Urbanization is among the greatest threats to biodiversity on the planet, and is projected to increase in magnitude in coming years. This growing threat makes it important to better understand how urbanization may impact vital ecosystem services, such as pollination. Studies on the impact of urbanization on pollination vary wildly in their findings. This study analyzed multiple aspects of pollination success in common milkweed populations varying in urbanization level, including insect community composition, pollen removal/deposition, and fruit/seed production. By analyzing multiple pollination aspects we can determine the overall mechanism in which urbanization instills on the entire pollination process. Overall, urbanization increased insect visitation rate, and altered insect composition, with small bees and bugs/beetles having a larger presence in urbanized areas. Pollen removal also increased with urbanization, while other factors of pollination success were unaltered. These results suggest that increased urbanization can differentially impact components of the pollination process.

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Chasing Butterflies is a city planning/landscape proposal for Bromma Airport that strives to: • Imagine a future eco-city through a biophilic lens. • Apply biophilic ideas relating to plants.   • Move towards meeting the criteria set-up by Stockholm´s municipality. • React to the proposal “Bromma Parkstad” by the Swedish Environmentalist party. The method consisted of:  • Support design decisions by referring to scientific data and theories from the course Trädgårdens Biologi, orienteringskurs (Introduction to Garden Biology) at Stockholm University and other scientific articles relating to the subject such as phytoremediation (decontamination through vegetation), pollination and the history of Bromma Airport. • Literature research on the following topics: the history of the Swedish allotment movement, the biophilic ideology, greenhouse living, environmental psychology, landscape theories regarding non-human migration patterns and ecological theories concerning pollination.  • Searching through digital archives of governmental/municipality reports.  Thesis question: How can architecture help generate biodiversity and how can non-human actors be integrated into a new eco-city at Bromma Airport?    Different types of cultivated land (allotments, private gardens, community gardens, parks, urban farming, and greenhouses) have been studied to investigate how architecture can help generate biodiversity on multiple scales.  Furthermore, there are several so called "forever chemicals" present at the site. For Bromma Airport to become inhabitable, the soil would have to go through a thorough cleans, where the use of plants is the most efficient alternative.  The strategy is to: • Keep all material on-site, since relocating to a different site would only move the problem.  • Use plants for cleansing and letting the land heal in its own time. • Maximize different types of cultivated land in an urban environment.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第25353号 / 農博第2619号 / 新制||農||1108(附属図書館) / 学位論文||R6||N5525 / DGAM / 京都大学大学院農学研究科地域環境科学専攻 / (主査)准教授 大澤 直哉, 教授 日本 典秀, 教授 田中 千尋 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

<p dir="ltr">Lack of adequate pollination limits yield in many specialty crops, and this pollen limitation is determined by crop pollination requirements and pollinator community dynamics. Bee communities and degree of pollen limitation is variable between crops and regions, necessitating a crop-specific, regional approach to describing pollination services. Despite primarily producing agronomic crops, Indiana produces a wide variety of specialty crops, including apples, blueberries, watermelons, and tomatoes (grown for processing in open fields and fresh market in high tunnels). Each crop has variable bloom phenology, pollination requirements, and associated management practices (e.g., thinning in apples and protective cover in high tunnels), with potential implications for their pollinator communities and pollination services. This thesis aims to 1) use flower observations and pan traps to compare pollinator communities between crops, including the contributions of managed and wild bees, community diversity, and composition and 2) assess pollen limitation in each crop using pollination experiments. The study took place on commercial farms throughout Indiana over the course of three summers (2022-2024). We found that distinct pollinator communities persisted in each crop system, with spring-blooming apples and blueberries dominated by honey bees (<i>Apis mellifera</i>) and summer-blooming tomatoes and watermelons dominated by wild bees, particularly <i>Bombus</i> spp. in tomatoes and <i>Lasioglossum</i> spp. in watermelon. We also found evidence of pollen limitation with respect to fruit set in all crop systems except for apples (measured at harvest, after apple thinning occurred). Evidence of pollen limitation with respect to fruit weight was detected only in field tomatoes and apples, but not other crops. Meanwhile, insect pollination increased fruit set and weight in almost every crop, except for high tunnel tomatoes, implying reduced pollination services in this semi-protected system. Our results highlight the importance of protecting wild pollinator communities in Indiana, particularly in watermelons and tomatoes, and identify yield gaps in multiple crops, especially tomatoes, which could be addressed by increasing pollination services. This crop-specific information is a valuable first step in encouraging growers to adopt pollinator friendly management decisions and protecting pollination services in Indiana.</p>

Buzz-pollination or pollination by vibration occurs in several families of angiosperms including some important commercial crops such as potatoes and tomatoes. Buzz-pollinated flowers release pollen via small pores or slits on the anther’s tip that require the use of vibrations by specialized pollinators, usually bees, to remove the pollen. Some buzz-pollinated species have elaborate floral morphologies including dimorphic anthers within the same flower (heteranthery), and mirror-image flowers (enantiostyly) where the style is reciprocally deflected to either the left or right side of the floral axis. The complex floral morphology and buzz-pollination syndrome seen in these species require a close physical interaction between the sexual organs of the flowers and the bodies of insect visitors. Despite the broad taxonomic distribution of buzz-pollination in angiosperms (more than 60 families are buzz-pollinated) relatively few studies have described the pollination ecology of these species under natural conditions. The main goal of the present work was to characterize the pollination biology, mating patterns and antagonistic interactions (e.g. pollen theft) in natural populations of a buzz-pollinated species. For this purpose, I studied Solanum rostratum (Solanaceae), a buzz-pollinated, self-compatible, annual weed with complex floral morphology (both enantiostylous and heterantherous flowers). This species usually grows in disturbed areas in its native range (Mexico) and has become invasive around the world. My research was divided into three components. First, I characterized the pollination and reproductive biology of natural populations in Mexico. I performed floral manipulations in six natural populations of S. rostratum to estimate fruit and seed set. In three of these populations, I carried out 115 hours of pollinator observations and quantified the incidence of pollinators versus pollen thieves. I also measured the efficiency of a subset of floral visitors in triggering fruit set after single visits. Second, I investigated whether morphological correspondence between the size of the pollinator’s body and floral morphology influences pollen transfer. In experimental arrays, I exposed flowers of S. rostratum that varied in the distance between their sexual organs, to bumblebees (Bombus terrestris) of different sizes, and recorded pollen deposition and fruit and seed production. Finally, I determined the mating system (i.e. the proportion of self- and cross-fertilized offspring) of natural populations in Mexico and of introduced populations in the United States of America, using newly developed microsatellite markers. My results show that S. rostratum is visited by a wide range of bees of different sizes (0.9–9.8 mm in thorax diameter), but that only a small subset of these visitors act as pollinators. Most visitors act as pollen thieves, consuming pollen while effecting little or no pollination. I also found that correspondence between a pollinator’s size and the separation of the S. rostratum sexual organs determines pollen deposition and fruit production; pollen deposition decreased when bees were small relative to the distance between the sexual organs visited the flowers. My genetic analyses show that natural populations of S. rostratum maintain a relatively high outcrossing rate (tm = 0.75 ± 0.03) across the native and introduced range. Furthermore, genetic diversity is reduced in invasive populations, but this is not accompanied by changes in mating system. My work shows that the morphological fit between the pollinator and the flowers is important in determining the dynamics of pollen transfer and fruit production in this buzz-pollinated plant. Distinguishing between pollinators and pollen thieves in buzz-pollinated plants is essential for understanding the evolution of buzz-pollination, as pollen theft could be a major selective force for these species.