Matching Items (6)

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Variance in bee species richness: seasonal, spatial, and temporal differences

Description

Bee communities form the keystone of many ecosystems through their pollination services. They are dynamic and often subject to significant changes due to several different factors such as climate, urban

Bee communities form the keystone of many ecosystems through their pollination services. They are dynamic and often subject to significant changes due to several different factors such as climate, urban development, and other anthropogenic disturbances. As a result, the world has been experiencing a decline in bee diversity and abundance, which can have detrimental effects in the ecosystems they inhabit. One of the largest factors that impacts bees in today's world is the rapid urbanization of our planet, and it impacts the bee community in mixed ways. Not very much is understood about the bee communities that exist in urban habitats, but as urbanization is inevitably going to continue, knowledge on bee communities will need to strengthen. This study aims to determine the levels of variance in bee communities, considering multiple variables that bee communities can differ in. The following three questions are posed: do bee communities that are spatially separated differ significantly? Do bee communities that are separated by seasons differ significantly? Do bee communities that are separated temporally (by year, interannually) differ significantly? The procedure to conduct this experiment consists of netting and trapping bees at two sites at various times using the same methods. The data is then statistically analyzed for differences in abundance, richness, diversity, and species composition. After performing the various statistical analyses, it has been discovered that bee communities that are spatially separated, seasonally separated, or interannually separated do not differ significantly when it comes to abundance and richness. Spatially separated bee communities and interannually separated bee communities show a moderate level of dissimilarity in their species composition, while seasonally separated bee communities show a greater level of dissimilarity in species composition. Finally, seasonally separated bee communities demonstrate the greatest disparity of bee diversity, while interannually separated bee communities show the least disparity of bee diversity. This study was conducted over the time span of two years, and while the levels of variance of an urban area between these variables were determined, further variance studies of greater length or larger areas should be conducted to increase the currently limited knowledge of bee communities in urban areas. Additional studies on precipitation amounts and their effects on bee communities should be conducted, and studies from other regions should be taken into consideration while attempting to understand what is likely the most environmentally significant group of insects.

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Date Created
  • 2017-05

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Handling the Heat: Plasticity of an Arthropod Pest in Response to the Urban Heat Island

Description

In recent years, ecologists have begun to study the effects of urbanization on species diversity. While urban areas generally suffer decreased biodiversity, some species, termed “urban exploiters”, not only live

In recent years, ecologists have begun to study the effects of urbanization on species diversity. While urban areas generally suffer decreased biodiversity, some species, termed “urban exploiters”, not only live in the city but depend on urban resources to thrive. It is hypothesized that urban exploiters may succeed in part due to phenotypic plasticity, in which organisms rapidly adjust their physiology or behavior to adapt to novel environmental contexts. In the city, it may be adaptive to display thermal plasticity, as the urban heat island effect caused by concrete and asphalt infrastructure prevents cooling at night. In this study, we observed the decorated cricket Gryllodes sigillatus, an invasive urban exploiter found in metropolitan Phoenix, in two separate experiments. We hypothesized that heat tolerance and activity are both plastic traits in this species. In Experiment 1, we predicted that knock-down time, a measure of heat tolerance, would be negatively affected by acclimation to a laboratory environment. Our results suggest that heat tolerance is affected by recent thermal regimes and that laboratory acclimation decreases knock-down time. In Experiment 2, we predicted that activity would increase with temperature until a point of extreme heat, at which point activity would decline. Statistical analysis for the second experiment reveals that activity decreases at 33°C, a natural urban extreme. This suggests either that 33°C is a thermal limit to physiology or that G. sigillatus is able to alter its behavior to exploit local thermal heterogeneity.

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Created

Date Created
  • 2015-05

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Wild bee foraging abundance on native sunflower Helianthus annuus L. versus Helianthus cultivar sunflowers in an urban habitat

Description

Through the months September-November of 2017 a study was conducted to determine if bees prefer the sunflower, Helianthus annuus, native to Arizona, or a cultivar Helianthus sunflower in an urban

Through the months September-November of 2017 a study was conducted to determine if bees prefer the sunflower, Helianthus annuus, native to Arizona, or a cultivar Helianthus sunflower in an urban environment. The study was executed in a small, controlled urban environment on Arizona State University West campus. Seven identified bee species and forty-nine specimens were collected, of the forty-nine specimens, two bees were reported on the Helianthus cultivar supporting native floral host preferences of native species. Variables such as nectar, pollen, floral color, and floral height were not measured, however, when the floral host genus was maintained wild bees visited the native Helianthus host significantly more yielding a supportive two-tailed p-value of 2.97x10-5. Three trends were identified in correlation with the experiment: 1) Bees foraged on native Helianthus annuus over the Helianthus cultivar, 2) Generalist species were more abundant than specialists on the Helianthus annuus, 3) Honey bees (Apis mellifera) were the most abundant species present. While not considered a trend, low floral diversity and abundance may explain the low diversity of bee species observed on the Helianthus. Floral host and pollinator desynchronization may also have affected bee diversity and abundance. Analysis of bee abundance and diversity support that wild bees may prefer native floral hosts over cultivar floral hosts when the floral genus, temperature, and time was controlled for in an urban environment.

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Created

Date Created
  • 2018-12

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Foraging Behavior in Native and Non-Native Bee Species at the Desert Botanical Garden

Description

One can argue that bees are the most unique insects in the animal kingdom due to their invaluable services they provide on a global level. Their importance goes beyond their

One can argue that bees are the most unique insects in the animal kingdom due to their invaluable services they provide on a global level. Their importance goes beyond their capability of pollination; it is shown in their environmental impact and maintenance of the world's food supply. It is evident that the bee population is experiencing a serious and rapid decline that has resulted in changes to ecosystems in the past couple of decades. In order to resolve these issues, further research must be conducted to understand what humans can do to benefit their species' longevity. It is necessary for knowledge regarding bees, specifically their foraging behavior, to improve so humans can understand their essentiality to not only them, but the world. The focus of this study is to address any differences in foraging behavior between Apis mellifera, the honey bee, and native bee species. Other questions were answered including: do native and non-native bees have floral host preferences? Do native and non-native bees visit a variety of floral hosts? Experimental procedures were conducted to address these questions, which involved netting bees at differing times in four varying garden locations at the Desert Botanical Garden in Phoenix, Arizona. Then, the preparation of bee pollen and plant pollen slides along with bee mounting was performed. After the completion of data analysis, it was discovered that the preliminary data showed different foraging behavior between native and non-native bee species. Further studies are pertinent in obtaining statistically significant data due to an insufficient sample proportion. This is crucial in understanding the true differences in behaviors between both bee species.

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Created

Date Created
  • 2018-12

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Floral UV Pattern and Abundance Effects on Pollinator Foraging Behavior

Description

Honey bees are vital to human society due to their pollination services but are currently under threat due to various factors. In order to avoid drastic declines in bee populations,

Honey bees are vital to human society due to their pollination services but are currently under threat due to various factors. In order to avoid drastic declines in bee populations, it is important to fully understand factors that contribute to pollinator health and efficiency. The focus of this experiment were UV markings, commonly referred to as nectar guides. While various studies have found nectar guides to influence pollinator activity, relatively few experiments have been conducted to see how UV patterns and/or UV coverage of nectar guides affects bee foraging, which is what our experiment attempted to explore. Our hypothesis was that UV coverage has a positive impact on bee foraging activity, but that full UV coverage would lower foraging activity, we also hypothesized that UV pattern would also influence foraging activity and that pollinators will prefer circular patterns. In our experiment we created artificial nectar dispensing flowers with differing UV markings and placed them out in a natural environment and recorded pollinator visitation. We then utilized a two-way ANOVA to determine if there was a statistical correlation between UV abundance and/or UV pattern on pollinator activity. Our results revealed no statistical correlation for either UV coverage (p = .389) nor UV pattern (p = .437) to pollinator activity. While no statistical correlation was found, graphical analysis of the mean between different UV groups revealed a noticeable flower preference was seen for flowers with at least some level of UV compared to no UV and a slight increase in activity for circular patterns compared to radial patterns. This suggests that perhaps UV abundance and pattern plays a minor role in pollinator activity but nothing that is statistically significant. We suggest further follow up research to improve and refine our methods and utilize a greater range of patterns and abundance size with a larger sample size to better understand the role UV pattern and UV coverage has on pollinator foraging activity.

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Created

Date Created
  • 2019-05

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The Effects of Extreme Urban Heat on Behavioral Syndromes of Juvenile Black Widow Spiders, Latrodectus hesperus

Description

Urbanization rapidly alters the environment, leading to a decrease in biodiversity in urban areas. A challenge associated with urbanized areas is the increased heat caused by the urban heat island

Urbanization rapidly alters the environment, leading to a decrease in biodiversity in urban areas. A challenge associated with urbanized areas is the increased heat caused by the urban heat island effect. Heat may have an important impact on arthropods particularly due to their status as ectotherms. Animal behavior reveals how individuals interact with their environment. A behavioral syndrome describes consistent individual differences in behaviors that are correlated across different behavioral contexts or situations. Understanding the Western Black Widow's behavioral responses to the urban heat island effect has important implications for the control of a pest species. In this study, the relationship between rising urban temperatures and voracity, web-building, and cannibalism behaviors of juvenile Western Black Widows was examined. Spiders raised in the urban temperature treatment were predicted to have more aggressive behavioral syndromes, characterized by shorter latencies to forage, greater web-building activity, and shorter latencies to cannibalize as compared to spiders raised in rural or intermediate temperature treatments. A correlation between the latency to attack the first fly and second fly was found, however there were no other correlations evidencing a behavioral syndrome. Temperature was found to affect foraging, web-building, and cannibalism behaviors where spiders in urban areas demonstrated increased activity in all behavioral contexts. The possession of behavioral plasticity rather than a behavioral syndrome is likely what allows Black Widows to be successful urban pests.

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Created

Date Created
  • 2018-05