in the AOP-Wiki as lines of evidence towards biological plausibility for the tDOA. Here, a case study describing the process of using bioinformatics to define the tDOA of an AOP is presented using an AOP linking the activation of the nicotinic acetylcholine receptor to colony death/failure in Apis mellifera. While the AOP was developed to gain a particular biological understanding relative to Apis mellifera health, applicability to other Apis bees, as well as non-Apis bees, has yet to be defined. This work demonstrates how bioinformatics can be utilized to rapidly take advantage of existing protein sequence and structural knowledge to enhance and inform the tDOA of KEs, KERs, and AOPs, focusing on providing evidence of structural conservation across species.
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    Influence Of Flower Strips On Insect Pollinator Recruitment And Crop Yield In Day-Neutral Strawberry Production
    (2019-05) Hecht, Nathan
    Around 35% of our food comes from pollinator-dependent crops, especially many fruit crops. In light of emerging threats to the honey bee industry, recent research has highlighted the importance of wild insect pollination services in agroecosystems. Pollinator “farmscaping” practices, which provide habitat and floral resources for wild insect pollinators on farms over space and time, are being investigated for horticultural crops. However, there is relatively little research directly linking pollinator farmscaping practices to crop yields, especially considering the wide variation in pollination requirements between crop species. Strawberries (Fragaria x ananassa), though self-fertile, appear to produce higher quality fruit when flowers are more thoroughly fertilized by pollinating insects. Ensuring effective pollination services for strawberry crops may be even more beneficial in day-neutral cultivars, which flower and fruit continuously throughout the growing season, as opposed to the short-day (June-bearing) cultivars commonly grown in the US Midwest. While some research has shown increased pollinator abundance in strawberry fields adjacent to annual wildflower strips, there is less research on direct benefits to strawberry production, particularly for day-neutral strawberries. In addition, most flower strip research focuses on diverse wildflower strips, despite evidence that bees may benefit more from flower plantings with clumps of single species rather than heterogeneous mixtures. This research investigates the potential of planting an attractive annual flower strip as a “magnet species” to recruit wild pollinators and enhance pollination services, and therefore yield, in an organic day-neutral strawberry production system over two growing seasons. Flowering borage (Borago officinalis) strips were established on one end of three experimental fields of day-neutral strawberries. Strawberry yield and pollinator presence were hypothesized to decrease with distance from the flower strip. Though distance from the flower strip did not have a statistically significant impact on production parameters and pollinator presence, average strawberry yield and berry number was lowest in plots furthest from the flower strip in both years. Individual berry weights of the ‘Evie-2’ cultivar decline with distance from the flower strip, perhaps due to high pollination requirements. Strawberry floral visitor abundance declines steadily with distance from the flower strip in 2017, but this pattern is not clearly observed in 2018. The borage flower strip was highly attractive to insects, though primarily honey bees (Apis mellifera) and bumble bees (Bombus spp.). Primary strawberry flower visitors were hoverflies (Syrphidae), root maggot flies (Anthomyiidae) and native bees (Halictidae, Megachilidae, etc.), suggesting day-neutral strawberry pollination may rely more on Diptera taxa and small bees rather than larger pollinators like honey bees or bumble bees. More research is necessary to examine the potential of borage as a “magnet species” to facilitate day-neutral strawberry crop pollination. This project presents further evidence on the potential of pollinator farmscaping practices, such as annual flower strips, to recruit wild insect pollinators and improve pollination services for the benefit of small fruit crops.
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    Weighing the Risks and Benefits of Flowering Early for the Woody Perennial Prunus pumila (Rosaceae)
    (2022-05) Lake Diver, Danielle
    As global weather patterns become increasingly unpredictable, the need to study the impact of this phenomenon on natural and anthropocentric ecosystems alike is increasingly urgent. Based on climate change predictions for the rest of this century, much previous research has been conducted to reveal plants’ response to stress from heat and drought. However, fewer studies have focused on the response of perennial plants to false spring, or freezing after de-acclimation, another possible result of climate change. Plant phenology has already begun to advance by weeks since the middle of the twentieth century, which makes plants that flower and leaf out early particularly vulnerable to freezing damage from late spring frosts. Temperature during anthesis (when open flowers are present on a plant) has a significant impact on fertility, floral metabolism, and the production and quality of floral rewards that attract pollinators. Therefore, there may be advantages to flowering early that outstrip the potential risks, especially if pollinators also adjust their phenology to warming conditions. To determine whether earlier flowering plants were at risk for freezing damage, we first monitored a population of Prunus pumila with artificially delayed phenology over the course of the 2020 growing season. We measured flower and fruit number and mass, pollinator visitations, the effects of floral age on hand pollination, and seed germination. Consistent with previous studies, our results suggest that flowering time and temperature at anthesis affect reproductive success, with fewer fruits produced in warmer conditions. To build on this work, in 2021, we examined the effects of floral freezing on P. pumila pollinator attraction and reproductive success. Field-grown potted plants were exposed to one of two sub zero (°C) temperatures or a near-freezing control temperature. Flower samples were assessed for tissue damage through electrolyte leakage and stereo microscopy. In addition, a subset of flowers was hand pollinated or bagged to exclude insects and to gauge the effects of pollen limitation and selfing, respectively. Plants were then returned to the field and observed over the course of flowering for pollinator visitation and monitored for signs of successful fertilization and reproduction. This study showed that, in general, P. pumila buds and flowers are resistant to light freezing but not to hard freezing, but this difference did not affect overall pollinator visitation rate. Our findings will contribute to the current knowledge of Prunus, a global genus with high economic and ecologic value that could be greatly impacted by climate change.