John F. Barthell

Different solutions by bees to a foraging problem.

Honeybees (Apis mellifera) were used as a model insect system to explore how foragers solve problems involving cost as well as reward. Reward difference was created by varying sucrose molarity, whereas cost difference was created by varying flower-handling time in artificial flower patches. Unlike earlier work, flower-handling time was a function of stamen length rather than corolla length, such that longer stamens increased flower-handling time. When changing from short- to long-stamen flowers, access to nectar becomes limited to specific routes, which differ in difficulty. Experiments were performed with 2xa0μl and 6xa0μl sucrose rewards. Differences in reward and/or handling time were associated with flower colour difference (blue versus white flowers). Higher energy reward (2xa0M) and shorter handling time were preferred by bees when foraging problems involved only a reward or a handling-time difference, which followed energy maximization expectations. However, when the two variables were combined so that greater handling time was combined with higher reward, behaviour differed between individuals. Some bees made choices based solely on reward, some only on effort (handling time), and some simply on flower colour. These results contrast with early work where handling time was a function of corolla length and all bees avoided longer corollas. Results suggest that honeybees do not always behave as predicted by simple energy maximization principles; rather, individuality in choice arises when the foraging problem becomes more difficult because of increased complexity (dimensionality) of the problem.

Foraging Response of Turkish Honey Bee Subspecies to Flower Color Choices and Reward Consistency

Foraging behavior of Apis mellifera caucasica, A.m. carnica and A.m. syriaca in Turkey was studied for intrinsic subspecies-based differences. Models of forager flower-color fidelity, risk sensitive behavior and maximizing net gain were tested. Foragers were presented artificial flower patches containing blue, white and yellow flowers. Some bees of each subspecies showed high fidelity to yellow flowers, while others favored blue and white flowers. The degree of fidelity, however, differed among subspecies and was dependent upon which color was favored. Bees of all subspecies demonstrated risk indifferent behavior regardless of whether they favored yellow flowers or blue and white flowers. Flower handling time differed among subspecies and increased with reward quantity, and when a reward was present. Flight time between consecutive flowers also differed among honey bee subspecies. Foragers of all subspecies had a higher net gain when visiting flowers with consistent rewards.

Nest Site Selection Influences Mortality and Stress Responses in Developmental Stages of Megachile apicalis Spinola (Hymenoptera: Megachilidae)

ABSTRACT We examined stress responses and survival in developmental stages of the invasive solitary bee Megachile apicalis Spinola during two nesting seasons in the Central Valley of California to consider whether abiotic stress tolerance of its offspring contributes to this species successful colonization of the western United States. In 2001 and 2003, artificial nesting cavities were affixed to vertical plywood boards oriented to maximize nest cavity temperature and humidity differences: one side faced south (exposed to direct sun) and the other one faced north (shaded). After several weeks of nesting activity, we measured heat shock protein 70 (HSP70) concentrations in adults and offspring on 1 d in both years and offspring survival and mortality sources in 2003. In 2001, M. apicalis showed higher HSP70 concentrations in exposed nests than in shaded nests during all developmental stages, adults and their offspring. In 2003, overall survivorship was not significantly different between treatments because exposed nests experienced high offspring mortality caused by heat stress, whereas shaded nests suffered similarly high offspring mortality because of parasitoids. In both years of our study, females preferred shaded nests over exposed nests. M. apicalis successfully reproduces in grasslands of the Central Valley of California where offspring survive hot, dry nest sites and parasitoids in sufficient numbers to inoculate new grassland habitats, unpopulated by tolerance-limited native solitary bees, with incipient populations of this bee, M. apicalis.

Feature-positive and feature-negative learning in honey bees

SUMMARY Honey bees (Apis mellifera anatolica) were subjected to sequential trials where they were given the choice between a feature-positive and a feature-negative feeding plate. The ‘feature’ being manipulated is the presence of a single blue circle among three circles marking the location of a small sucrose reward. That is, a ‘feature-negative’ target had three white circles, while a ‘feature-positive’ target had two white circles and one blue one. Two experiments were performed. In both experiments, each bee was tested under two different reward scenarios (treatments). In the first experiment, during the feature-positive treatment bees received 4 μl of 2 mol l−1 sucrose when choosing the feature-positive plate, but received 4 μl of saturated NaCl solution (saltwater) when choosing the feature-negative plate. During the feature-negative treatment, bees were rewarded when visiting the feature-negative plate, while visitation to the feature-positive plate only offered bees the saltwater. The second experiment was a repeat of the first except that pure water was offered instead of saltwater in the non-rewarding feeding plate. As an experimental control, a set of bees was offered sequential trials where both the feature-positive and feature-negative plates offered the sucrose reward. Bee feeding plate choice differed between the feature-positive and feature-negative treatments in both experiments. Bees favored the feeding plate type with the sucrose reward in each treatment, and never consumed the saltwater or pure water when encountered in either treatment. Further, behavior of bees during both the feature-positive and feature-negative treatments differed from that of control bees. However, neither feature-positive nor feature-negative learning reached high levels of success. Further, a feature-positive effect was seen when pure water was offered; bees learned to solve the feature-positive problem more rapidly. When we tested bees using simply the choice of blue versus white targets, where one color held the sucrose reward and the other the saltwater, a bees fidelity to the color offering the sucrose reward quickly reached very high levels.

Learning and Memory During Foraging of The Blue Orchard Bee, Osmia lignaria Say (Hymenoptera: Megachilidae)

Abstract Social bees have been widely used as model systems for studying learning and memory. Much less is known about these phenomena in solitary bees, in spite of the fact that most bee species of the world are solitary. We explore the ability of the solitary blue orchard bee, Osmia lignaria Say, to learn and remember information when foraging. First we tested innate flower color preference using blue and white flower patches, and yellow and blue flower patches. The blue orchard bees showed a marked color preference for blue flowers in blue-white as well as in blue-yellow flower patches, even though all flowers provided the same reward. However, when white flowers offered the greater reward (either quality/molarity or quantity/volume) in blue-white dimorphic floral patches, the preference for blue readily decreased, which was not observed in control bees. Learning occurred more rapidly when a difference in reward volume rather than reward molarity was used. These results were approximately the same for males as for female bees. The information learned about flowers was retained for at least three hours.

A Decade of Progress: Lessons Learned in Developing the UCO Downtown.

For over a decade, the University of Central Oklahoma (UCO) has been engaged in defining its role within the Oklahoma City (OKC) Metropolitan Area. By 2013, an enhanced physical presence developed for UCO within OKC itself, including the creation of the Academy of Contemporary Music and the CHK|Central Boathouse. Afterwards, and in accordance with UCO’s strategic plan, Vision 2020, the Brookings Institution and the Greater Oklahoma City Chamber of Commerce explored links between OKC and workforce development needs, in parallel with planning for an Innovation District. Emerging from that planning is UCO Downtown, a flexible urban learning facility on the border of OKC’s Business District and the recently designated Innovation District. An upcoming renovation of offices and business incubators will provide additional space for the growth of UCO Downtown, as well as serving as home to Customized Education, a non-degree credit program serving metropolitan businesses. With substantial enrollment increases during the first three cycles of enrollment, programs have begun to anchor themselves into the OKC Downtown. The convergence of UCO Downtown with recent recommendations by the Brookings Institution forms the basis for UCO’s goal of serving OKC’s workforce (especially in STEM) as well as the broader OKC community (Arts, Business, Education, Government, etc.). The purpose of this paper is to describe a case study for the introduction of a learning facility in an urban environment (Oklahoma City) and to reflect on important lessons drawn from that experience. We hope this article will benefit others with similar objectives in their own institutional strategic plans.

Bee visitors of Centaurea solstitialis L. (Asteraceae) in an urban environment in northwestern Turkey

Information on the pollination ecology and floral visitors of the noxious weed Centaurea solstitialis is available for several populations in its invasive range, but limited information is available in its native range, with most studies conducted on the Greek island of Lesvos. Herein, we document the visitation pattern of bees and explore the relationship of bee body size and nectar availability in weedy populations of C. solstitialis from an urban environment within its native range in northwestern Turkey. Studies were conducted at patches of C. solstitialis in abandoned lots at the Uludağ University near the city of Bursa. A total of 41 species, including honey bees, belonging to five families and 19 genera were recorded. Small megachilid and halictid bee species were the most common visitors. Average nectar standing crop volume per floret was low (0.003–0.117xa0μL) and did not significantly vary throughout the day. Average bee head width significantly correlated with average nectar standing crop volume but did not significantly change throughout the day. Analyses of pollen loads as well as direct observations of bee foraging behavior indicate that a large number of bees visit C. solstitialis, primarily in search of nectar while carrying a large percentage of pollen grains of this plant species on their bodies. These results are similar to previous observations on a non-weedy population of C. solstitialis from the island of Lesvos.