Bumblebees (genus Bombus) are key pollinators in many ecosystems, yet their foraging performance and pollination efficiency are highly sensitive to environmental conditions, particularly temperature. As global temperatures undergo rapid changes due to climate change, understanding how thermal variation affects bumblebee behavior, physiology, and biomechanics is crucial for predicting potential disruptions to pollination services. Bumblebees possess a unique ability among insects to generate internal heat and are regarded as cold-adapted specialists. However, this adaptation also makes them highly vulnerable to rising environmental temperatures. Using a combination of laboratory experiments and field observations with commercial bumblebees, this thesis explores the impact of environmental temperature on bumblebee foraging behavior, flight control, vision, and pollination performance. In Chapter I, we examine how temperature impacts commercial bumblebee colonies by surveying foraging activity in a field site using both radio frequency identification (RFID) tags and manual surveys. We measured colony activity (number of departures and arrivals) as well as bumblebee body temperature upon depature and arrival and monitored colony and environmental temperature. Our results showed that while Biobest workers began foraging at cooler temperatures and increased both their foraging duration and pollen collection as environmental temperature rose, Koppert colonies exhibited relatively stable foraging behavior across temperatures, with shorter trips and less temperature-dependent pollen collection. These findings highlight the need to consider breeder-specific traits when choosing colonies for crop pollination in different climates. In Chapter II, we used laboratory experiments to understand how environmental temperature affects bumblebee body temperature and thermoregulation during different behaviors (i.e., during resting, pre-flight, and post-flight). We measured head, thorax, and abdomen temperature. We found that the effect of environmental temperature on bumblebee body temperature differs across behavioral contexts and that bumblebees use a counter-current heat exchanger to thermoregulate during during/ after flight. In Chapter III, we aimed to understand how increasing temperatures and decreasing light availability affect bumblebee visual performance and flight control. We measured visual performance by recording electroretinogram responses of bumblebees at different temperatures and light intensities. Additionally, by recording bumblebees flying during periods of dim and bright light at different temperatures, we assessed components of flight control, including flight speed, straightness, and centering. Photoreceptor SNR peaked at intermediate temperatures, declining at both low and high extremes. We found that bumblebees increase their flight speed as temperature increases, but only in bright light and this is aided by the increase in visual performance. On the contrary, during periods of dim light and lower temperatures, bumblebees fly slower likely caused by decrase in the visual performance. In Chapter IV, we examined how temperature influences the foraging behavior (i.e., number of flowers visited and time spent on each flower) of bumblebees using buzz-pollinated Solanum rostratum plants. We also investigated the vibratory mechanics of buzz pollination—a process in which bees generate rapid thoracic vibrations to extract pollen from flowers with poricidal anthers. We found that bumblebee foraging activity is affected by temperature, with bumblebees decreasing the amount of time spent on each flower and  visiting more flowers per minute. This temperature-induced variation in behavior affected the reproductive outcome of the plants, with fewer fruits and seeds being produced by plants that were pollinated by bees at the higher temperature.  We also found that vibration frequency, amplitude, and pollen release efficiency are significantly affected by temperature. By integrating ecology, behavior, physiology, and biomechanics, this thesis provides novel insights into the thermal sensitivity of bumblebees and their pollination effectiveness. The results emphasize the vulnerability of bumblebee populations and pollination services in a changing climate, underscoring the need for conservation strategies that promote pollinator resilience.